Amenorrhea: Meaning, Primary and Secondary Causes, Tests, Treatment & Fertility

Amenorrhea means having no periods. Doctors call it primary amenorrhea when a girl has not had her first period by age 15, and secondary amenorrhea when a woman who used to have periods has none for 3 months in a row (or 6 months if her cycles were already irregular). The most common cause is pregnancy; after that, PCOS, thyroid problems, high prolactin, and low weight, stress or heavy exercise lead the list. Absent periods are a sign to find the cause, not an illness on their own, and most causes can be treated. At Yaal Fertility Centre in Chennai, Dr. Rukkayal Fathima and our team see women with missed periods every day and help them get a clear answer.

What Does Amenorrhea Mean?

The word comes from Greek and simply means "no monthly flow". It is spelt amenorrhoea in British and Indian medical writing and amenorrhea in American English; both mean the same.

A regular period is a sign that the brain, the ovaries and the womb are all talking to each other properly. The hypothalamus in the brain sends a signal to the pituitary gland, which releases hormones (FSH and LH) that make the ovaries grow an egg and produce estrogen and progesterone. These hormones build up the womb lining, and when no pregnancy happens, the lining sheds as a period. If any link in this chain is disturbed, periods stop. Our guide to the phases of the menstrual cycle explains the chain in more detail.

Amenorrhea, Irregular Periods and a Late Period

These are often confused, but they are not the same:

This guide focuses on periods that have stopped completely or never started.

Primary vs Secondary Amenorrhea

Primary Amenorrhea

A girl should be checked if:

• She has not had a period by age 15, even if breasts and body hair have developed normally.
• She has no signs of puberty at all by age 13, such as breast development.
• Her breasts started developing more than 3 years ago and periods have still not begun.
• She has monthly tummy pain but no bleeding, which can mean blood is trapped behind a blockage.

Primary amenorrhea is uncommon. Many girls in their mid-teens are simply late developers, often with a family history of late periods, but checking early avoids missing a treatable cause.

Secondary Amenorrhea

This is far more common. It applies when a woman who has had periods before has none for:

• 3 months in a row, if her periods used to be regular, or
• 6 months in a row, if they were already irregular.

Missing one period is not amenorrhea. Missing three is a reason to see a doctor, even if you feel well.

What Causes Amenorrhea?

Natural Reasons Periods Stop

Some causes are completely normal:

• Pregnancy, the most common cause of a missed period in any woman who is sexually active. Always rule this out first, even if you use contraception.
• Breastfeeding, which often holds periods off for months.
• Menopause, usually in the late 40s or early 50s. Menopause is confirmed after 12 months without a period.
• Hormonal contraception. Some pills, the hormonal coil, the implant and the injection can make periods very light or stop them. This is expected and not harmful. After stopping the pill, periods sometimes take a few months to return.

Causes of Primary Amenorrhea

When periods never start, the reason is usually in one of three places.

• Genes and chromosomes. Turner syndrome, where one X chromosome is missing or altered, is the most common example; the ovaries do not develop properly and do not make enough estrogen. Other rare chromosome conditions also affect how the ovaries or womb form.
• How the womb and vagina formed. In MRKH syndrome, the womb and upper vagina do not develop, although the ovaries work normally and puberty looks normal. A hymen with no opening or a band of tissue across the vagina can block the flow, causing monthly pain without bleeding. These blockages are fixed with a small operation.
• Brain signals. Conditions that affect the hypothalamus or pituitary, including being very underweight, intense sport from a young age, or rare inherited conditions, can delay puberty.

Many causes of secondary amenorrhea listed below, such as PCOS, thyroid problems and high prolactin, can also delay a first period.

Causes of Secondary Amenorrhea

PCOS

Polycystic ovary syndrome is the most common hormonal cause of absent or very infrequent periods in women of childbearing age in India. Hormone imbalance and insulin resistance stop eggs from maturing and releasing, so the cycle stalls. Women with PCOS may go months without a period, then have a heavy one. Read our full guide to PCOS and fertility.

Long gaps between periods in PCOS are not just an inconvenience. Without regular shedding, the womb lining can build up and thicken over time, so doctors aim to make sure a woman with PCOS has a bleed at least every three months or so, or that the lining is protected with treatment.

Thyroid Problems

Both an underactive thyroid (hypothyroidism) and an overactive one (hyperthyroidism) can make periods irregular or stop them. Thyroid problems are common in Indian women and are easy to check with a blood test. Once thyroid levels are corrected with treatment, periods usually return. See our guide to thyroid and fertility.

