Frequent Periods in Teenagers

Teen girls don't always have regular periods, particularly when they first start menstruating. Over time, however, most girls experience regular periods that occur, on average, every 21 to 45 days. If your daughter is bleeding more often than that, or more often than what's become normal for her, you should make an appointment with her doctor to discover the cause. In many cases, the cause isn't anything more than her body getting used to having a period, but in some cases, there is an underlying medical reason why she bleeds more often than she should.

Frequent periods can be caused by a medical problem. (Image: Bartosz Ostrowski/Hemera/Getty Images)

Normal Periods

According to KidsHealth, most girls get their first period between the ages of 10 and 15, but the number of days between periods, as well as the number of days your daughter bleeds, can vary much more significantly. While many doctors refer to the average 28-day cycle, that isn't always the magic number for teen girls. The first day of your daughter's cycle is the first day of her period, but the number of days until the first day of her next period can vary from month to month. If she bleeds more often than every 21 days, or more than what's she's noticed as being normal for her, medical attention is necessary.

Puberty and Frequent Periods

In many cases, the reason your daughter might be bleeding more frequently is because her body is getting used to the whole process of having a period. During the first two years following her first period, your daughter's body is adjusting to building up her uterine lining, releasing and egg and then shedding that uterine lining. While her hormones and brain chemicals responsible for reproduction adjust to their new roles, she might have irregular periods including periods that come every two or three weeks instead of following a regular monthly cycle, according to KidsHealth. A 21-day cycle is normal for many young girls and women, and that might be what's regular for her, too.

Medical Causes

In some cases, there's an underlying medical issue that's causing your daughter to bleed more frequently than she should. Fibroids, which are noncancerous growths on the uterus, can cause irregular and frequent bleeding. Endometriosis, which is uterine tissue that has moved to the fallopian tubes or ovaries instead of being expelled during a period, can also cause more frequent bleeding, according to the Family Doctor website. A thyroid problem might also cause irregular or more frequent bleeding. Any of these conditions must be diagnosed by a doctor and immediate treatment can prevent further complications.

Additional Considerations

If your teen daughter is sexually active, more frequent bleeding might be due to a miscarriage. If your daughter suspects that's the cause, seek medical attention to be sure her body is healing. Excess stress or pressure due to exams at school or a big game coming up can also cause your daughter to bleed more frequently. That's because the stress hormones impact how the brain excretes other hormones that play a role in the menstruation process, KidsHealth reports. If your daughter bleeds twice in one month, she might think she's bleeding more frequently than normal. However, if she has a short cycle, such as 21 or 24 days, one period might come at the beginning of the month so the next would start at the end of that same month. That would be considered normal and shouldn't be a cause of concern, according to Kate Kelly, author of "The Teen Health Book."