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Menstrual Cycle · Period Care
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In one pass The menstrual cycle is not the uterus acting alone.
Educational content, not medical advice — consult a clinician.
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Chapter 1
How the cycle works
The menstrual cycle is not the uterus acting alone. It is a four-stage relay: the hypothalamus signals the pituitary, the pituitary directs the ovaries, and the estrogen and progesterone the ovaries release decide how the lining of the uterus (the endometrium) grows and when it sheds. Mood, body temperature, sleep and appetite are pulled along by the same line, and the pain, mood and bleeding changes covered later all start here.
Ovulation splits the cycle in two: before it is the follicular phase, after it the luteal phase. The most useful point is that the luteal phase is fairly fixed, often around 14 days, and differences in cycle length come mainly from the follicular phase. So someone whose period comes every 35 days usually just has a long follicular phase, and a 21-day cycle is not necessarily a problem either. The range commonly used as normal is 21–35 days. To estimate ovulation, count back 14 days from the day your next period is expected; that is more accurate than always assuming day 14.
Some situations should not wait: bleeding so heavy that you feel dizzy or your heart races; a positive pregnancy test with sudden severe abdominal pain (an ectopic pregnancy has to be ruled out); or thoughts of harming yourself before your period. If any of these happens, seek care immediately.
Ovulation splits the cycle in two: before it is the follicular phase, after it the luteal phase. The most useful point is that the luteal phase is fairly fixed, often around 14 days, and differences in cycle length come mainly from the follicular phase. So someone whose period comes every 35 days usually just has a long follicular phase, and a 21-day cycle is not necessarily a problem either. The range commonly used as normal is 21–35 days. To estimate ovulation, count back 14 days from the day your next period is expected; that is more accurate than always assuming day 14.
Some situations should not wait: bleeding so heavy that you feel dizzy or your heart races; a positive pregnancy test with sudden severe abdominal pain (an ectopic pregnancy has to be ruled out); or thoughts of harming yourself before your period. If any of these happens, seek care immediately.
Mechanism · Why periods happen and what they touch
Why periods exist at allMost mammals do not menstruate: when there is no pregnancy, their uterine lining is slowly reabsorbed rather than shed. Humans, some other primates, some bats and elephant shrews are different. They show spontaneous decidualization: even without an embryo, the lining turns into decidua during the luteal phase, the kind of tissue that is ready for a pregnancy.
So when the corpus luteum (the structure left behind after ovulation) breaks down and progesterone falls, a lining that has already decidualized cannot simply revert. Its blood supply fails, and it sheds and bleeds: that is a period. Why prepare in advance like this? One evolutionary hypothesis (Emera 2012) holds that the human embryo burrows deep into the uterine wall when it implants, so the mother's lining has to get its defenses ready beforehand, and menstruation is a by-product of that advance preparation. It is a hypothesis, not a settled conclusion.
Menstruation is not flushing out waste blood or toxins
Menstrual fluid is roughly estimated to be endometrial tissue (about 35–50%) plus blood (about 30–50%), with cervical mucus and products of the vaginal bacteria.It contains no toxins and does not need to be flushed out completely. This is one of the most common misunderstandings on the Chinese-language internet.Treating the color of menstrual blood as a health indicator is also over-mystified. The color depends mainly on how long the blood has stayed in the body and oxidized: bright red is fresh, dark red or brown has oxidized, and none of it maps onto ideas such as cold-dampness or toxins.
How the cycle reaches the rest of the body
Basal body temperature (taken on waking, before getting up): it rises by 0.3–0.5 °C in the luteal phase. It can confirm after the fact that ovulation happened, but it cannot predict ovulation in advance.Temperature regulation: in the luteal phase, the range of temperatures the body finds comfortable narrows, so the same room feels warmer. A small group of neurons in the hypothalamus that help regulate both reproductive hormones and body temperature (KNDy neurons) is involved in menopausal hot flashes, and part of the same pathway may be at work here (see the Perimenopause story).Sleep structure: late in the luteal phase, rapid eye movement () sleep decreases and night-time waking increases. Allopregnanolone, a breakdown product of progesterone, strengthens the action of (the brain's main brake signal), so early in the luteal phase it may help you fall asleep; late in the luteal phase it drops quickly and sleep tends to become lighter. That second step is still reasoning rather than measurement.Appetite: energy intake rises in the luteal phase. A review (Buffenstein 1995) that pooled 19 studies found an average of about 1.0 MJ (about 240 kcal) more per day, with individual studies above 2.5 MJ a day, and a pull toward carbohydrates and fat.Skin oil and acne: progesterone rises after ovulation and the oil glands become more active, and in many people acne peaks 3–5 days before a period.Breasts: breast tissue grows late in the luteal phase and becomes tender, a normal effect of progesterone.
A period is not an inconvenience to put up with, nor mystical feminine energy. It is an endocrine process that can be understood, measured and acted on.
Numbers · Is a cycle that isn't 28 days abnormal?
A cycle has to be 28 days to be normal is a common misconception.The ranges commonly used as normal (the FIGO 2018 classification judges frequency, regularity, period length and blood loss as separate features; the figures below are the ones commonly used in clinical practice):
Cycle length: 21–35 days (up to 45 days in the first 5 years after the first period, and as short as 17 days around menopause)Period length: 2–7 daysBlood loss: 5–80 mL (from Hallberg's classic 1966 population study; in research, more than 80 mL counts as heavy menstrual bleeding, HMB)Variation between cycles: a difference of ≤ 7–9 days between two consecutive cycles is normal variation
Signs that really deserve attention (covered in detail in the chapter When bleeding is abnormal)
Cycles shorter than 21 days or longer than 35 days for ≥ 3 cycles in a rowPeriods lasting more than 7 days or less than 2 daysFlow that feels clearly heavier (soaking through 1 pad in an hour, or large clots); you can record it semi-quantitatively with the PBAC score, a chart that scores how soaked each pad or tampon isBleeding between periodsBleeding after sexNo period for 3 months or more (amenorrhea) when you are not pregnant or breastfeeding
Common physiological reasons for irregular cycles (not necessarily disease)
The first 2–5 years after the first period: the hypothalamic-pituitary-ovarian axis (HPO axis) is not yet mature, and cycles without ovulation are commonAround menopause (after 45): the rhythm of this axis starts to falter; see the Perimenopause storyStress: acute or chronic stress can suppress the HPO axis through the stress axis ( axis) and delay ovulationToo little energy: dieting, or training hard without eating enough, can lead to functional hypothalamic amenorrhea (FHA), in which the brain pauses the signal for ovulation because energy is short; this is what sports medicine calls low energy availabilitySharp weight change: losing 10% of body weight in a short time, or gaining weight suddenly, can disrupt the cycleCrossing time zones and shift work: see the Shift Work · Circadian Misalignment story
Why tracking the cycle is worth it
A record of 3–6 cycles is the cheapest diagnostic tool there is, and often tells more than a single blood test for any one hormone.Worth recording: the first day of each period, how long it lasts, flow (light, medium or heavy), pain (0–10), abnormal bleeding, and main symptoms (premenstrual syndrome, mood, headache).Optional: basal body temperature (taken on waking, before getting up) and changes in cervical mucus (the Billings method). These help identify the fertile window when trying to conceive; they are not a contraceptive method on their own.Apps: Clue, Flo or the built-in Apple Health feature all work. For privacy, prefer apps that store data mainly on your device, and be careful about data sent across borders (since Roe v. Wade was overturned in the US, some states have seen menstrual data obtained by courts).
