Most women in the middle of their child-bearing years have periods that occur on a fairly regular basis, usually about every 28 days. But life events, including stressful situations, can sometimes disrupt this regularity and cause your periods to occur earlier than expected. Your method of birth control and certain gynecologic or medical conditions may also cause an early period. Contact your doctor if you have early periods on a frequent basis or if your bleeding is excessive or accompanied by significant pain.
Age and Life Events
Periods are produced by the action of female hormones on the lining of the uterus. When menstruation first starts during the adolescent years, these hormone systems are not yet fully mature and it may take 6 or more years for periods to become regular. Before periods become regular, early periods are common. Periods become irregular again when women enter the perimenopausal years, which typically occurs in their 40’s. Early periods are fairly common at this stage of life as well. Life events can also affect hormone levels and result in periods that occur earlier than expected. High levels of exercise, large changes in weight, any major medical illness, and even mental stress may cause an early period.