age range of menarche and
In a regression of adult height on age of menarche, the. coefﬁcient estimate is very close to zero and insigniﬁcant, evident in. the height data in row 2 (cols. 4–6) of table 1. Figure 3 shows the kernel. density estimate of adult height by terciles of menarcheal age, revealing. But it turns out that the specifics of your menarche may say more than you realize. First period age is influenced by a huge amount of factors, including up to 100 genes in your body. The average age of first period in the Western world has been getting lower, from an average of 17 over a century ago to around 13 today. In 5 percent of cases menarche occurs between the ages of 16 and 18. Menstruation which starts before 9 is either precocious puberty or a symptom of endocrine disease. About a hundred years ago middle class American girls had their menarche on average at the age of 15.5 years old. Today, it is about at about 12.5 years. Of the women in our sample, 95.5. percent are currently married, 3.1 percent are unmarried widows, and. 1.4 percent are unmarried divorcees. Summary statistics for the sample are presented in table 1, divided. according to age of marriage and age of menarche. The sample includes ever-married women between 25 and 45 with nonmissing. values for age at marriage and age at menarche who reached menarche between 11 and. 17. resides in a district of Matlab that is part of the treatment region for. Timeframe: The average monthly cycle lasts 28 days and is calculated from the first day of your last period to the first day of the next. However, after menarche, it may take a couple of years before your period develops a regular pattern. Your cycle may range from 21 to 45 days; this is nothing to worry about. African American Girls Get Earlier Periods. This is an interesting factor that hasn't been fully explained: Race does seem to have a genuine impact on your menarche time. The difference isn't great — in the U.S., the average age of menarche is 12.88 for white girls and 12.16 for African American girls. If your menarche came before the age of 12, which is around the national average, you need to get tested for breast cancer frequently. Statistics show that, nastily enough, a pre-12 menarche has been linked to a 20 percent higher likelihood of a breast cancer diagnosis at some point in later life. Womens Health » M » 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. So, the chart below gives the events and their ranges. The average age for periods in the U.S. is 12.16 for black girls and 12.88 for whites. By age 11, 28% of black girls and 13.5% of whites menstruate. By age 12, 62% of blacks, and 35% of whites. A girl's first menstruation is called menarche.
The average age of menarche is 12.88 for white girls and 12.16 for African American girls.