Chapter 2
When bleeding is abnormal
Whether a period problem can wait a bit longer is one of the medical decisions people put off most often. Start by putting numbers on normal: a cycle of roughly three to five weeks, a few days of bleeding, and an upper limit on blood loss used in research, above which bleeding counts as heavy. It is hard to measure precisely day to day, so how fast pads soak through and whether there are large clots are the more useful rough signs. In clinical practice today, what matters more is whether the bleeding is affecting your health, work and daily life.
The causes behind abnormal uterine bleeding fall into two groups: structural problems that imaging can see (such as polyps or fibroids), and functional problems it cannot (such as clotting or ovulation problems). Two situations should not be put off: bleeding so heavy that you feel dizzy or your heart races means going to the emergency department, and any vaginal bleeding after menopause means seeking care promptly to rule out endometrial cancer.
The causes behind abnormal uterine bleeding fall into two groups: structural problems that imaging can see (such as polyps or fibroids), and functional problems it cannot (such as clotting or ovulation problems). Two situations should not be put off: bleeding so heavy that you feel dizzy or your heart races means going to the emergency department, and any vaginal bleeding after menopause means seeking care promptly to rule out endometrial cancer.
Numbers · How much bleeding is too much
The ranges commonly used as normalCycle length: 21–35 daysPeriod length: 2–7 daysBlood loss: 5–80 mL; in research, more than 80 mL counts as heavy menstrual bleeding
80 mL is roughly 16 fully soaked standard pads. Research has found, however, that many women who seek help for heavy periods do not actually lose more than this when it is measured, and blood loss cannot be weighed precisely in daily life anyway. So, as the Critchley 2020 review describes, heavy menstrual bleeding is now defined clinically as bleeding heavy enough to affect your physical, social, emotional or financial quality of life. A useful rough guide: soaking through one pad an hour for 2 hours or more, having to get up at night to change, or passing clots larger than 2.5 cm all suggest heavier than normal bleeding.
The three red flags to take most seriously
Bleeding heavy enough to bring dizziness, a racing heart or pallor: seek care promptly to check for anemiaAny vaginal bleeding after menopause: endometrial cancer has to be ruled out firstSevere period pain that painkillers cannot control and that disrupts work or study: get checked for endometriosis
As for what lies behind abnormal uterine bleeding (AUB), doctors work through the FIGO classification one cause at a time: one group is structural problems visible on imaging (polyps, adenomyosis, fibroids, malignancy), the other is functional problems imaging cannot show (clotting, ovulation, the lining itself, medications). The system is named PALM-COEIN after the initial letters of these causes.
Red flag · Which signs need care, and how soon
Red flags: if you see these, go to gynecology without delayAcute (this week):
Abnormally heavy bleeding with dizziness, a fast heart rate or pallor: go to the emergency department to rule out anemia the body can no longer compensate forAny vaginal bleeding during pregnancyHeavy bleeding after sexAn unexplained lump in the abdomen together with a disrupted cycle
Subacute (this month):
Cycles longer than 35 days or shorter than 21 days for ≥ 3 cyclesPeriods lasting more than 7 daysRepeated bleeding after sexBleeding between periods (apart from occasional spotting around ovulation)Any vaginal bleeding after menopause: ruling out endometrial cancer is the top prioritySevere period pain, not working, and an impact on work or school: screen for endometriosisNo period for more than 3 months (once pregnancy is ruled out)Heavy periods together with easy bruising, nosebleeds or bleeding gums: screen for a clotting disorder (watch for vWD)
What some of these terms mean: anemia the body can no longer compensate for means blood loss has outrun the body's ability to cope; NSAIDs are non-steroidal anti-inflammatory drugs such as ibuprofen; vWD is von Willebrand disease, a common inherited clotting disorder.
Do not underestimate how much periods affect life
Endometriosis often takes a long time to diagnose. The Critchley 2020 review estimates that the diagnostic delay can reach 7–10 years; Nnoaham 2011, a multicenter cross-sectional study in ten countries, measured an average of 6.7 years from first symptoms to surgical diagnosis, with most of the delay in primary care. Many women are told period pain is normal, just put up with it until an infertility work-up finally finds it.Heavy periods easily lead to iron-deficiency anemia, which shows up as long-term tiredness, poorer concentration and lower productivity. Women who feel tired all the time should first check for heavy periods and have their measured (see the Iron story).Schoep 2019, a nationwide cross-sectional survey in *BMJ Open* (N=32,748): period symptoms cost an average of 8.9 days of lost productivity a year. Most of it was not time off (a mean of 1.3 days) but working while unwell: 80.7% reported this, on a mean of 23.2 days a year, with output down by roughly a third on those days.Just put up with it is not a virtue; it is the cost of not having the information.
The basic work-up usually done at a visit for abnormal periods
Always: a pregnancy test (β-hCG) to rule out pregnancy and ectopic pregnancyA , ferritin, thyroid-stimulating hormone () and prolactin (PRL)A clotting panel, plus von Willebrand factor (vWF) antigen and activity (especially for teenagers who have had heavy periods since their first period)A pelvic ultrasound (transvaginal preferred) to look at fibroids, polyps, the thickness of the lining and the ovariesIf needed: hysteroscopy (to look for polyps and rule out endometrial cancer), an endometrial biopsy (heavy bleeding at 45 or older, or a lining thicker than 11 mm after menopause), and MRI (deep adenomyosis or complex endometriosis)
Medical decisions about abnormal periods do not call for heroics. Enduring is not a virtue; measuring and getting checked early are.
schoep-2019-bmjopen-productivity
Chapter 3
Where period pain comes from
Primary dysmenorrhea (period pain with no underlying disease) has no structural cause; its root is a burst of prostaglandins in the uterine lining in the first two days of a period. After the corpus luteum breaks down and progesterone falls, cells in the lining turn arachidonic acid from their membranes into large amounts of the prostaglandins PGF2α and PGE2, using the enzyme cyclooxygenase-2 (COX-2). PGF2α makes the smooth muscle of the uterus contract hard and cuts its blood flow, causing a pain like that of muscle starved of blood; PGE2 brings nausea, diarrhea and headache.
