Explaining Biology on Instagram: "On the first day of your period, your body goes through an intense process. The uterus begins to contract to shed its inner lining — the endometrium — which had thickened to support a possible pregnancy. These contractions, triggered by hormone-like substances called prostaglandins, cause cramps and pain in the lower abdomen and back. Before and during this time, some women notice white discharge. This discharge, known as leukorrhea, is mostly composed of cervic