Mittelschmerz pain usually lasts a few minutes to a few hours, but it may continue for as long as a day or two. Pain from mittelschmerz may be:

• On one side of your lower abdomen
• Dull and cramp-like
• Sharp and sudden
• Accompanied by mild vaginal bleeding or discharge
• Rarely, severe

Mittelschmerz pain occurs on the side of the ovary that's releasing an egg (ovulating). The pain may switch sides every other month, or you may feel pain on the same side for several months.

Keep track of your menstrual cycle for several months and note when you feel lower abdominal pain. If it occurs midcycle and goes away without treatment, it's most likely mittelschmerz.

Mittelschmerz occurs during ovulation, when the follicle ruptures and releases its egg. Some woman have mittelschmerz every month; others have it only occasionally.

The exact cause of mittelschmerz is unknown, but possible reasons for the pain include these:

• Just before an egg is released with ovulation, follicle growth stretches the surface of your ovary, causing pain.
• Blood or fluid released from the ruptured follicle irritates the lining of your abdomen (peritoneum), leading to pain.

Pain at any other point in your menstrual cycle isn't mittelschmerz. It may be normal menstrual cramping (dysmenorrhea) if it occurs during your period, or it may be from other abdominal or pelvic problems.