age of menarche generally
If noticeable breast development doesn’t begin by age 16, consult a physician. The emergence of body hair usually begins in the pubic area about the same time as breast development, usually starting at age 10 or 11 but sometimes not occurring until age 13 or 14. Underarm and leg hair appears a year to two later. In general the color, thickness, and pattern of body hair is quite variable. Menarche. The average age of menarche, or first menstruation, in the United States is 12.88 years for Caucasian girls and 12.16 years for African American girls. A popular misconception is that menarche marks the beginning of puberty; in reality, menarche occurs later in puberty. Records suggest that there was a secular decline in the average age at menarche in developed countries across the 19th and 20th Centuries until the 1950s, with an average age at menarche of 15-17 years reported in the mid-19th Century. While a mother's age at menarche appears to be a better predictor of the daughter's age at menarche than other external factors, research supports the role of family structure in determining pubertal timing. Changes in Girls. The onset of sexual maturation in girls usually begins about two years earlier than it does in boys. The process of puberty can take anywhere from two to six years and can begin anytime between ages 8 and 14. (If a girl begins developing before age 8, puberty is considered to be premature, and a doctor should be consulted.). An increase in height usually begins at age 10 to 11 and continues to age 15 to 16. It has been suggested that pubertal timing may then have plateaued in the 1950s, although further small declines have subsequently been reported. While recent estimates of the median age of menarche vary between 13 to 16 years, recent data suggest that the age of 15 years represents the 95-98th percentile for menarche. Several studies have examined birth size and infant growth in relation to age at menarche (Table 1). In a study investigating Filipino girls, long and thin infants had earlier menarche and this effect was strongest for girls with higher growth rates from 0-6 months. In examining early life predictors of age at menarche, three major themes have emerged, namely the effects of body size, social circumstances and exposure to unfavorable psychological circumstances. *Menstrual cycles are the most irregular during the first 2 years after menarche and during the 3 years before menopause. At both times, anovulation (absent ovulation) is most common. Andrenarche (8 y.o.) Gonadarche (8 y.o.) Thelarche-Breast bud (10-11 y.o.) Pubarche-Onset pubic hair (11-12 y.o.) Maximal growth (11-12y.o.) Menarche (11.5-12.8 y.o.) Adult pubic hair-13.7 y.o. Adult breast-14.6 y.o.
12.88 years for Caucasian girls and 12.16 years for African American girls.