Miscarriages are also known as spontaneous abortions. Around 50% of pregnancies result in miscarriage. Many women do not realize they are pregnant when they miscarry. They simply have a period that is a bit late or lasts a little longer than usual. Of women who know they are pregnant, approximately 20% have miscarriages.

Women who have more than one miscarriage in a row are diagnosed as having recurrent abortions. If you have a prior liveborn infant, the risk of recurrent abortion is 20% to 25% after one miscarriage, 25% after two miscarriages, and 30% after three miscarriages. If you have not had a liveborn infant, your risk of miscarriage after three prior pregnancy losses is approximately 40%.

It is debatable whether testing for reproductive problems should be performed after two miscarriages or after three miscarriages. If you are in your 30s and have a history of infertility, your physician may recommend evaluation after two miscarriages. All women should be evaluated after three consecutive miscarriages. The following tests are included in a formal evaluation.

  • Karyotyping of you and your spouse (an analysis of your chromosomes through blood testing)
  • Hysterosalpingography (an X-ray of your uterus and fallopian tubes taken while dye is being injected into your uterus). This test determines if there are any abnormalities of your uterine cavity that may be attributing to the pregnancy losses. Alternatively, your physician may order a pelvic ultrasound.
  • Blood testing. Tests may include endocrinologic and immunologic tests.
  • Endometrial biopsy (a sample of the lining of your uterus). This test helps determine whether you are ovulating regularly and producing enough progesterone. Inadequate progesterone production after ovulation is known as a luteal phase defect and may be associated with early pregnancy losses.
  • Cervical cultures (testing for infectious agents in the cervix). Pelvic infections have been associated with pregnancy.