High Prolactin

Prolactin is the hormone that makes breast milk. When it is high outside pregnancy and breastfeeding, it blocks the signals that start ovulation. Causes include a small, non-cancerous growth in the pituitary gland, an underactive thyroid and some medicines. Milky discharge from the nipples is a classic sign, though not everyone has it. Our guide to hyperprolactinemia covers this in depth.

Hypothalamic Amenorrhea: Low Weight, Over-Exercise and Stress

When the body senses that it does not have enough energy, the hypothalamus turns down the signals to the ovaries to save energy. This is called functional hypothalamic amenorrhea. It is common and often missed.

Triggers include:

• Low body weight or losing a lot of weight quickly, including through crash diets.
• Intense exercise without eating enough to match it, seen in athletes, dancers and people training hard at the gym or for marathons.
• Eating disorders such as anorexia.
• Severe or long-lasting stress, such as exams, bereavement or a major life change.
• Serious illness or long recovery from one.

Often it is a combination: a woman who is working long hours, sleeping poorly, running daily and eating less than she needs. The body is not broken; it is protecting itself. Periods usually return once energy intake rises, exercise is moderated and stress eases, though this can take several months.

Our guide to hormonal imbalance symptoms in women explains how these hormone systems affect each other.

Premature Ovarian Insufficiency

In POI, the ovaries stop working normally before age 40. Periods become irregular and then stop, and estrogen falls, causing hot flushes, night sweats, poor sleep and vaginal dryness. Causes include genetic factors, autoimmune conditions, and past chemotherapy, radiotherapy or ovarian surgery, but often no cause is found. Ovarian function can come and go, so a small number of women with POI still conceive naturally. Read about premature ovarian failure and fertility options.

Asherman Syndrome

If the inside of the womb is scarred, the lining cannot grow and shed, so periods become very light or stop, even though hormones are normal. This usually follows a D&C (scraping of the womb), surgery after a miscarriage or delivery, or a womb infection. In India, genital tuberculosis is another cause of scarring. Learn more in our guide to Asherman syndrome.

Medicines and Other Causes

• Medicines that can raise prolactin or stop periods include some antipsychotics, some antidepressants, some anti-sickness and acidity medicines, and certain blood pressure drugs. Never stop a prescribed medicine on your own; talk to the doctor who prescribed it.
• Long-term illnesses such as poorly controlled diabetes, kidney or liver disease, or coeliac disease.
• Other hormone conditions, such as problems with the adrenal glands.
• Rarely, a pituitary problem after heavy blood loss in childbirth.

Symptoms That Can Come With Absent Periods

The main symptom is no bleeding, but other signs give clues to the cause:

• Acne, oily skin, extra hair on the face or body, or scalp hair thinning point towards PCOS.
• Milky nipple discharge, headaches or blurred side vision point towards high prolactin.
• Hot flushes, night sweats, vaginal dryness and low mood point towards low estrogen, as in POI or hypothalamic amenorrhea.
• Tiredness, weight change, feeling cold or palpitations point towards a thyroid problem.
• Monthly pelvic pain without bleeding can mean blood is trapped, or scarring inside the womb.

Make a note of these before your appointment, along with when your last period was.

No Periods for 3 Months: What to Do

If you have missed three periods in a row:

1. Take a home pregnancy test if there is any chance of pregnancy. Use early-morning urine.
2. Think about recent changes: weight loss or gain, new exercise, stress, new medicines, stopping the pill, or any womb procedure.
3. Book a check-up with a gynaecologist, even if the test is negative and you feel fine.
4. Bring your history: dates of your last few periods, any symptoms above, medicines and past surgeries.
5. Do not start hormone tablets to "bring on" a period without a diagnosis. A withdrawal bleed may make you feel reassured but does not fix the cause.

How Is Amenorrhea Diagnosed?

Tests follow a step-by-step order so that common, simple causes are found first.

History and Examination

Your doctor will ask about your periods, weight, diet, exercise, stress, medicines, past surgery and family history. A general check includes height, weight and BMI, blood pressure, and signs such as acne, hair growth or nipple discharge. For a teenager, the doctor also checks breast and body hair development.

Blood Tests

Blood tests are often timed for early in the cycle when cycles exist, but with amenorrhea they can usually be done on any day.

Ultrasound Scan

A pelvic ultrasound checks the womb, its lining and the ovaries. It can show polycystic-looking ovaries, a thin lining in low-estrogen states, signs of scarring, or, in primary amenorrhea, whether the womb has formed.

