What is amenorrhea?
Amenorrhea is the medical word for absent periods. Primary amenorrhea means you haven't had a first period by age 15. Secondary amenorrhea means periods stop for 3 months or more after being regular, or 6 months if they were irregular. It's a symptom, not a disease. Common causes include pregnancy, stress, low weight, intense exercise, PCOS, thyroid problems and breastfeeding.
The two types
| Primary amenorrhea | Secondary amenorrhea | |
|---|---|---|
| What it means | No first period by 15 (or within 3 years of breast development) | Periods stop for 3 months (regular cycles) or 6 months (irregular cycles) |
| How common | Rare | Much more common |
| Typical causes | Late puberty, genetic or anatomy differences, low body weight, hormone conditions | Pregnancy, stress, weight change, exercise, PCOS, thyroid, prolactin, early menopause |
Normal reasons for no periods
Not every missing period is amenorrhea in the medical sense. Periods are expected to be absent during pregnancy, often while breastfeeding, after menopause, and on some hormonal contraception (like the hormonal IUD, implant, injection or a continuous pill). These aren't a problem.
Common causes of secondary amenorrhea
- Functional hypothalamic amenorrhea: the brain pauses ovulation because of stress, under-eating, weight loss or heavy training, often a mix. It's one of the most common causes in young adults.
- [PCOS](/life-stages/pcos): ovulation happens rarely, so periods are infrequent or stop.
- Thyroid problems: both overactive and underactive thyroids can stop periods.
- High prolactin: from a small benign pituitary growth or some medications.
- Premature ovarian insufficiency: the ovaries slow down before 40. See what age periods stop.
- Scarring inside the uterus (Asherman syndrome), after some surgeries or infections.
- Medicines: including some antipsychotics, antidepressants and chemotherapy.
For a quick walk-through of everyday causes, see why did my period stop.
Why it's worth treating
Periods are a vital sign. Long stretches without them can mean low estrogen, which over time weakens bones and may affect heart health. With PCOS, going many months without a period can let the uterine lining build up, which needs managing. And some causes, like thyroid disease, need treatment in their own right.
How it's checked and treated
A doctor usually starts with a pregnancy test, questions about stress, food, exercise and medicines, and blood tests for hormones such as FSH, LH, prolactin and thyroid. Sometimes an ultrasound helps. Treatment depends on the cause: for hypothalamic amenorrhea, eating enough, easing training and reducing stress often bring periods back; for PCOS or thyroid problems, medicines can help.
You haven't had a period by 15, your periods have stopped for 3 months and you're not pregnant, or you also have headaches, vision changes, milky nipple discharge, excess hair growth or significant weight change. If food, exercise or body image feel hard to control, please reach out: support for eating disorders works, and it's often what brings periods back.
Amenorrhea and mood
Absent periods and mood are often linked. Stress and anxiety can stop periods, and low estrogen can affect mood, energy and sleep in turn. Our page on anxiety and late periods explains the link. Tracking both helps you see what changed and when, which is useful for you and your doctor.
Frequently asked questions
Is it bad to not have a period for 3 months?
It's a reason to see a doctor, not to panic. The cause is often stress, weight change or PCOS, all of which can be managed.
Can amenorrhea be reversed?
Often, yes. Hypothalamic amenorrhea usually reverses once energy intake and stress improve. Other causes respond to treatment.
Can you get pregnant with amenorrhea?
It's harder because ovulation isn't happening regularly, but ovulation can restart before a period returns, so pregnancy is still possible.
Is no period on the hormonal IUD amenorrhea?
Technically yes, but it's an expected, harmless effect of the IUD thinning the lining, not a health problem.
Sources
- Cleveland Clinic: Amenorrhea
- MedlinePlus: Absent menstrual periods, primary
- MedlinePlus: Absent menstrual periods, secondary
- Gordon CM et al. Functional Hypothalamic Amenorrhea: An Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab (2017)
This page is for information only and isn鈥檛 medical advice. If something worries you, please talk to a doctor.
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