Besides pregnancy, there are a number of possible reasons for a missed period. Pregnancy is by far the most common cause of a missed period, but there are some other medical reasons and lifestyle factors that impact your menstrual cycle. Extreme weight loss, hormonal irregularities, and menopause are among the most common causes if you’re not pregnant.
You may miss a period for one or two months, or you may experience complete amenorrhea, which is a lack of menstruation for three or more months in a row. Here are 10 common reasons your period may be delayed:
Profound stress alters the production of a gonadotrophin-releasing hormone (GnRH), interfering with ovulation and regular menstruation.1
The type of stress that’s severe enough to affect your menstrual period usually isn’t just a matter of having a lot going on at work or school.
If you’re coping with an overwhelming situation or experiencing prolonged anxiety, with more than one missed period, talk to your doctor and get a referral for counseling to help you decide what to do about the issues that are causing you stress. Once your stress is back to a manageable level, it can sometimes take a few months or more for your cycles to become regular again.
Extreme exercise can cause alterations in pituitary hormones and thyroid hormones, resulting in changes in ovulation and menstruation.2 Don’t worry about exercise causing you to miss your cycle if you work out for one or two hours per day. It takes strenuous exercise for hours and hours every day to produces these hormonal changes.
If you are planning on exercising for hours every day, be sure to see a sports medicine doctor who can work with you on maintaining optimal nutrition, recommended stretching, and blood testing as needed, so that your body can support all of the physical demands that you are putting on it.
What Are Some Unexpected Changes to Your Period When You Exercise?
Chronic conditions that can affect your menstrual cycles include thyroid disease, polycystic ovarian syndrome (PCOS), pituitary tumors (which may or may not be cancer), diseases of the adrenal gland, ovarian cysts, liver dysfunction, and diabetes.3
When any of these illnesses interfere with your cycle, it may not return to normal until the condition is treated. Congenital chromosomal conditions such as Turner syndrome and androgen insensitivity syndrome typically cause menstrual and fertility problems and are often associated with amenorrhea.
Acute illness, such as pneumonia, a heart attack, kidney failure, or meningitis, can result in rapid weight loss and nutritional deficiency or hormone dysfunction, which can cause you to miss your period during the illness. After the illness is resolved, it might take a few months before your period returns again.
A Change in Your Schedule:
Changing schedules can throw off your body clock.4 If you frequently change work shifts, going from days to nights, and particularly if your schedule is erratic, your period can be fairly unpredictable.
Generally, changes in schedule shouldn’t cause you to completely miss your period but can cause it to start earlier or later than expected. Your cycle can also change by a few days if you experience jet lag.
Some medications, such as antidepressants, antipsychotics, thyroid medications, anticonvulsants, and some chemotherapy medications, may cause your period to be absent or delayed.5
Hormonal contraceptives like Depo-Provera, progesterone-only MiniPill, Mirena IUD, and Nexplanon can also influence your cycle.
Each type of contraceptive has its own list of anticipated effects on your menstrual cycle, and some are associated with heavy periods, some with light periods, and some with amenorrhea.
Being overweight, underweight, or experiencing drastic changes in weight all impact your cycle.6 Obesity influences estrogen and progesterone and may even result in decreased fertility. Very high body mass index (BMI) is associated with missed periods, and weight loss can help regulate the menstrual cycle for women who are obese.
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 with anorexia (very low food intake) or who burn far more calories with exercise than what they consume by eating may experience amenorrhea. Typically, weight gain will help your periods to return.
Rapid weight changes, which can include weight gain or weight loss due to illness, medication, or dietary changes, may interfere with hormone production or release, causing you to miss one period or more.