That is why the first-line drug is a non-steroidal anti-inflammatory drug (, such as ibuprofen) that blocks this step, rather than acetaminophen, and why it is best started before the period is due: taken only once the pain has begun, it often works less well. Primary dysmenorrhea usually starts in the teenage years. Pain that first appears after 25, gets worse month by month, or does not respond to painkillers looks more like secondary dysmenorrhea, caused by an underlying disease, and needs a gynecology check.
That is why the first-line drug is a non-steroidal anti-inflammatory drug (, such as ibuprofen) that blocks this step, rather than acetaminophen, and why it is best started before the period is due: taken only once the pain has begun, it often works less well. Primary dysmenorrhea usually starts in the teenage years. Pain that first appears after 25, gets worse month by month, or does not respond to painkillers looks more like secondary dysmenorrhea, caused by an underlying disease, and needs a gynecology check.
Mechanism · Why prostaglandins make the uterus hurt
Period pain comes in two kinds, and they are handled completely differently:Primary dysmenorrhea: there is no underlying disease; it is functional pain driven by prostaglandins. The Iacovides 2015 review estimates that it affects 45–95% of women who menstruate, most often teenagers and women in their early twenties.Secondary dysmenorrhea: there is an underlying disease, such as endometriosis, fibroids, adenomyosis or pelvic inflammatory disease. It usually starts after 25, as new pain or pain that keeps getting worse.
Primary dysmenorrhea is one of the cleanest examples of understand the mechanism and you can aim the drug precisely.
Where the prostaglandins come from
This is a real chemical chain (Iacovides 2015): the corpus luteum breaks down → progesterone falls → lysosomes in the lining's cells release their enzymes → phospholipase A2 cuts arachidonic acid (AA) from membrane phospholipids → cyclooxygenase-2 (COX-2) → large-scale synthesis of PGF2α and PGE2.
On days 1–2 of a period, the concentration of PGF2α in the uterine lining rises to 3–7 times its level in the follicular phase.PGF2α makes the uterine smooth muscle contract hard. Pressure inside the uterus can reach about 150–180 mmHg (normally < 80 mmHg), blood flow falls, and the result is pain from lack of blood. The principle is like angina: both are pain from muscle starved of blood, here in the uterus. PGF2α also makes pain-sensing nerve endings more sensitive, lowering the threshold for pain.PGE2 brings whole-body symptoms: nausea, vomiting, diarrhea and headache.
Clinical · How to take NSAIDs so they work
Why come firstNSAIDs (non-steroidal anti-inflammatory drugs) include non-selective COX inhibitors (ibuprofen, naproxen, diclofenac) and selective COX-2 inhibitors (celecoxib).They block the step from arachidonic acid to prostaglandins directly, which means tackling the pain at its source.A Cochrane review (Marjoribanks 2015, 80 randomized trials) found that NSAIDs relieve pain clearly better than placebo. Put in terms of people: about 18% of women on placebo got moderate or better relief, compared with 45–53% on NSAIDs. The price is somewhat more side effects: if 10% of the placebo group had side effects, 11–14% of the NSAID group did. The authors rated the evidence for most comparisons as low quality, mainly because the trials reported their methods poorly.Compared with acetaminophen (paracetamol, Tylenol), NSAIDs appear more effective, but that rests on only 3 trials and low-quality evidence (Marjoribanks 2015).Another figure often quoted: for ibuprofen 400 mg versus placebo, the (NNT, how many people must be treated for one more to benefit clearly) is about 2.4.
Timing (news to many people)
Waiting until it hurts often makes the drug work less well: by then the prostaglandins have already been released in large amounts and pain signaling has already been amplified.The usual approach is to start taking it regularly 1–2 days before the period is due, keeping blood levels steady so prostaglandins do not build up.Ibuprofen: 400 mg every 6 hours, on days 1–3 of the period when pain is worst. Do not exceed 2400 mg in a day; that is the daily ceiling commonly used when a doctor prescribes it, and the daily limit printed on over-the-counter packs is often lower, so follow the label.Naproxen: a first dose of 500 mg, then 250–500 mg every 8–12 hours.Mefenamic acid: both inhibits COX and blocks prostaglandin receptors; some studies found it better than ibuprofen, but it has slightly more stomach and bowel side effects.After 2–3 days the prostaglandin peak has passed, and you can take it only as needed.
Safety · NSAID side effects and who should avoid them
How long to take them: period pain usually needs only 3–5 days in a row. Starting 1–2 days before the period and continuing to day 2–3, 3–4 days in total, is enough to cover the prostaglandin peak. If you need more than 5 days each cycle to control the pain, see a gynecologist to look for an underlying cause and consider the combined oral contraceptive pill (COC) or a levonorgestrel intrauterine system (LNG-IUD), rather than relying on indefinitely.Stomach and bowel: taken with food and for short periods, the risk is low; long-term or high-dose use can damage the stomach lining and cause ulcers.Kidneys: with prostaglandins suppressed, the small arteries leading into the kidney's filters narrow, and the glomerular filtration rate (GFR, how fast the kidneys filter the blood) drops for a while. People with chronic kidney disease, dehydration or high blood pressure, and older people, should use them with caution.Heart and blood vessels: in the US, every NSAID label carries a boxed warning about cardiovascular and gastrointestinal risk, and the risk rises with dose and duration; short-term use around a period carries very low risk.Clotting: blocking COX-1 lowers thromboxane A2 (TXA2) in platelets and increases the tendency to bleed; but short-term use during a period has been reported to cut menstrual blood loss by 20–30%, a double benefit.Absolute contraindications: an active stomach or bowel ulcer, severe kidney impairment, asthma triggered by aspirin, and allergy to NSAIDs.Relative contraindications: pregnancy (especially late pregnancy), breastfeeding (short courses are fine), and taking anticoagulants.
In practice · Other options when NSAIDs fall short
When do not work or cannot be usedHeat: in the Akin 2001 randomized trial in *Obstetrics & Gynecology*, a continuous low-heat patch on the abdomen relieved pain as well as ibuprofen did; using both together did not give more overall relief, but relief came sooner. At home, heat of 40–44 °C for 4–6 hours at a time is common; the trial used low-heat patches worn for most of the day.Transcutaneous electrical nerve stimulation (TENS): small electrodes on the skin deliver a weak current that interferes with pain signals; worth a try for recurring pain, though the evidence is limited.Hormonal options:The combined oral contraceptive pill (COC): it suppresses ovulation and thins the lining, so fewer prostaglandins are made and period pain can drop by 70–90%.A levonorgestrel intrauterine system (LNG-IUD, such as Mirena): it releases a progestin locally inside the uterus; over 5 years heavy bleeding can fall by 70–95%, and period pain eases markedly.Suited to: people for whom NSAIDs do not work, who also need contraception, or who have both heavy periods and pain.Gonadotropin-releasing hormone (GnRH) agonists with add-back hormones: for severe endometriosis or adenomyosis, decided by a gynecologist.Surgery: for very severe endometriosis, large fibroids or adenomyosis, a laparoscopic assessment can be considered.
