There are many reasons why a woman’s period might come early, including severe weight loss or gain, certain medications, metabolic syndromes, endocrine disorders, stress or the onset of perimenopause. Experts consulted by Health magazine recommend seeing a gynecologist within three months of a sudden period change to rule out underlying health problems that could require immediate treatment.
An early period, or any type of irregular period, can be a sign of perimenopause, a time of five or more years before menopause begins and a woman’s childbearing years start to end. If a woman normally has her period at regular intervals, say every 28 days, and she starts having it on an irregular basis, say on day 21, then 35, then 30, this could be the beginning of perimenopause. A woman with perimenopause may also experience sleep trouble, mood changes, occasional hot flashes and anxiety, according to Health magazine.
Many other things can also disrupt a woman’s hormone levels and lead to irregular or early periods. Some of these culprits include severe changes in weight, stress and medications that affect the central nervous system, like antidepressants. Thyroid disease and other endocrine disorders that affect hormones can also make a woman’s period come early or irregularly. Polycystic ovary syndrome/disease and metabolic syndrome, both of which can lead to obesity, also sometimes shorten, lengthen or otherwise change a woman's cycle, notes Health magazine.