7 Surprising things your first period can tell you about your health

3. Preeclampsia

This condition is marked by high blood pressure and protein in the urine during pregnancy. It then becomes a risk factor for stroke afterward. If your first period arrived before age 12, your odds of developing this life threatening condition while pregnant is about 28 percent greater than if menstruation started at age 13 or later, according to a study in the Journal of Clinical & Diagnostic Research.