Recurrent pregnancy loss is a condition when a woman has two or more clinical pregnancy losses (miscarriages) before 20 weeks of gestation. A clinical pregnancy loss occurs after a pregnancy has been visualized on an ultrasound examination and can occur as early as 5-6 weeks’ gestation (1-2 weeks after a missed period). A “biochemical pregnancy” occurs when a urine or blood pregnancy test is found to be positive but declines and becomes negative before a clinical pregnancy can be seen on ultrasound. Biochemical losses are not usually included in making a recurrent pregnancy loss diagnosis.
There are a variety of reasons why women may have recurrent pregnancy loss:
Many early miscarriages (the ones that happen in the first 3 months of pregnancy) are due to genetic abnormalities in the embryo. There are 46 chromosomes in a normal embryo. When the embryo has an extra chromosome or one is missing, the pregnancy is likely to end in miscarriage. Chromosome abnormalities occur in up to 60% of first-trimester miscarriages. Such genetic abnormalities typically do not allow development into a healthy baby. The risk of miscarriage due to these genetic abnormalities increases from 10%-15% in women younger than 35 to more than 50% in women older than 40.
In about 5% of couples with recurrent pregnancy loss, one of the parents has a rearrangement (translocation) of their chromosomes. If one parent has a translocation, this can result in embryos with chromosome imbalances that are more likely to miscarry. The parents’ blood can be studied (karyotyped) to see if they have a translocation. If a chromosomal problem is found, the doctor might recommend genetic counseling. While many couples with translocations eventually conceive a healthy pregnancy naturally, your doctor might suggest fertility treatments, such as in vitro fertilization (IVF).
Stopping cigarette smoking and stopping illicit drug use will lower the risk for miscarriage. Limiting alcohol and caffeine intake may also be helpful. Obesity or being overweight has been linked with increased risk of miscarriage, so healthy weight loss might also help pregnancy outcomes. There is no clear scientific proof that stress, anxiety, or mild depression causes recurrent pregnancy loss. However, these are important problems that are common in women with recurrent pregnancy loss. Psychological support and counseling can help couples cope with the emotional pain of miscarriage and create a healthy environment for a pregnancy.