What is mittelschmerz?

Mittelschmerz is pain a woman might feel on one side of the belly once a month while she is ovulating. The pain is usually mild. It's a sign that she's released an egg from one of her ovaries. A woman is most fertile—and more likely to get pregnant—when she ovulates.

Mittelschmerz can be used to plan when to have sex to try to become pregnant. But using mittelschmerz to time sex to avoid pregnancy usually doesn't work.

What happens when you have mittelschmerz?

When you ovulate, a mature egg is released from one of your ovaries. Two things happen naturally at this time that may cause the pain:

• The small sac (follicle) on the ovary where the egg matures grows rapidly and stretches the surface of your ovary.
• When the follicle squeezes the egg out, the blood or fluid in the follicle may irritate the tissues around it.

What are the symptoms?

• The pain is usually mild, like a sharp cramp on one side of your belly. It may shift from side to side from one menstrual cycle to the next. Or it may stay on the same side for more than one cycle.
• The pain lasts from a few minutes to a few hours. It may last up to 24 to 48 hours.

How is mittelschmerz treated?

• Take an over-the-counter pain medicine, such as acetaminophen (Tylenol), ibuprofen (Advil, Motrin), or naproxen (Aleve) if needed. Read and follow all instructions on the label. Do not take two or more pain medicines at the same time unless the doctor told you to. Many pain medicines have acetaminophen, which is Tylenol. Too much acetaminophen (Tylenol) can be harmful.
• If you are trying to get pregnant, talk with your doctor about which pain medicine is safest in early pregnancy.

When should you call for help?

Call your doctor or nurse advice line now or seek immediate medical care if:

• You have severe vaginal bleeding.
• You have new or worse belly or pelvic pain.

Watch closely for changes in your health, and be sure to contact your doctor or nurse advice line if:

• You have unusual vaginal bleeding.
• You do not get better as expected.