Ovulation pain. Pelvic pain related to ovulation, which usually occurs at the midway point between menstrual cycles. The pain is due to some problem with ovulation, such as a large cyst. The act of sex during this time can cause the cyst to rupture which can be painful. Mittelschmerz (german for "middle pain") can occur without sex so sex is not actually part of the definition of mittelschmerz.