What is the average age when girls get their periods and what are the characteristics when you are about to have them?

Answer

Dear Adeline,

There are several mechanisms of interest here, but unfortunately not all mechanisms are known yet. For example, you need a certain fat percentage to get everything going; skinny girls are less likely to start menstruating.

A (white) girl normally gets the first lines between 10 and 16 years of age and only follows after breast development, pubic hair and your growth spurt. If there is no breast development yet, you will normally not menstruate. Your ovaries have to start producing estrogens (female hormone), which ensure breast development; you will not menstruate until you have ovulated. On average, this is 13 years, but this can also be later.

At 12 years, 95% of girls have normal breast development, if you do not already have this, further research is indicated.

kind regards,