BIOLOGY | MEDICAL | HEALTH on Instagram: "Menstrual cramps happen when your uterus contracts to shed its inner lining. During your period, the hormone prostaglandins increases—this triggers strong contractions that help push out the menstrual blood. But when prostaglandin levels are high, the uterus squeezes too hard, reducing blood flow and oxygen to the muscles, which creates sharp, throbbing pain in the lower belly, back, and thighs. These contractions can also cause nausea, fatigue, and head