Missed Period: Causes and What to Do

When is a period late or missed?

A typical cycle lasts 21 to 35 days in adults and up to 45 days in teenagers in the first few years. Cycles naturally vary by a few days from month to month. A period is usually considered late after 5 to 7 days past the expected date, and missed when about 6 weeks have passed since the start of the last one.

Doctors use the term amenorrhea for absent periods:

• Primary amenorrhea: no periods by age 15.
• Secondary amenorrhea: periods stop for 3 months in someone with regular cycles, or 6 months with irregular cycles.

See amenorrhea for the condition in depth.

Could I be pregnant?

If you have had sex since your last period, take a home pregnancy test. Modern tests detect the pregnancy hormone hCG from around the first day of a missed period, and they are most reliable 1 week after the missed period, using first-morning urine. If the test is negative but your period still has not come, repeat it in 3 to 7 days.

Early pregnancy signs include breast tenderness, nausea, tiredness and needing to urinate more. Some people have light spotting around the time of the expected period (implantation bleeding).

Causes of a missed period when not pregnant

Lifestyle and stress

• Stress: emotional stress, illness, exams, grief or travel can suppress signals from the hypothalamus in the brain, delaying ovulation and the period.
• Weight loss or low body weight: low energy availability from dieting, eating disorders or illness stops ovulation (hypothalamic amenorrhea).
• Intense exercise: common in runners, dancers and gymnasts, especially combined with low calorie intake.
• Weight gain and obesity: can disrupt ovulation.
• Shift work and jet lag.

Hormonal conditions

Life stages

• Puberty: cycles are often irregular for the first 2 to 3 years.
• Breastfeeding: prolactin suppresses ovulation; periods may not return for months.
• Perimenopause: from the 40s, cycles become irregular and periods are skipped before stopping. Menopause is confirmed after 12 months without a period.

Contraception and medicines

• Hormonal birth control: pills (especially continuous or progestin-only), the hormonal IUD, the implant and the injection often make periods light or absent. This is safe.
• After stopping birth control: it can take a few months for cycles to return, and longer after the injection.
• Other medicines: antipsychotics, some antidepressants, chemotherapy and steroids.

Less common causes

• Asherman syndrome: scarring inside the uterus after a D&C or infection.
• Pituitary tumors and other hypothalamic or pituitary problems.
• Chronic illness: celiac disease, poorly controlled diabetes, kidney disease.

How doctors find the cause

A doctor will ask about your usual cycle, sexual activity and contraception, recent stress, weight changes, exercise, eating habits, medicines, hot flashes, hair growth, acne and nipple discharge. They examine your body mass index, skin, hair and thyroid, and sometimes perform a pelvic exam.

Tests usually include:

• Pregnancy test, even if you think pregnancy is unlikely.
• Blood tests: thyroid-stimulating hormone (TSH), prolactin, FSH and LH, estradiol, and testosterone if PCOS is suspected.
• Pelvic ultrasound: to look at the ovaries and uterine lining.
• Progestin challenge: a short course of progestin; bleeding afterward shows the body is making estrogen.
• MRI of the pituitary if prolactin is high or there are headaches or vision changes.

What you can do

• Track your cycles with an app or calendar so you can see patterns.
• Eat enough to fuel your activity level, especially if you exercise hard.
• Manage stress with sleep, regular routines and support.
• If you have PCOS or excess weight, losing 5 to 10% of body weight often restores ovulation.

Treatment

Treatment depends on the cause:

• Hypothalamic amenorrhea: increasing calorie intake, reducing exercise intensity and managing stress; support for eating disorders.
• PCOS: combined hormonal contraceptives or cyclical progestin to protect the uterine lining, lifestyle changes, and medicines for insulin resistance or fertility.
• Thyroid disease: thyroid hormone replacement or anti-thyroid treatment.
• High prolactin: medicines that lower prolactin, such as cabergoline.
• Primary ovarian insufficiency: hormone therapy until the usual age of menopause to protect bones and heart.

Long-term absence of periods matters for health. Low estrogen weakens bones. In PCOS, long gaps without periods let the uterine lining thicken, which raises the risk of endometrial hyperplasia and cancer. Treatment prevents both problems.

Frequently asked questions

Why is my period late if I'm not pregnant?

Common reasons include stress, illness, weight loss or gain, intense exercise, travel, breastfeeding, hormonal contraception, polycystic ovary syndrome, thyroid problems and perimenopause. A single late period is usually harmless. See a doctor if you miss 3 in a row.

How late can a period be before I should worry?

A period up to 7 days late is common. If it is more than a week late, take a pregnancy test. If the test is negative and you go 90 days without a period, or you have pain, heavy bleeding or other symptoms, see a doctor.

Can stress cause a missed period?

Yes. Stress affects the hypothalamus, the part of the brain that controls the hormones triggering ovulation. Significant stress can delay ovulation, making the period late, or stop periods for a few months. They usually return once the stress eases.

Can a pregnancy test be negative if I'm pregnant?

Yes, if you test too early, use diluted urine, or ovulated later than usual. Repeat the test in 3 to 7 days with first-morning urine. If your period still has not come and the test is negative, see a doctor for a blood test.

Is it normal to skip periods in your 40s?

Yes. In perimenopause, usually from the mid-40s, cycles become irregular and periods are often skipped. Menopause is diagnosed after 12 months without a period. A pregnancy test is still worth doing, as pregnancy remains possible until menopause.