Starting First Menstrual Cycle

Starting your first menstrual cycle is an important part of your transition from a girl to a woman. Menstruation begins during puberty; according to the American College of Obstetricians and Gynecologists, as your body matures, your brain tells your body to start producing the hormones that control your menstrual cycle. Girls usually start their first menstrual cycle around age 11 or 12, although it is normal to start a few years earlier or later.

Pregnancy

• Starting your first menstrual cycle means that you are now able to get pregnant and have a baby. As Planned Parenthood points out, however, it is important to remember that you can actually become pregnant before you get your first period. Every period is preceded by ovulation, the release of an egg from one of your ovaries. In the case of your first period, your body will release an egg before you even know that you've started your menstrual cycle. Since you may start your menstrual cycle anytime during puberty, it's important always to use birth control if you have sex before you start menstruating.

Typical Age

• According to the National Women's Health Information Center, menstruation usually begins around the age of 12, although it is normal for it to begin as early as age 8 or as late as 15. Menstruation typically begins about two years after a girl's breasts start to grow. Although, as the American College of Obstetricians points out, some girls do not menstruate during their teen years; failure to begin menstruating by age 15 may be a sign of an underlying problem.

First Period

• According to the American College of Obstetricians and Gynecologists, in most cases a girl's first period is very light: there may only be a little bit of blood, and bleeding may only last for a short period of time. Some girls experience cramps during their period or notice other symptoms before their period starts, such as mood swings or headaches.

First Few Years

• As TeensHealth from Nemours explains, it is normal to have irregular menstrual cycles during your first year of two of menstruation. Your cycles during this time may be longer than normal, lasting anywhere from 21 to 45 days. It's also not unusual to miss a period entirely. Your periods will probably become more regular as you get older, although some women do continue to have irregular menstrual cycles in adulthood.

When to See Your Doctor

• According to the National Women's Health Information Center, you should see your doctor if you haven't gotten your first period by the age of 15 or if your period hasn't appeared within three years of when your breasts began to grow. You should also see your doctor if your period disappears for more than three months, even if you only recently started menstruating.