The age of a girl's first menstrual cycle, called menarche, can vary a year or two from the average age of 12 or 13. Menstruation beginning at younger ages might signal an underlying medical condition, or it might have no specific cause. Because menarche at too young an age might lead to complications in adulthood, treatment is recommended.
Definition
In the United States, girls typically begin menstruating at 12 or 13 years old, according to the women's health website Imaginis. Periods beginning as early as 10 or as late as 16 are considered in the normal range. Early onset menstruation begins before a girl is 10. Menarche is not the first sign of puberty and typically occurs two years after puberty begins. Puberty normally begins in girls between 7 and 8, says The Nemours Foundation. Signs of early puberty in girls younger than 7, called precocious puberty, include growth of underarm or pubic hair, breast development, acne, moodiness or irritability, body odor or rapid growth.
Causes
Early onset menstruation, which follows precocious puberty, begins with the hypothalamus, explains The Nemours Foundation. The hypothalamus stimulates the pituitary gland to produce hormones, which in turn trigger the ovaries to produce estrogen. The surge in hormones might be caused by an underlying condition, such as a tumor, head injury or problem with the ovaries or thyroid gland. Precocious puberty might be inherited, although it happens rarely in girls. Most cases have no discernible cause.
Diagnosis
Menarche and other physical changes are obvious signs of early onset puberty, but a physical examination is necessary for a girl exhibiting early sexual development, advises The Nemours Foundation. Blood or urine tests confirm the presence of excess hormones. Imaging tests, such as X-rays or magnetic resonance imaging scans, rule out tumors or other physical defects.
Treatment
Treatment for precocious puberty aims to halt or slow the progression of puberty, according to The Nemours Foundation. Underlying medical conditions, if present, are treated directly. If precocious puberty has no underlying medical cause, synthetic hormones are used to block production of estrogen. Effects are usually seen within a year after treatment begins.
Long-Term Risks
Menarche might cause emotional and behaviors difficulties in young girls, says Diana Zuckerman, Ph.D. Zuckerman is executive director of the National Center for Policy Research for Women & Families in Washington, D.C. Emerging sexual feelings might confuse young girls, Zuckerman says, or they might be teased by their classmates. Girls developing physically at young ages are at increased risk for aggressive behavior and depression, and they might withdrawal socially. At the same time, they are more likely to engage in risky behaviors, such as sexual activity or drug or alcohol use, than their peers. Early puberty might stunt growth, according to The Nemours Foundation. Early menarche also might increase a girl's risk of developing breast cancer in adult years, notes Zuckerman.
