What tests do I need if I'm having recurrent miscarriages?

A miscarriage is the loss of a pregnancy before 20 weeks.

Miscarriage happens in 10% to 20% of all pregnancies. This means the risk of having two miscarriages in a row, just by chance alone, is 2% to 3%.

Doctors interpret this number differently when they define the condition known as "recurrent pregnancy loss." Some diagnose it after two miscarriages, others after three.

There are many potential causes of recurrent pregnancy loss. And there are many tests to evaluate the condition. It is reasonable to do some less invasive testing after two losses and a complete evaluation after three.

No cause of recurrent miscarriage is found in about half of affected couples. Recognized causes include:

• abnormalities in the shape of the uterus
• genetic factors
• hormone deficiencies
• infections
• immune factors

An initial examination to investigate this condition might include:

• a careful review of all prior pregnancies
• a complete pelvic examination
• a variety of blood tests

Additional testing is based on these first results.

After two miscarriages in a row, the chance for a third is about 25%. The risk in a particular woman is influenced by several factors. These include:

• the age of the mother (the risk goes up with age)
• the cause of miscarriage
• the time in the pregnancy when the loss occurs (the risk goes up if a miscarriage happens later in pregnancy)

However, it is important to know that the outlook for a successful pregnancy is good for most couples with recurrent pregnancy loss. One study showed that more than 70% of couples will have a successful pregnancy even if no specific diagnosis is made and no treatment is given.

Of all pregnancies, 15-20% end in miscarriage; 75% of these in the first 12 weeks of pregnancy. Infertility is defined as 2 or more consecutive miscarriages. If you have experienced multiple miscarriages, you may need one or more of the following tests:

• Hormonal Factors Tests. Ask to have a prolactin, thyroid and progesterone level taken. If they are abnormal and treatment is given, make sure that you are re-tested to check your levels.
• Structural Factors Tests. A hysterosalpingogram is done to evaluate the shape and size of your uterus and to rule out possible scarring, polyps, fibroids or a septal wall, which could affect implantation. If there is concern about the uterine cavity, a hysteroscopy (examination done in combination with laparoscopy or as an office procedure) can be done. In some women the cervical muscle is too loose, causing pregnancy loss after the first trimester. A special exam is done when a woman is not pregnant to check for an incompetent cervix.
• Adequacy of the Uterine Lining Tests. An endometrial biopsy is done on cycle day 21 or later and will document if your lining is getting thick enough for the fertilized egg to implant. If you have a lag of two or more days in the development of the lining, you will be treated with various hormones (Clomiphene, hCG, Progesterone). It is important to have the biopsy repeated after several cycles to ensure the treatment is helping. If you are on Progesterone, discuss the advantages of the oral, vaginal gel creams or tablets or injection routes with your doctor.
• Tests for Chromosomal Causes. Chromosomal tests are rarely done on tissue from a miscarriage because it is difficult to preserve the tissue for adequate studies. If chromosome testing is needed, you and your partner will have blood tests to make sure there is no translocation of genes (a condition in which the number of genes is the normal 46, but they are joined together abnormally). This condition can result in pregnancy loss.
• Tests for Immunologic Causes. Blood tests to check for immunologic responses that can cause pregnancy loss include antithyroid antibodies (antibodies to thyroglobulin and thyroid peroxidase) the lupus anticoagulant factor and anticardiolipin antibodies. These appear to influence blood clotting mechanisms within the placenta as it develops. There are also blood tests that check for protective blocking factors. These are essential to protect the pregnancy from being rejected by the mother's body.