One-sided, lower belly pain linked to ovulation.

German for "middle pain," mittelschmerz happens about 14 days before the next menstrual period. It can happen when the ovary lets go of its egg. Some people have it every menstrual cycle. Others have it only sometimes.

Symptoms can include dull, cramplike, or sharp and sudden pain. Mittelschmerz usually lasts a few minutes to a few hours. But it may go on for as long as a day or two.

Pain relievers can ease discomfort. For greater discomfort, birth control pills also can help by stopping ovulation.