That’s a very good question. I can only partly answer because there is a lot that is not yet known. Let’s start with what we do know. The cramps, backache and headache all are caused by a hormone called “Prostaglandin.” The uterus makes more prostaglandins when your own hormone levels, especially estrogen, are higher. It may take several years after your first period to “work up to” those high levels. For women in general, it tends to happen in the springtime, with weight gain, or when physical activity is less.
Your uterus also makes more prostaglandins when there is more pressure inside of your uterus. That happens naturally as your uterus gets bigger and the muscle in its walls gets stronger. After a woman has had a baby the opening of the uterus is less tight and cramps become more mild or disappear.
Finally, there seems to be less prostaglandin made and fewer cramps when progesterone levels are higher. As you grow up your ovaries will begin to release an egg and make progesterone more regularly or in higher doses. That should help your cramps.
In the meantime, for information about what you can do to help with your cramps, read “Painful Periods [1]”.
I hope this is helpful to you. All the best.