Some common misunderstandings
NSAIDs stop your period: wrong. NSAIDs do not affect ovulation or the cycle, and they actually make bleeding slightly lighter.Taking NSAIDs long term is addictive: wrong. NSAIDs are not opioids and do not cause addiction.Period pain is a good thing because it detoxifies: wrong. Period pain is prostaglandins in overdrive, and it expels no toxins.Period pain goes away after having a baby: partly true. Some primary dysmenorrhea improves after childbirth (possibly because of changes in pelvic nerves and the lining), but secondary dysmenorrhea (especially from endometriosis) may get worse.
Related stories: Fats & Omega-3 (the prostaglandin pathway), Magnesium (relaxing the uterine smooth muscle), Vitamin B6 and Vitamin D.
Clinical · When period pain hides a disease
Secondary dysmenorrhea means period pain with a structural disease behind it, and it is handled completely differently from primary dysmenorrhea.Common causes and what marks each
Endometriosis:Tissue similar to the uterine lining grows outside the uterus (on the ovaries, in the pelvis, in the pouch between the rectum and uterus and elsewhere), bleeds with each cycle, and causes inflammation and scarring that sticks organs together.The Critchley 2020 review puts it at 6–10% of women of reproductive age.Typical signs: period pain that keeps getting worse, plus pain during sex, painful bowel movements and infertility.Diagnosis is often delayed for a long time: Critchley 2020 estimates up to 7–10 years; Nnoaham 2011 measured an average of 6.7 years across ten countries.The gold standard for diagnosis is laparoscopy with pathology; imaging (transvaginal ultrasound and MRI) can show deep lesions and endometriosis cysts in the ovaries.Adenomyosis:The lining grows into the muscle wall of the uterus, thickening it throughout or in patches.Most common in women over 30–40 who have given birth.Typical signs: period pain, heavy periods and an enlarged uterus (it can feel like early pregnancy).Diagnosis: transvaginal ultrasound and MRI (a widened junctional zone on T2-weighted images).Fibroids (leiomyoma):Benign tumors of the uterine smooth muscle.Most common after 35; in Black women they appear earlier and in greater numbers.Whether they hurt depends on where they are and how big, and varies a lot between people; the main symptom is still heavy bleeding, with period pain second.Pelvic inflammatory disease (PID): acute or chronic, usually after a sexually transmitted infection, with fever or abnormal discharge.A narrow cervix or an abnormally shaped uterus: menstrual blood cannot flow out freely.
Red flags for secondary dysmenorrhea (different from primary)
New onset: no pain before, starting only after age 25Getting worse: each month worse than the last no longer fully relieve itPain not limited to the first 1–2 days: starting a week before the period, continuing outside the period, or pain during sexOther symptoms: heavy periods, infertility, abnormal bleeding, bleeding after sex, pain when passing stool or urine
The age-25 line does not apply to teenagers: endometriosis can begin in adolescence. The American College of Obstetricians and Gynecologists (ACOG) committee opinion on dysmenorrhea and endometriosis in adolescents (issued 2018, reaffirmed 2023) advises that teenagers whose period pain stays severe despite NSAIDs or hormonal medicines should also be considered for endometriosis.
The diagnostic path
1. History, pelvic examination and a pregnancy test
2. Transvaginal ultrasound: the first-choice scan, looking at fibroids, endometriosis cysts in the ovaries, adenomyosis and the lining
3. Pelvic MRI: for deep endometriosis, complex adenomyosis and planning surgery
4. Laparoscopy with biopsy: the gold standard for endometriosis, and a chance to treat it at the same time
If period pain stays severe, NSAIDs cannot control it and it is affecting your life, see a gynecologist early. Do not let period pain is normal talk you out of it, and do not wait years to be found.
Drug treatment (under a gynecologist's guidance)
The combined oral contraceptive pill (COC): suppresses ovulation and thins the lining; a first-line choice for most endometriosis and primary dysmenorrhea.A levonorgestrel intrauterine system (LNG-IUD, Mirena): a common first-line choice for endometriosis and adenomyosis; one device lasts 5 years.Progestin medicines (by mouth, by injection or under the skin): suppress growth of the lining.GnRH antagonists (elagolix, relugolix): for moderate to severe endometriosis (approved by the US FDA in stages from 2018), combined with add-back estrogen to prevent bone loss.Surgery: conservative surgery (removing endometriosis lesions), removal of the uterus with the ovaries kept, or removal of the uterus and ovaries, depending on age, plans for children and the disease.
Chapter 4
Mood changes before a period
About 80% of women of reproductive age have had low mood, irritability, appetite changes or poor sleep in the 5–10 days before a period. The severity varies enormously, from barely noticeable to seriously disrupting daily life, and it is best seen as two levels.
Premenstrual syndrome (PMS) is the mild-to-moderate level: in the late luteal phase (5–10 days before a period) there is at least 1 mood symptom and at least 1 physical symptom, and they go away once the period starts. About 20–30% of women of reproductive age have PMS, and it does not impair the core of work or study. Diagnosing it takes a symptom diary kept prospectively over 2 cycles; recalling afterward is not reliable.
Premenstrual dysphoric disorder (PMDD) is the severe level. It has formal psychiatric diagnostic criteria, and about 3–8% of women of reproductive age meet them. It is not an abnormal hormone level; it is a brain that is unusually sensitive to normal hormone swings. If thoughts of harming yourself appear before your period, seek care immediately rather than waiting for the period to pass.
Premenstrual syndrome (PMS) is the mild-to-moderate level: in the late luteal phase (5–10 days before a period) there is at least 1 mood symptom and at least 1 physical symptom, and they go away once the period starts. About 20–30% of women of reproductive age have PMS, and it does not impair the core of work or study. Diagnosing it takes a symptom diary kept prospectively over 2 cycles; recalling afterward is not reliable.
Premenstrual dysphoric disorder (PMDD) is the severe level. It has formal psychiatric diagnostic criteria, and about 3–8% of women of reproductive age meet them. It is not an abnormal hormone level; it is a brain that is unusually sensitive to normal hormone swings. If thoughts of harming yourself appear before your period, seek care immediately rather than waiting for the period to pass.
