While pregnancy is the most common reason for missing a period, there are other possible causes. These include:
- Intense exercise or significant weight loss. Women who exercise intensely or have sudden changes in body weight can experience low levels of the hormone estrogen, which can result in missed periods.
- Obesity: Just as losing too much weight can have an impact on a woman’s menstrual cycle, so can excessive weight gain. If you believe weight gain may be the cause of your missed period, talk to your healthcare provider to create a diet plan that can help you achieve your weight loss goals and normalize your monthly cycle.
- Stress. The hypothalamus region of the brain both controls the release of hormones and is extremely sensitive to stress. When you experience extreme stress, it can disrupt hormone production and interfere with your menstrual cycle.
- Polycystic Ovarian Syndrome (POS). This condition is seen in at least 5%–10% of women and often results in irregular periods, as well as symptoms like excess hair growth and infertility.
- Low thyroid hormone. A rare cause of missed periods is low levels of the thyroid hormone. This condition gradually reverses with thyroid hormone supplementation. Low thyroid hormone can occur for many reasons, including disorders of the thyroid gland such as Hashimoto’s disease.
- Medications. Some medications can affect the menstrual cycle. These include drugs like tamoxifen, antidepressants, corticosteroids, antipsychotics, and certain hormonal contraceptives. Once the medication is discontinued, the menstrual cycle should resume its normal cyclical activity.
- Radiation and cancer treatment. Women who undergo radiation therapy or take medication for cancer can develop ovarian failure, which can result in the loss of periods or an irregular cycle.