If you missed a period and you’re pretty sure you’re not pregnant, there could be several reasons for your irregular cycle. Women are more likely to miss a period in the first few years after menstruation starts and again as they near menopause, but it can happen at any age. Knowing when to call a doctor for this common condition can be confusing, so here is some information to help clarify when it’s time to pick up the phone. Common Causes of a Missed Period or Irregular Periods There are many reasons for missing a period other than pregnancy, but you should ask yourself first if there is any chance you could be expecting. A home pregnancy test can be a first step to finding out for sure. Most causes of missing a period or having irregular periods stem from abnormal amounts of the female hormone estrogen, which is required for ovulation and a complete menstrual cycle. Here are some of the more common causes for missed periods in nonpregnant women: Eating disorders like anorexia or bulimia Female athlete triad, a condition involving low caloric intake and low estrogen levels, which leads to low bone density and irregular or no periods Polycystic ovary syndrome, a hormone imbalance with higher-than-normal male hormones High prolactin levels Uncontrolled diabetes Obesity Certain medications including antiseizure and antipsychotic drugs Stress and fatigue Overactive thyroid Primary ovarian insufficiency, a condition with lower-than-normal estrogen levels, which inhibits ovulation Pelvic inflammatory disease, an infection of the female reproductive organs What to Do at Home for a Missed Period If you have missed a period, consider taking an at-home pregnancy test to ensure that you are not pregnant. If you are not already doing this, it’s helpful to keep track of the day your period starts and stops month over month, especially during the first few years of menstruation, after a pregnancy, and as you near menopause, which is typically between the ages of 45 and 55. Keeping a menstrual calendar will help you identify significant changes in your cycle, including the length of each cycle. If you are extremely stressed, fatigued or you have been traveling extensively, try to relax and make sure you are eating well. However, there is no reliable self-treatment for a missed period, so avoid recommendations for home remedies that you read or hear about. Instead, consider whether it’s time to call the doctor. When to See a Doctor for a Missed Period Call your doctor if you haven’t had a period for three or more months, or an at-home pregnancy test comes back positive. Amenorrhea is a complete absence of menstrual periods for a non-pregnant woman prior to menopause. It’s important you get professional medical care to diagnose the underlying problem and avoid complications of a potentially serious condition, such as uncontrolled diabetes. Who to See for a Missed Period Make an appointment with your gynecologist, who can help you address the underlying reason why you missed a period. Your gynecologist will consider your menstrual cycle in the context of any other signs and symptoms to help reach a possible diagnosis. You may need blood tests to measure hormone levels. Your doctor may refer you to another specialist, such as an endocrinologist if necessary. If you don’t have a gynecologist, call your primary care doctor. Missed periods are common, but if it has been a few months or you feel any cause for concern, consult your doctor.