Clinical · The diagnostic criteria for PMDD
The diagnostic criteria for PMDD (the Diagnostic and Statistical Manual of Mental Disorders, fifth edition, DSM-5): at least 5 symptoms, at least 1 of them from group A.Group A (core mood symptoms, at least 1 required):
Marked mood swings: sudden sadness or tearfulnessMarked irritability or anger, or more conflict with other peopleMarked low mood, hopelessness or self-criticismMarked anxiety, tension or feeling on edge
Group B (other symptoms, making up 5 in total with group A):
Less interest in usual activitiesDifficulty concentrating or thinkingSleepiness, tiredness or low energyMarked change in appetite, overeating or cravings for particular foodsDisturbed sleep (sleeping too much, or insomnia)Feeling out of control or overwhelmedPhysical symptoms: breast tenderness, bloating, joint or muscle pain, headache or swelling
The key conditions
Symptoms must cluster in the late luteal phase, start to improve within a few days of the period starting, and be mild or gone in the week after the period, in other words follow the hormone curve.It has to be confirmed by prospective records over 2 cycles (usually with the DRSP, a form for scoring each symptom every day).It causes clinically significant impairment (at work, in study or in relationships).It is not better explained by another mental disorder. For example, depression that worsens before a period is not PMDD; it is called premenstrual exacerbation (PME).About 3–8% of women of reproductive age have PMDD (Halbreich 2003 review), more than the public imagines; a further 13–18% have premenstrual symptoms severe enough to cause impairment and distress without reaching the number of symptoms the diagnosis requires.It is often mistaken in clinics for an anxiety disorder or bipolar disorder; the key way to tell them apart is whether the symptoms follow the menstrual cycle.
Mechanism · Normal hormones, yet mood breaks down
Mechanism (not fully worked out, but there are a few main pathways)It is not an abnormal hormone level: women with PMDD have the same blood levels of (E2) and progesterone as controls; what matters is a brain that is unusually sensitive to normal hormone swings.Allopregnanolone (ALLO), a breakdown product of progesterone, strengthens the action of -A receptors (GABA is the brain's main brake signal). It acts on the same kind of receptor as benzodiazepines and alcohol, but binds at a different site. As ALLO rises in the luteal phase, most women feel relaxed and fall asleep more easily; in women with PMDD, the same ALLO instead triggers anxiety and irritability. Bäckström 2014 calls this a paradoxical effect and notes that it follows an inverted-U relationship with concentration: very low and very high levels are fine, the middle band is where mood breaks, and the luteal phase passes right through it.The serotonin () system: studies have reported a larger luteal-phase drop in serotonin and changes in receptor density in women with PMDD; this is thought to be one reason (selective serotonin reuptake inhibitors) work.The stress axis ( axis): some studies have found a weaker hormonal stress response before the period in women with PMDD, leaving them less able to buffer stress.
Clinical · Treating PMS and PMDD
: the first-line drugs for PMDDA Cochrane review pooling many randomized trials (Marjoribanks 2013) found that SSRIs relieve premenstrual symptoms clearly better than placebo, with an effect between moderate and small; taking them only in the luteal phase or every day showed no difference in effect. The evidence was of low to moderate quality. Side effects are fairly common, most often nausea and lack of energy, and they increase with dose.Fluoxetine at 20 mg a day was the first drug approved by the US FDA for PMDD (brand name Sarafem); one of the trials behind it was Steiner's 1995 multicenter randomized trial in *NEJM*.Sertraline at 50–150 mg and paroxetine at 20–30 mg are also approved for PMDD (follow the label for the exact form and dose).Fast onset is a feature of PMDD: treating depression usually takes 4–6 weeks to show an effect, whereas PMDD responds within 1–2 cycles, which suggests a direct effect on neurotransmitters rather than slow rewiring of the brain.Two ways to take them:Continuous: every day; simple, with steady side effects.Luteal phase only: start after ovulation (around day 14) and stop on day 1–2 of the period. Fewer side effects and lower cost, and broadly similar effect to continuous dosing (Marjoribanks 2013). The Yonkers 2015 randomized trial tested an even leaner schedule, starting only when symptoms appear, but its main outcome reached only P = .06, short of statistical significance, so do not push the dosing window any later.
Other options with evidence
Cognitive behavioral therapy (): worth trying, but know where the evidence stops. The Lustyk 2009 systematic review concluded that existing trials had largely failed to show statistically significant effects of CBT, and called for more rigorous studies. It is low risk and can be combined with other approaches, but it has not been shown to beat medication.Exercise: for period pain, a Cochrane review (Armour 2019) found that regular exercise may reduce pain markedly, mostly with sessions of 45–60 minutes at least 3 times a week, but the evidence is of low quality. For premenstrual mood and physical symptoms, the Daley 2009 review found too little research to make an evidence-based recommendation. So the usual advice of moderate exercise for 30 minutes, 3–5 times a week, rests on its low risk and other benefits, not on proof that it works for PMS.Calcium, 1000–1200 mg a day (food plus supplement): in the Thys-Jacobs 1998 randomized trial (n=466), by the third cycle of treatment the calcium group's total symptom score had fallen 48% from baseline, but the placebo group's fell 30% too. Only the two numbers together show the real size of the effect; printing only the 48% is exactly the cut that supplement marketing favors.Getting enough vitamin D: in the Nurses' Health Study II (Bertone-Johnson 2005, a case-control study nested in a large cohort), women with the highest total vitamin D intake and the highest calcium intake from food were less likely to develop PMS over the following ten years. This is an association that was observed; it does not show that the nutrients caused the difference.Vitamin B6, 50–100 mg a day: a systematic review by Wyatt 1999 in the *BMJ* concluded that up to 100 mg a day is likely to help premenstrual symptoms, but most of the trials it included were of low quality.Less alcohol, caffeine and salt in the luteal phase: helps with breast tenderness, irritability and swelling.Magnesium, 200–400 mg a day: may slightly improve swelling and mood. ⚠️ The study behind this, Quaranta 2007, was a pilot study using a fixed 250 mg modified-release tablet; 200–400 is a range based on common products, not one the study tested. The top of the range is above the tolerable upper intake level () for supplemental magnesium, so doses that high should be taken under medical guidance.Chasteberry (Vitex agnus-castus): some small randomized trials were positive, but product standardization is poor.
Ineffective or weak
Progesterone supplements (by mouth, vaginal or by injection): a Cochrane review (Ford 2012) found only 2 eligible trials, and its verdict was that they did not show that progesterone is an effective treatment for PMS, nor that it is not. So it is unsupported rather than disproven; but the intuition that PMS comes from low progesterone, so top it up still has no trial behind it.Evening primrose oil: several randomized trials were negative.Commercial heat-clearing herbal mixtures (traditional Chinese medicine): not standardized, and they may contain undeclared ingredients with hormonal activity.
