Learn more about the causes of missed and irregular periods.

If you’re wondering, ‘why did I miss my period?’ your first thought might be pregnancy. But an irregular or missed period can also be your body telling you something about your health.

If you didn’t have sex or pregnancy tests come back negative, consider other common reasons for missed periods. What is your body telling you?

Changes to your menstrual cycle are often due to hormone changes. Because of this, irregular periods can be due to your hormones changing. For example, when you’re a pre-teen, in your early teens, or getting closer to menopause.

But hormone changes and missed periods could indicate a health problem at other times. Your menstrual hormones relate to other processes in your body in complex ways. When these hormones are out of balance, it could be due to sleep, mood, metabolism, or heart health issues.

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Why Did I Miss My Period If I’m Not Pregnant: 8 Common Reasons

A typical cycle is 24 to 39 days, and your cycle should last about the same number of days each month. A cycle starts on the first day of your period and ends the day before your next period.

Below are eight common reasons your cycle may last seven or more days longer than usual when you aren’t pregnant.

Eating disorders, extreme weight loss, or extreme exercise

People without enough body fat may have late or missed periods. This includes:

  • People with eating disorders.
  • People with very restrictive diets.
  • People with extreme exercise regimes, for example, elite athletes.

Too little body fat and intense exercise can stop the body from producing enough estrogen and progesterone. These two hormones regulate the menstrual cycle.

Over prolonged periods, too little estrogen can lead to thin, brittle bones and heart problems. You can talk to your doctor about adjusting your diet or exercise regime so that it doesn’t affect your menstrual cycle. Your doctor can also refer you to treatment programs if you have an eating disorder.

Polycystic ovary syndrome (PCOS)

Polycystic ovary syndrome (PCOS) is a common reason for missed periods. People with PCOS have higher levels of testosterone and other hormones called androgens.

This causes irregular periods and symptoms, including excess body and face hair, acne, weight gain, and thinning hair on the head. These hormone changes also mean that their ovaries don’t release eggs as normal. Instead, the ovaries form cysts or fluid-filled sacs.

People with PCOS also often have high insulin levels. Insulin is the hormone that helps your body use sugar. People with high insulin are at risk of developing diabetes.

People with PCOS have it in their teens but may not recognize the symptoms or get diagnosed until their 20s or 30s. PCOS is often linked to excess weight, so weight loss can help control it. Your doctor may also give you birth control or other treatments to regulate your hormones. It’s important to talk with your doctor if you think you may have PCOS because it can be associated with an increased risk of cancer of the lining of the uterus.

Other health issues

Many health issues other than PCOS can also cause a late period. They include chronic health issues like:

  • Thyroid disease
  • Diabetes
  • Celiac disease
  • Cushing’s syndrome

Blood testing can show signs of health issues affecting your period. To decide which tests to order, your doctor will ask you about other symptoms. Your doctor may also ask you about health problems that run in your family.

Your doctor may also perform a physical exam. This can include checking your weight and blood pressure and looking at your skin.


Some medicines can delay your period. These include hormone therapy, blood-thinning medicines, and drugs to treat cancer.

Ask your doctor if any of your medicines could affect your menstrual cycle. Depending on why you’re taking the medicine, the benefits may outweigh its effect on your cycle. Or, your doctor may suggest another medicine or a lower dose.


Fat cells play a role in the production of estrogen. People with high body fat levels can produce too much estrogen.

This can lead to an imbalance between estrogen and progesterone levels and irregular periods. People who are obese may have longer cycles and heavier periods. Or they may even stop having their period.

People who are overweight or obese are also at a higher risk for PCOS. Talk to your doctor about weight loss help if obesity is contributing to your irregular periods.


Stress is one of the most common reasons for a missed period. While stress happens occasionally, too much stress for too long can harm your health. High-stress levels increase your risk for high blood pressure, diabetes, and cancer.

When you’re stressed, your body releases more of the hormone cortisol. This can trigger a higher or lower level of other hormones, including the ones that regulate your cycle. That’s why stress can lead to late, or even early, periods.

Ways to reduce stress include:

  • Lowering your workload.
  • Exercising.
  • Meditating,
  • Talking to supportive friends.
  • Getting more sleep.

You can try different healthy coping methods to see what works best.


If you’re over 40, perimenopause could be the reason for your missed period. This transition period occurs before you stop releasing eggs and menstruating, called menopause. Perimenopause can last seven or more years before menopause, according to the National Institutes of Health.

During perimenopause, estrogen and progesterone levels can go up and down differently. This can shorten or lengthen your cycles. Periods can get heavier or lighter than usual.

While perimenopause is natural, it can cause many symptoms. These include:

  • Sleep troubles.
  • Mood changes.
  • Hot flashes.
  • Vaginal dryness.

If you find these symptoms difficult, your doctor can suggest medicines or lifestyle changes that may help.

Menopause is official once after at least 12 months of missed periods. It typically occurs between 45 and 58. ‘Early’ or ‘premature’ menopause happens before 45 and may be due to a health problem, smoking, or genetics.

Young age

Irregular and missed periods are normal for teenagers. For instance, teens may have a cycle of 25 days and then a cycle of 32 days.

After the first few years, the menstrual cycle should become more consistent in timing and flow. If you have any questions about a normal period, your doctor can help.

Centers for Disease Control and Prevention. PCOS (polycystic ovarian syndrome) and diabetes. Link

Hallie Levine. 11 reasons for a missed or late period. What To Expect. Link

Maria Carter. 7 reasons for a late period that aren't pregnancy. Parents. Link

Dr. Bridget Kuehn. Rising heart risks for young women linked to low estrogen. Circulation. Link

National Institute on Aging. What is menopause? Link

National Institute of Health. About polycystic ovary syndrome. Link

Office on Women's Health. Period problems. Link

Emma-Louise Pritchard and Kirsti Buick. Amenorrhea: What Might Be Causing Your Missing Periods. Women's Health. Link

About UPMC Magee-Womens

Built upon our flagship, UPMC Magee-Womens Hospital in Pittsburgh, and its century-plus history of providing high-quality medical care for people at all stages of life, UPMC Magee-Womens is nationally renowned for its outstanding care for women and their families.

Our Magee-Womens network – from women’s imaging centers and specialty care to outpatient and hospital-based services – provides care throughout Pennsylvania, so the help you need is always close to home. More than 25,000 babies are born at our network hospitals each year, with 10,000 of those babies born at UPMC Magee in Pittsburgh, home to one of the largest NICUs in the country. The Department of Health and Human Services recognizes Magee in Pittsburgh as a National Center of Excellence in Women’s Health; U.S. News & World Report ranks Magee nationally in gynecology. The Magee-Womens Research Institute was the first and is the largest research institute in the U.S. devoted exclusively to women’s health and reproductive biology, with locations in Pittsburgh and Erie.