9 Reasons (Other Than Pregnancy) for a Missed Period

Pregnancy is by far the most common cause of a missed period. However, other medical and lifestyle factors can also affect your menstrual cycle and make your period late. If you're not pregnant, then weight changes, hormonal irregularities, and menopause are among the most common causes of a missed period.

With these issues, you may miss a period for one or two months, or you may experience complete amenorrhea—meaning no period for three or more months in a row. A normal menstrual cycle (the day your period starts to the first day of your next period) is about 28 days. However, a normal cycle could be up to 38 days. If your cycle is longer than this, or longer than is usual for you, it's considered late.

This article explores nine common reasons (other than pregnancy) that can cause delays with your period.

Age-Related Changes

Many changes to your period, including missed periods, are related to your age and stage of the life cycle.

Recently Started Periods

Not all age-related changes to your period will occur in older people. It's common for younger people, especially teens who have just started menstruating, to have irregular or missed periods.

It may take a little while for your period to happen every month. Women who have not had a period due to contraceptive use, hormonal therapy, or illness may not resume regular, monthly periods right away.

Primary Ovarian Insufficiency

Primary ovarian insufficiency (POI) happens when the ovaries stop functioning normally before a person reaches the age of 40. It is sometimes called premature ovarian failure.

This can cause irregular periods and fertility problems to begin before the typical age of perimenopause. The cause of POI isn't well understood, but it is believed to be related to the function of the follicles. These are small sacs in the ovaries where eggs mature. In people with POI, there may not be enough working follicles.

Perimenopause

Perimenopause is the period of transition between reproductive age and a non-reproductive age. Your periods may be lighter, heavier, more frequent, or less frequent during this time. In most cases, they'll just be different than what you're used to.

Not all age-related changes to your period will occur in older people, though. It's common for younger people, especially teens who have just started menstruating, to have irregular or missed periods. It may take a little while for your period to happen every month.

Menopause

Menopause occurs as you reach an age when you will no longer ovulate or menstruate. The average age of menopause is 51 years old.

Premature menopause occurs in people younger than 40 and early menopause occurs in people between the ages of 40 and 45 years. Early menopause can occur naturally, or as a result of surgery (like having the uterus removed), chemotherapy for cancer treatment, or other issues.

Stress

Intense stress interrupts the production of gonadotrophin-releasing hormone (GnRH)—a hormone that regulates ovulation and the menstrual cycle.

Missing one period while going through a very stressful situation is not uncommon. People who have significant or prolonged levels of stress may experience an irregular menstrual cycle. A professional counselor or healthcare provider can offer strategies to handle high stress levels, so consider a consultation if you miss three or more periods.

If there is no other medical reason for your missed period, your healthcare provider may suggest counseling to help you cope with your situation. Once your stress is back to a manageable level, it may take a few months or more for your cycles to become regular again.

Polycystic Ovary Syndrome (PCOS)

People with polycystic ovary syndrome (PCOS) have a hormonal imbalance that can cause delayed or irregular periods. If you have PCOS, you will likely have other symptoms besides just an irregular menstrual cycle. Some of these may include:

• Weight gain/trouble losing weight
• Infertility
• Acne
• Hair loss or thinning
• Hair growth on the face or body
  

Weight

Rapid weight changes due to illness, medication, or dietary changes can interfere with hormone production or release. In turn, this may cause you to miss one period or more. But more chronic issues, like obesity and overweight or being underweight due to anorexia, also can lead to missed periods.

Obesity

Obesity influences estrogen and progesterone regulation and is associated with missed periods. It may even lead to issues with fertility. Weight loss can help regulate the menstrual cycle for women who are obese.

Low Body Weight

Being severely underweight interferes with regular menstrual cycles as well. When the body lacks fat and other nutrients, it cannot produce hormones the way it should.

Women who have anorexia (very low caloric intake) or who burn far more calories with exercise than what they consume may experience amenorrhea. Typically, weight gain will help your periods to return.

Chronic Diseases

Chronic conditions that can affect your menstrual cycle include:

• Pituitary tumors (which may or may not be cancer)
• Diseases of the adrenal gland
• Ovarian cysts
• Liver dysfunction
• Diabetes

Certain conditions that are present at birth, such as Turner syndrome and androgen insensitivity, typically cause menstrual and fertility problems. These congenital conditions are often associated with amenorrhea.

Thyroid Disease

People with thyroid disease have too much or too little thyroid hormone. Thyroid hormone has many functions in the body, including menstrual cycle regulation. When you don't have the right amount of thyroid hormone, you might have periods that are irregular. Some people with thyroid disease may miss their periods altogether, often for a few months or more.

Acute Illness

Acute illness, such as pneumonia, a heart attack, kidney failure, or meningitis, can result in rapid weight loss, nutritional deficiency, or hormone dysfunction. These conditions can also result in a missed period.

Extreme Exercise

Extreme exercise can cause changes in pituitary hormones and thyroid hormones, which can impact ovulation and menstruation. Working out for one or two hours per day shouldn't affect your menstrual cycle. It usually takes hours upon hours of demanding exercise every day for these hormonal changes to occur.

If you are planning on exercising that much, you may want to consult with a sports medicine healthcare provider. Their job is to help your body support all of the physical demands that you are putting on it. This may include:

• Optimizing your diet with nutritious foods that boost your energy
• Teaching you stretching techniques to reduce physical stress
• Performing blood tests to check for iron or vitamin deficiencies, hormonal imbalances, dehydration, and more

Medication

Some medications, such as antidepressants, antipsychotics, thyroid medications, anticonvulsants, and some chemotherapy medications, may cause your period to be absent or delayed.

Breastfeeding

You may have light periods, infrequent periods, or amenorrhea when breastfeeding, particularly if breastfeeding provides your baby with all or almost all of their calories.

Many women believe that breastfeeding is a form of birth control. While it can reduce your chances of getting pregnant, it is not 100% effective. Even if you don't have periods when you are breastfeeding, you can get pregnant. If you are not ready for another child, you should use a backup contraceptive.

When to Call Your Healthcare Provider

Missing a period every once in a while is usually not cause for concern. How much of a delay is normal for your period? It depends. On average, a menstrual cycle lasts 28 days, but 38 days could also be within the range of normal. And your cycle will change throughout your life, so at some time, you're likely to experience a late period when you're not pregnant.

That said, you should contact your healthcare provider if you miss more than one period, or if your missed period is accompanied by new or unusual symptoms.

Seek medical attention right away if you also experience any of the following:

• New or worsening headaches
• Vision changes
• Nausea or vomiting
• Fevers
• Hair loss
• Breast discharge or milk production
• Excess hair growth

Summary

There are many reasons for late periods. These are often related to changes in the body that cause a hormonal imbalance, such as stress, certain illnesses, or medication. While most are not cause for alarm, you do need an evaluation and treatment if you have completely missed more than one period.