Acute suicide risk (red flag)
Women with PMDD have a clearly higher risk of suicidal thoughts and behavior. A nationally representative survey (Pilver 2013) compared women with PMDD with women with no premenstrual symptoms at all; the (OR, roughly how many times as likely) were 2.22 for suicidal thoughts, 2.27 for suicide plans and 2.10 for suicide attempts.The risk concentrates in the 1–3 days before the period.Any thoughts of self-harm: see psychiatry immediately, not "it'll pass when the period comes".
PMS and PMDD are not a character flaw, not losing control of your emotions, and not periods being too harsh. They reflect differences in how sensitive the nervous system is to normal hormone swings. That SSRIs work so fast in PMDD is itself one piece of evidence for this mechanism.
Chapter 5
Before, during and after a period
What to do before, during and after a period differs, because the hormone curve and the prostaglandin peak fall at different times. Before a period, the aim is to prevent cramps and cushion mood: if you have a history of period pain, start the painkiller before the pain does. The first days of a period hurt most, and heat plus light to moderate activity suit that better than lying still all day. After the period is the window for replacing iron, recovering and training harder.
The default is to keep moving, not mandatory rest. Common period tonics (brown-sugar water, donkey-hide gelatin, red dates) contain very little iron, far short of what replacing it takes; if your periods are heavy and you always feel tired, what you need is a test and iron taken under a doctor's guidance.
The default is to keep moving, not mandatory rest. Common period tonics (brown-sugar water, donkey-hide gelatin, red dates) contain very little iron, far short of what replacing it takes; if your periods are heavy and you always feel tired, what you need is a test and iron taken under a doctor's guidance.
In practice · Prevention 7–10 days before a period
This chapter condenses the mechanisms above into checklists for before, during and after a period that you can follow, ordered by strength of evidence and by timing.🌙 7–10 days before a period (luteal phase: preventing cramps and cushioning premenstrual symptoms)
Preventive (for people with a history of moderate to severe period pain): start 1–2 days before the period is due, not after the pain begins (by then the prostaglandins have already been released in large amounts).Ibuprofen 400 mg every 6 hours for 2–3 daysNaproxen 250–500 mg every 8–12 hours for 2–3 daysTake with food and stay within the daily limit on the labelMagnesium, 200–400 mg a day (magnesium citrate or glycinate), from the luteal phase to day 2 of the period: the rationale is that magnesium helps relax smooth muscle and regulates NMDA receptors (a type of excitatory nerve receptor). The Peikert 1996 randomized trial that is often cited tested magnesium for preventing migraine, not for period pain or premenstrual syndrome. The top of the range is above the tolerable upper intake level () for supplemental magnesium, so doses that high should be taken under medical guidance.Vitamin B1 (thiamine), 100 mg a day: Gokhale 1996 reported a large effect in a randomized trial of adolescent girls in India, but it is the only such trial and has not been replicated. A Cochrane review (Pattanittum 2016) rated the evidence for supplements in period pain as low or very low quality overall.Vitamin B6, 50–100 mg a day: a systematic review by Wyatt 1999 in the *BMJ* concluded that it may help premenstrual symptoms, but most of the trials were of low quality. Do not take more than 100 mg a day long term (it carries a risk of peripheral nerve damage; see the Vitamin B6 story).Omega-3 ( plus ), 1–2 g a day: in a crossover trial by Rahbar 2012 in young women in Iran, one omega-3 capsule a day eased period pain after three months and reduced the ibuprofen needed; but the Cochrane review (Pattanittum 2016) judged the evidence for fish oil to be very limited (see the Fats & Omega-3 and Fish Oil stories).Ginger (Zingiber officinale), 250 mg four times a day for 3 days from the first day of the period: Ozgoli 2009 compared it in female university students in Iran and found ginger relieved pain as well as mefenamic acid and ibuprofen. It is a single trial.Calcium, 1000–1200 mg a day (mainly from food), and enough vitamin D: in the Nurses' Health Study II (Bertone-Johnson 2005), women with the highest total vitamin D intake and the highest calcium intake from food were less likely to develop PMS later; this is an observed association.Less salt, alcohol and coffee in the luteal phase: reduces swelling, breast tenderness and irritability.Enough sleep, less blue light from screens: short sleep in the week before a period makes premenstrual symptoms worse.Keep exercising: do not stop because of luteal-phase tiredness; 30 minutes of moderate aerobic exercise lifts mood and eases bloating.
In practice · Managing pain on days 1–3
🩸 Days 1–3 of a period (when pain is worst: active management)If you started 1–2 days before the period, keep going on schedule; this is the single most important step.Heat (40–44 °C, 4–6 hours at a time, 1–2 times a day): in the Akin 2001 randomized trial, a low-heat patch relieved pain as well as ibuprofen, and together with ibuprofen it worked sooner.A hot-water bottle, stick-on heat pads or a heated belt all work (worth having if you get period pain often)Watch for low-temperature burns, especially while asleepDrinking enough and moving moderately (light to moderate intensity) beats lying still all dayA Cochrane review (Armour 2019) found that regular exercise may reduce period pain markedly, but the evidence is of low quality; and those trials had women exercise regularly across the whole month, some asking them to pause during their period, so they did not directly test exercising on period days.No exercise during your period is a misconception; a better rule is avoid all-out effort and stop if it feels wrong, not a ban on exercise.Walking, yoga, stretching and moderate aerobic exercise are all fine.Iron plus vitamin C (for heavy periods or anemia): start 1–2 days after the period ends, with 30–60 mg of iron a day taken with 50–100 mg of vitamin C (see the Iron and Vitamin C stories).Alternate-day iron (Stoffel 2017): in women with low iron stores, taking iron every other day gave higher total absorption than taking it daily, because the hepcidin (the hormone that controls iron absorption from the gut) that rises after each dose needs time to fall back.Plain, easily digested food: the prostaglandin PGE2 speeds up the gut, and some women get diarrhea during their period; go easy on spicy food and coffee, and keep eating fiber as usual.Being gentle with yourself is not superstition: from the late luteal phase to the first 2 days of the period, cortisol regulation is weaker and pain sensitivity higher, so avoiding high-stakes decisions, big arguments and draining social events is reasonable.
In practice · After a period, and what tonics are worth
🌱 1–2 weeks after a period (follicular phase: repair and training harder)Iron: if your periods are heavy or you are iron deficient, take iron together with vitamin C, and not at the same time as calcium tablets, tea, coffee, milk or antacids (leave at least 2 hours between them).A good window for strength training: in the Wikström-Frisén 2017 trial, the group that concentrated leg training in the follicular phase gained clearly in squat, countermovement jump and hamstring peak torque over four months, while the group that concentrated it in the luteal phase did not. Note that it tested how training is arranged around the cycle, not which day you are stronger, and it is one small trial. If you want a strength record or high-intensity interval training (), this is a good time.Enough protein: a common recommendation is 1.2–1.6 g/kg a day, which is the amount that goes with the strength training above. The uterine lining rebuilds itself each month under the control of hormones and does not need extra protein.Review your records and adjust the plan for the next cycle: note how bad the pain got, how heavy the flow was and any red flags, and decide whether next cycle's should start 24 or 48 hours ahead.Recheck : if heavy periods keep recurring, check ferritin and hemoglobin every 6 months to catch and treat problems early.
