Absence of Menstruation (Amenorrhea)

What absence of menstruation means

A menstrual period happens when estrogen and progesterone from the ovaries build up the uterine lining and then fall, causing it to shed. That cycle depends on a chain: the hypothalamus in the brain signals the pituitary gland, which signals the ovaries, which act on the uterus, with blood leaving through the cervix and vagina. A problem at any link stops periods.

There are two types:

For a full overview of the condition and its treatment, see amenorrhea.

Normal reasons periods stop

• Pregnancy: the first thing to rule out, even with contraception or irregular cycles.
• Breastfeeding: high prolactin suppresses ovulation, often for months.
• Hormonal contraception: the hormonal IUD, implant, injection and continuous pill often stop periods. After stopping the injection, periods can take 6 to 12 months to return.
• Menopause: the average age in the US is about 51. Periods become irregular in perimenopause, then stop.

Medical causes of absent periods

Brain (hypothalamus and pituitary)

• Hypothalamic amenorrhea: stress, weight loss, eating too little for the amount of exercise, and eating disorders turn down the brain signals. Common in athletes, dancers and students under pressure.
• High prolactin: from a benign pituitary tumor (prolactinoma) or medicines such as some antipsychotics. May cause milky nipple discharge and headaches.
• Thyroid disease: both underactive and overactive thyroid can stop periods.
• Serious illness, some medicines (chemotherapy, opioids), and rarely pituitary damage after severe bleeding in childbirth (Sheehan syndrome).

Ovaries

• Polycystic ovary syndrome (PCOS): the most common hormonal cause. Irregular or absent periods with acne, excess hair, and often weight gain.
• Premature ovarian insufficiency: the ovaries stop working normally before 40, causing hot flashes, night sweats and vaginal dryness.
• Turner syndrome and other genetic conditions (primary amenorrhea).

Uterus and outflow

• Asherman syndrome: scar tissue inside the uterus after a D&C, infection or surgery.
• Cervical stenosis: a narrowed cervix traps blood.
• Structural differences from birth: an absent uterus or vagina, or an imperforate hymen, where monthly cramps occur but no blood appears.

Symptoms that can come with absent periods

Amenorrhea itself is the main symptom. What comes with it often points to the cause:

• Nausea, breast tenderness, frequent urination: pregnancy
• Acne, oily skin, excess facial or body hair, hair thinning: PCOS or high androgens
• Milky discharge from the nipples, headaches, vision problems: high prolactin or a pituitary tumor
• Hot flashes, night sweats, vaginal dryness, low mood: menopause or ovarian insufficiency
• Feeling cold, tiredness, weight gain, constipation: underactive thyroid
• Weight loss, feeling hot, palpitations, tremor: overactive thyroid
• Cyclical pelvic pain without bleeding: blocked outflow or uterine scarring
• Fatigue, dizziness, low weight, stress fractures: hypothalamic amenorrhea from low energy intake

How doctors find the cause

Your doctor will ask about your cycle history, sexual activity, contraception, weight change, diet, exercise, stress, medicines, previous uterine procedures and family history. They check height, weight, blood pressure, signs of excess hair or acne, breast development and sometimes a pelvic exam.

Tests usually include:

1. Pregnancy test (urine or blood).
2. Blood tests: TSH (thyroid), prolactin, FSH and LH (ovarian function), estradiol, and testosterone if PCOS is suspected.
3. Pelvic ultrasound: to look at the ovaries and the uterine lining.
4. Progestin challenge: a short course of progesterone. Bleeding afterward shows the uterus and outflow work and there is some estrogen.
5. Further tests as needed: MRI of the pituitary if prolactin is high, karyotype (chromosome test) for primary amenorrhea, hysteroscopy for suspected scarring, and a bone density scan if periods have been absent for a long time.

Treatment

Treatment depends on the cause:

• Lifestyle-related: eating enough to match activity, regaining weight and reducing stress. Periods often return within months. Support from a dietitian or therapist helps with eating disorders.
• PCOS: combined hormonal contraception or cyclic progestin to protect the uterine lining, weight management, and ovulation induction for pregnancy.
• Thyroid disease: correcting thyroid hormone levels.
• High prolactin: dopamine agonist medicines, or changing the medicine causing it.
• Ovarian insufficiency: hormone replacement until about age 51 to protect bones and the heart.
• Asherman syndrome: hysteroscopic removal of scar tissue.
• Structural causes: surgery, for example opening an imperforate hymen.

Complications of long-term amenorrhea

• Bone loss and fractures: low estrogen thins bones, especially in young athletes and people with eating disorders.
• Endometrial hyperplasia and cancer: in PCOS, estrogen without regular progesterone can overgrow the uterine lining. Doctors aim for at least 4 bleeds a year or a progestin IUD.
• Infertility: if ovulation is absent.
• Heart and metabolic risk: linked to PCOS and early menopause.

Frequently asked questions

What are the symptoms of absence of menstruation?

The main symptom is no periods. Depending on the cause, you may also have nipple discharge, headaches, vision changes, hot flashes, vaginal dryness, acne, excess hair growth, weight changes or pelvic pain. Some people have no other symptoms at all.

How long can you go without a period before it is a problem?

See a doctor if you have not had a period for 3 months and are not pregnant, breastfeeding, using hormonal contraception or near menopause. Also see a doctor if you have not had a first period by age 15.

Can stress stop your period?

Yes. Severe stress reduces the hormone signals from the brain to the ovaries, which can delay or stop ovulation. This is called functional hypothalamic amenorrhea. Periods usually return once stress is reduced and you are eating enough, but a doctor should rule out other causes.

Can you get pregnant without having periods?

Sometimes. Ovulation happens before a period, so it is possible to become pregnant before periods return, for example after childbirth or stopping contraception. If you do not want to become pregnant, keep using contraception.

Is absence of menstruation the same as menopause?

No. Menopause is one cause of amenorrhea, confirmed after 12 months with no period, usually around age 51. Absent periods earlier in life have other causes, many treatable, and should be checked. Stopped periods before 40 may mean premature ovarian insufficiency.