Further Tests When Needed

• Progesterone challenge: a short course of progesterone is given. A bleed afterwards shows that there is enough estrogen and the passage is open. No bleed points towards low estrogen or scarring.
• MRI of the pituitary if prolactin is high or there are headaches or vision changes.
• Hysteroscopy, a thin camera into the womb, if Asherman syndrome is suspected. It can also treat the scarring.
• Chromosome test (karyotype) for primary amenorrhea or POI at a young age.
• Bone density scan if periods have been absent for a long time.

Amenorrhea Treatment

Treatment depends on the cause and on your goals, whether that is regular periods, protecting your health, or getting pregnant.

Treating the Cause

• PCOS: weight management where relevant, regular activity and a balanced diet, plus medicines to regulate periods or improve insulin resistance. The pill or cyclical progestogen is often used to protect the lining when not trying to conceive.
• Thyroid problems: thyroid medicine to bring levels back to normal, after which periods usually return.
• High prolactin: medicine to lower prolactin, which usually restores ovulation. A pituitary growth rarely needs surgery.
• Hypothalamic amenorrhea: eating enough to match activity, regaining weight if underweight, cutting back intense exercise and managing stress. A dietitian and, where needed, a counsellor are a key part of care.
• POI: hormone replacement therapy (HRT) until the usual age of menopause, to replace estrogen and protect the bones and heart. HRT is not a contraceptive.
• Asherman syndrome: hysteroscopic surgery to remove scar tissue, followed by care to stop it reforming.
• Blockages in the vagina or hymen: a minor operation to open the passage.
• Medicine-related amenorrhea: your doctor may change the medicine if it is safe to do so.

Protecting Your Bones

Estrogen keeps bones strong. When periods are absent for a long time because estrogen is low, as in hypothalamic amenorrhea or POI, bones can thin early, raising the risk of fractures later in life. This is one reason absent periods should not be ignored, especially in young women whose bones are still building strength into their mid-20s.

Ways to protect your bones:

• Treat the cause, or use hormone treatment where your doctor advises it.
• Eat calcium-rich foods: milk, curd, paneer, ragi, sesame (ellu), greens.
• Get vitamin D from morning sunlight, and ask your doctor whether you need a supplement after a blood test.
• Do weight-bearing exercise such as walking and strength training, in moderation.
• Avoid smoking and excess alcohol.

Protecting the Womb Lining

When estrogen is present but periods are absent, as often happens in PCOS, the lining is exposed to estrogen without progesterone and can thicken over time. Regular hormone treatment that brings on a bleed, or a hormonal coil, protects against this.

Amenorrhea and Fertility

Without periods, there is usually no ovulation, and without ovulation, pregnancy cannot happen naturally that month. The encouraging part is that most causes of amenorrhea are treatable, and many women go on to conceive.

Getting Pregnant With Amenorrhea

• PCOS: lifestyle changes and ovulation-inducing tablets often restore ovulation. If these do not work, injections, IUI or IVF are options. See PCOS and fertility.
• High prolactin or thyroid problems: correcting the hormone level often brings back ovulation without further fertility treatment.
• Hypothalamic amenorrhea: restoring weight and energy balance is the first step. If periods do not return, carefully monitored hormone treatment can trigger ovulation.
• Asherman syndrome: after the scarring is treated, many women can conceive, though the lining needs close monitoring.
• POI: natural pregnancy is possible but uncommon. IVF with donor eggs is the most reliable option for many women. Talk to a specialist early.

You Can Ovulate Before a Period Returns

When periods are coming back, ovulation happens about two weeks before the first period. This means it is possible to get pregnant before you have had a period at all. If you do not want to conceive, use contraception even while periods are absent unless your doctor has told you otherwise.

When to Seek Fertility Advice

If you have amenorrhea and want to become pregnant, do not wait the usual 12 months of trying. Since ovulation is not happening, a female fertility evaluation is worth arranging straight away so the cause can be treated and ovulation restored.

When to See a Doctor

See a gynaecologist if:

• You are 15 and have not had a period, or 13 with no signs of puberty.
• You have had no period for 3 months after regular cycles, or 6 months after irregular ones.
• Your periods stopped after a D&C, miscarriage surgery or delivery.
• You have milky nipple discharge, headaches or vision changes.
• You have hot flushes or night sweats under 40.
• You have lost a lot of weight, are exercising very hard or are struggling with eating.
• You want to get pregnant and are not having periods.