The truth about some common "period tonics"
Brown-sugar water (a widespread custom in Chinese-speaking communities): mostly sugar, with very little iron (about 0.5 mg/100 g), so it is essentially useless for replacing iron; the warm feeling comes mainly from the hot water itself. It does no harm, but do not let it replace real sources of iron.Donkey-hide gelatin (ejiao) and red dates (called blood tonics in traditional Chinese medicine): ejiao has extremely little iron (about 0.2 mg/g), and its protein is mostly collagen; red dates contain about 2 mg of iron per 100 g, fine as food but nowhere near a treatment dose.Period detox teas, period-regulating pills and brown-sugar ginger teas: no evidence behind them; some products contain unregulated ingredients (some laxatives, herbal ingredients with hormonal activity).Chocolate and dark chocolate (≥ 70%): contain magnesium and polyphenols and are relaxing to eat, with a little research support, but they are not a treatment.Womb-warming patches (a consumer product in Chinese-speaking markets): they heat up by oxidizing iron powder, physically the same as a hot-water bottle (40–44 °C), not herbal energy. The heat genuinely helps; the name is misleading, but the product is not necessarily bad.
Related stories
Fats & Omega-3 and Fish Oil: the prostaglandin pathway, and sources and forms of and Magnesium: relaxing uterine smooth muscle, and migraine (Peikert 1996)Vitamin B6: Wyatt's 1999 review on PMS, and the upper-limit warningThiamin: the Gokhale 1996 trial on period painVitamin D and Calcium: the Bertone-Johnson 2005 PMS studyIron and Vitamin C: replacing iron after heavy periods, and alternate-day iron (Stoffel 2017)Protein: protein during post-period training
In practice · Exercising during a period, and how
Can I exercise during my period? is one of the most misreported health questions. First the evidence, then a template you can follow.The short answer: yes, and for most women it helps
A Cochrane review (Armour 2019): regular exercise may reduce the severity of period pain markedly, but the evidence is of low quality. The exercise in the trials was done across the whole month, and some trials had women pause during their period, so what it directly supports is regular exercise in general, not a test of exercising on period days specifically. The usual advice of moderate exercise for 30 minutes, 3–4 times a week, is a practical amount given in that direction.The Daley 2009 review: there is too little research on exercise for premenstrual syndrome (PMS), and the author judged that no evidence-based recommendation could be made. So the Cochrane review above covers period pain and does not extend to PMS.The Yonglitthipagon 2017 randomized trial: a yoga program reduced period pain in primary dysmenorrhea and improved fitness and quality of life. ⚠️ It did not measure PMS, so do not treat it as evidence that yoga treats PMS.
How to train: sorted by intensity
What most people can do during a period
Walking or jogging: 30–45 minutes at 50–70% of maximum heart rateYoga or Pilates: focus on stretching and breathing, and skip deep inversions (harmless in theory, but some women find them uncomfortable)Swimming: use a menstrual cup or tampon; it does not contaminate the pool (water pressure makes it hard for blood to flow out)Dance or low-intensity intervals: as toleratedRegular strength training: pay attention to how you feel, and you can cut the load by 5–10%
Adjust to how you feel
Going for a strength record, or high-intensity interval training (): women with bad pain on days 1–2 can put it off until day 3 or laterLong runs (over 15 km): depends on anemia and painCrossFit-style extreme training: as tolerated
Best skipped for now when pain is severe
If period pain is severe and cannot control it, do not push throughDeep inversions such as headstands and shoulder stands: some women feel unwell on days 1–2Hard sweating in hot environments (hot yoga, sauna): you are already losing fluid during a period and have less room to regulate heat, so be careful
A few principles
1. Listen to your body, not slogans: if you are tired, lower the intensity; there is no need to force a personal best even on my period.
2. Warm up well and have your period products ready: for heavy activity, menstrual cups and tampons suit better than pads.
3. Water and electrolytes: with fluid lost to both the period and sweat, topping up sodium and potassium can make sense.
4. Skip very cold showers after exercise: not superstition; blood vessels in the skin react a little more strongly during a period, and there is no need to add strain.
Complete bed rest during a period is a mistaken old tradition
Sitting or lying down for long stretches may worsen congestion in the pelvis, and period pain can get worse.Light to moderate exercise increases blood flow to the uterus and releases endorphins; for some women it feels better than a painkiller.Limiting exercise is warranted only for severe period pain, red-flag signs, or heavy bleeding with anemia.
Periods and high-level athletes (RED-S, low energy availability)
Relative energy deficiency in sport (RED-S, a concept developed from the female athlete triad): when energy intake cannot keep up with training, it can lead to functional hypothalamic amenorrhea (FHA), lower and stress fractures.Irregular cycles, missed periods or very light periods during serious training are not a sign of training going well; they are a warning of too little energy.What to do: eat more, train less, get nutrition advice, and see gynecology and endocrinology when needed.
Exercise during a period varies from person to person, but the default should be to keep moving rather than lying down to recover. To choose the intensity, go by how you feel, have your gear ready ahead of time, and do not let the old slogan periods need rest tie you down.
yonglitthipagon-2017-yoga-dysmenorrhea
Chapter 6
Old period rules and when to get care
Most of the period taboos passed around the Chinese-language internet and handed down by older relatives have no evidence behind them; like all folklore, a few do hold up. No washing your hair, no cold water, no swimming, menstrual blood as a detox: none of these stand up under modern living conditions.
Heat on the abdomen helps, not because every trace of cold must be avoided, but because warmth itself relieves pain; less coffee and alcohol before a period, and getting iron checked early when periods are heavy, are the advice that holds. It is also worth knowing when to move from looking after yourself to seeing a doctor; and heavy bleeding with dizziness or a racing heart, a positive pregnancy test with severe abdominal pain, bleeding after menopause, or a high fever with abnormal discharge means going to the emergency department.
Heat on the abdomen helps, not because every trace of cold must be avoided, but because warmth itself relieves pain; less coffee and alcohol before a period, and getting iron checked early when periods are heavy, are the advice that holds. It is also worth knowing when to move from looking after yourself to seeing a doctor; and heavy bleeding with dizziness or a racing heart, a positive pregnancy test with severe abdominal pain, bleeding after menopause, or a high fever with abnormal discharge means going to the emergency department.
