Recurrent Miscarriages

Miscarriage is one of the most devastating experiences that can happen to a woman. Having one miscarriage is sadly, not that uncommon. Approximately two out of every ten pregnancies will result in miscarriage. After having one miscarriage most women go on to have a healthy pregnancy. Still there are a few women that will continue to have two, three or more miscarriages. Women are considered to have recurrent miscarriages when they have two or three miscarriages in a row. According to the American Society for Reproductive Medicine, only about one percent of women will have three consecutive miscarriages or more. Many doctors will not perform any tests until after a woman has had three consecutive miscarriages. Even with testing, doctors may not be able to determine the cause of recurrent miscarriage.

Possible recurrent miscarriage causes generally fall into the following categories:

• Anatomical
• Blood clotting/immunological
• Hormonal
• Genetic
• Unknown

Anatomical Causes of Miscarriages:

Sometimes, something is physically different about a woman’s uterus in a way that reduces her chances of a successful pregnancy. This might mean her uterine shape is abnormal or her cervix is weakened in a way that reduces her odds of a successful pregnancy. Anatomical factors that may cause recurrent miscarriages include:

• Uterine septum (or other congenital problems)
• Cervical insufficiency
• Fibroids (controversial)
• Uterine scarring

Blood Clotting/Immunological:

The exact mechanisms by which blood clotting disorders cause miscarriages are not yet well understood, but the primary condition in this category that doctors test for is called antiphospholipid syndrome. Hereditary thrombophilias, such as Factor V Leiden, have been implicated in late pregnancy losses.

You may find mention of other immune system-based miscarriage causes around the Internet, such as elevated Natural Killer cells or HLA incompatibility, but these factors are not widely accepted as miscarriage causes by the mainstream medical community.

Hormonal:

The idea that hormonal problems cause recurrent miscarriages is controversial. Progesterone deficiency, particularly, is hotly debated, and asking different doctors about the issue may result in different answers. Low progesterone should be considered inconclusive as a recurrent miscarriage cause. These conditions have been tied to recurrent miscarriages also, but they require more research.

• Elevated prolactin
• Insulin resistance
• Thyroid disorders

Genetic:

Sometimes, recurrent miscarriages do have a chromosomal cause. Women (and men) older than 35 have a greater tendency to produce eggs or sperm with chromosomal abnormalities.

In other cases, one or both partners may have a balanced translocation or other silent chromosomal abnormality that gives the couple a statistically increased odds of miscarriage in each pregnancy.

Unknown:

Medical practitioners can find a cause for a couple’s recurrent miscarriages only about half the time. The other half of the time, the cause is unknown. If you end up falling into this category, take heart. Studies have found that couples with recurrent miscarriage due to unknown causes have a 70% chance of eventually having a normal pregnancy.

Testing:

What follows is a list of the most common tests that doctors use for women with recurrent miscarriages. Note that the field of recurrent miscarriage treatment is fraught with controversy -- the jury is still out on some possible miscarriage causes, and many common treatments for recurrent miscarriages are not proven to work.

Note: The exact tests that your practitioner runs may be different from this list.

Testing for problems with the uterus:

• Hysterosalpingogram (HSG)
  During this imaging test, dye is injected into the uterus and an X-ray is taken; it looks for an abnormal shape of the uterus that might cause problems in pregnancy.

• Hysteroscopy
  A hysteroscopy involves inserting a thin telescope into the uterus to get the most accurate picture. A doctor may be able to repair minor problems during the test.

Blood Tests:

• Lupus Anticoagulant Antibodies
  Lupus anticoagulant antibodies are one of the markers for antiphospholipid syndrome.

• Anticardiolipin Antibodies
  Anticardiolipin antibodies are another marker for antiphospholipid syndrome.

• PT and aPTT
  PT stands for Prothrombin Time, and it is a test to see how fast the blood clots. aPTT stands for Activated Partial Thromboplastin Time, and it is another blood clotting test. Abnormal results on either might be associated with hereditary thrombophilias.

• MTHFR Gene Mutation
  Mutations in the MTHFR gene can impair the body's ability to absorb folic acid. A few studies have associated MTHFR gene mutations with increased risk of miscarriages, but most have found the gene not to be a major factor in causing miscarriages.

• Protein C, Factor V Leiden, Protein S deficiency, Prothrombin gene mutation and Antithrombin III deficiency
  These are the hereditary thrombophilias that seem to be linked to miscarriages after 10 weeks. Some doctors test for these and others do not.

• Thyroid Panel
  Some evidence suggests that hypothyroidism may increase risk of second-trimester miscarriage, but the evidence is not conclusive. Some practitioners routinely test women for thyroid issues and others do not.

• Progesterone
  The link between progesterone and miscarriages is a matter of hot debate. When doctors do test progesterone, the test usually involves a blood draw a week after ovulation, or on day 21 of a 28-day cycle.

• Karyotyping of the Parents
  This test would be performed on both parents and looks for problems in the genetic structure that might boost pregnancy loss risks, such as balanced translocation.

Other Tests:

• Fetal Tissue Karyotyping
  If a woman had a D&C for her most recent miscarriage, the doctor may want to order a chromosomal test of the tissue in order to rule out chromosomal abnormalities as a cause of the misarriages.

You may have mixed feelings about seeking testing. Recurrent miscarriages can put you in the strange position of actually wanting to find something wrong with you, because putting a name to the problem and having a potential treatment might make the idea of the next pregnancy seem a little less scary. Some women even feel scared to proceed with testing because they’re afraid they won’t find answers.

If you feel that way, it’s understandable, but try to remember that even if you don’t get answers, you should feel some reassurance that at least you can try again knowing that you do not have a known medical problem to get in the way of your having a successful pregnancy. Even though statistics may not be reassuring, studies indicate that 70% of couples who have recurrent miscarriages without a known cause do eventually go on to have a successful pregnancy. So the odds are still high that someday this ordeal that you are going through right now will just be a bad memory.

Information on Specific Diagnoses:

Balanced Translocation
Balanced Translocation Support group

Factor V Leiden
Factor V Leiden

MTHFR
MTHFR
MTHFR