How much a girl has to weigh to have her first period?

Answer 1

It's not about how much you weigh. Usually girls will start having periods between the ages of 11 and 15, though it can be as early as 9 or late as 19. However, if a girl's BMI (body mass index) is very low, this may mean her periods do not start until later than they would naturally. Likewise if a girl has already had periods, then becomes very underweight her periods may stop. There is NO weight you need to be to start periods - everybody has different heights and body builds so it doesn't work like that. Unless you think you may be very underweight (in which case you should see a doctor about building up your weight) how big you are should NOT make a difference to when you start. Ask close female relatives (definately your mother, and grandmother if you feel you can) because genetics has a lot to do with when you start!