Myth · Period taboos with no evidence behind them
Most of the period taboos passed around the Chinese-language internet and handed down by older relatives have no evidence behind them; but like all folk wisdom, a few really do hold. Here they are, one at a time.🚫 No evidence (safe to ignore)
No washing your hair during a period: no research supports it. Washing with warm water and drying promptly has no causal link to headaches or head-wind (a traditional notion of cold entering the head). The taboo comes from an era without water heaters or hair dryers, when avoiding a chill made sense; it does not apply now.No cold water or cold drinks during a period: a cold womb is not a medical concept. The uterus has no direct contact with what is in the stomach and bowel; cold food and drink are warmed to body temperature before they even reach the intestine, and there is no direct causal link to period pain. The few observational studies have not confirmed a link between cold drinks and period pain either. (Warm water feels nicer and makes it easier to drink more, which is a real benefit, but it has nothing to do with the taboo.)No swimming during a period: a menstrual cup or tampon prevents leaks; water pressure makes it hard for blood to flow out; and with pool disinfection and a shower afterward, there is no hygiene problem.No sex during a period: it is not medically forbidden and comes down to comfort and choice; you still need contraception (pregnancy from sex during a period is rare but possible) and protection against infection (the cervix is slightly open during a period, so the infection risk is slightly higher in theory, though the real difference is very small).No dental extractions or surgery during a period: emergency surgery goes ahead regardless; planned major surgery is usually scheduled outside the period, but the reason is less bleeding to deal with and more comfort for the patient, not harm to your vital energy.Periods detoxify, menstrual blood is dirty: menstrual fluid is lining tissue, blood and mucus, with no toxins in it.Red dates, donkey-hide gelatin and brown sugar replenish blood: see the analysis of these tonics in the chapter Before, during and after a period; they are mainly cultural symbols, with far less iron than a treatment dose.Fruit, vegetables and cold dishes are cooling during a period: no evidence.No photos, no ancestor rites and no temple visits during a period: questions of culture and taboo, unrelated to physiology.
Myth · Which old sayings are partly right
🤔 Partly right (though not for the reasons the legend gives)Keep warm during a period: partly right. Warmth on the abdomen and lower back (40–44 °C for 4–6 hours) is an effective drug-free way to relieve pain (the Akin 2001 randomized trial); but there is no need to avoid every trace of cold; what helps is targeted heat plus a reasonably warm environment.No hard exercise during a period: partly right. The rule is as tolerated, not no exercise (see the exercise section of the chapter Before, during and after a period).Immunity is weaker during a period: partly right. Immune regulation shifts subtly in the luteal phase (helper T cells lean slightly toward the Th2 type), and some infections such as herpes simplex are more likely to flare in the week before a period; but this is nowhere near serious immune weakness, and no special isolation is needed.Emotions are more sensitive during a period: see the chapter Mood changes before a period; this is real neuroscience, not melodrama.
✅ Genuinely right
Enough sleep, and less coffee and alcohol in the week before a period: short sleep before and during a period worsens premenstrual symptoms and period pain, and both data and mechanism support this.Plenty of water, and some warm drinks: not to avoid cold, but to replace lost fluid, and because it feels good. plus heat, with the tablets started 1–2 days early: an evidence-based combination for pain relief.With heavy periods, check and take iron early: heavy periods are normal is wrong; heavy periods are the commonest, and most correctable, cause of iron-deficiency anemia.
Red flag · When to see a doctor, when to go to the ER
⬆️ When should you step up to medical care?Most period problems (70–80%) can be handled with , heat and lifestyle, but there are some clear points at which to step up:
Fine to handle yourself (over-the-counter drugs and nutrition changes, no appointment needed)
Moderate period pain that affects 1–2 days of workA regular cycle, normal flow and no red flags
See gynecology this month
NSAIDs do not work or cannot be used: see a gynecologist about the combined oral contraceptive pill (COC) or a levonorgestrel intrauterine system (LNG-IUD)Heavy periods (a PBAC score above 100, or the feeling of soaking through in 1 hour): see gynecology and have your iron checkedPeriod pain lasting 6 months or more and getting worse: be screened for endometriosisA persistently abnormal cycle (shorter than 21 or longer than 35 days for ≥ 3 cycles in a row): see endocrinology and gynecologyPeriods plus easy bruising or nosebleeds: be screened for a clotting disorder (von Willebrand disease, vWD)Premenstrual symptoms that seriously affect work, or thoughts of suicide: a joint psychiatry and gynecology assessment for PMDD
Go to the emergency department (today):
Heavy bleeding with dizziness, a fast heart rate or pallorSevere abdominal pain with a positive pregnancy test: seek care immediately to rule out an ectopic pregnancyAny vaginal bleeding after menopauseHigh fever with abnormal discharge (PID)
Medical options (under a gynecologist's guidance)
The combined oral contraceptive pill (COC): suppresses ovulation and thins the lining; period pain can drop by 70–90%, heavy bleeding also eases, and it works as contraception.Risk: blood clots in the veins (VTE), especially in smokers, people over 35 and people with migraine with auraSuited to: period pain, needing contraception, endometriosis, polycystic ovary syndrome ()A levonorgestrel intrauterine system (LNG-IUD, such as Mirena or Kyleena): releases a progestin locally inside the uterus and thins the lining; heavy bleeding can fall by 70–95% and period pain eases, with 5 years of contraception. Suited to heavy periods, period pain, endometriosis and adenomyosis, and a first choice for many people.A progestin on its own: used in some situations.GnRH antagonists (elagolix, relugolix): for moderate to severe endometriosis and fibroids; they lower estrogen for a limited time, with add-back hormones to prevent bone loss.Tranexamic acid: a drug that reduces bleeding during heavy periods (taken during the first 5 days of the period); it can cut blood loss by 30–50% and does not affect the cycle.Surgery: only for the most severe endometriosis, large fibroids, adenomyosis and heavy bleeding that nothing else controls; removing the uterus is the last resort.
In practice · Tracking, and how others can help
Tools for tracking your cycle (privacy first)Apps: Clue, Flo, Apple Health (prefer on-device storage), or Garmin's health sync.A privacy warning: since Roe v. Wade was overturned in the US, there have been cases in some states of menstrual data being obtained by courts. Prefer apps with on-device storage, end-to-end encryption and servers outside the US.Worth recording over the long term: the first day of each period, cycle length, flow and pain, abnormal bleeding, and a score for premenstrual symptoms.A record of 3–6 months tells more than any single hormone test, and it is the strongest material to bring to a gynecology appointment.
For readers who do not menstruate
Periods are not a women's matter; they are health knowledge everyone should have.When partners, fathers, friends and colleagues know the basics and can recognize the red flags, she no longer has to carry that information gap alone.Just put up with it and period pain is normal are the two things this generation of women has heard most; after reading this, perhaps you will say them one time fewer.
Periods are not a taboo subject. They are a health matter that can be measured, improved and, when needed, escalated. Putting up with it was the price paid in the past; understanding, tools and early checks are the choice now.
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