Can Weight Loss Lead to an Irregular Period?

From time to time a woman will experience an irregular menstrual cycle. Irregular menstrual periods can occur when there is a hormonal imbalance, as a consequence of stress, weight gain or weight loss. Losing a considerable amount of weight can cause the period to become scanty, heavy, shorter or longer than normal. It may also cause a woman to suffer from an imbalance in hormones, which can directly cause the irregularity.


A normal menstrual cycle lasts anywhere from 25 to 36 days with an average of 28 days. On a regular menstrual cycle, a woman bleeds for three to seven days and the amount of blood lost is about 0.5 to 2.5 oz. This blood flow can be light, medium or heavy and may contain a few blood clots. The menstrual cycle is orchestrated by the luteinizing and follicle-stimulating hormones, secreted from the pituitary gland. These hormones send signals to the reproductive system, which causes the production and release of estrogen and progesterone. Losing a considerable amount of weight due to dieting or an eating disorder may cause fluctuations in the thyroid gland, which results in reduced levels of these reproductive hormones. This causes a condition known as secondary amenorrhea, or an absence of menstruation.


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The main symptom of secondary amenorrhea is the absence of menstrual periods for three or more months, as stated by the Mayo Clinic. Some women may also experience milky nipple discharge, headache, visual disturbances, facial hair growth and hair growth on the body.


In addition to the weight loss and determining or examining the cause, your doctor will perform several tests to identify the root cause of your irregular menstrual cycles. To do this, he may first perform a pregnancy test, followed up by a pelvic examination. This exam will enable your physician to check for any enlargements or growths within your reproductive hormones. Next, he may want to perform a physical exam and a series of blood tests, which will check various hormones for irregular levels. If needed, you may have to take a progestogen medication for up to 10 days, to reveal whether the absent menstrual period is triggered by a lack of estrogen.


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Treatment for amenorrhea in regards to weight loss may consist of a mixture of hormone therapy in the form of birth control pills and medications to correct the thyroid or pituitary gland. In addition to medical treatments, your doctor may suggest a modification in lifestyle activities in order to increase your weight and physical activity levels.