Recurrent pregnancy loss (RPL) is the medical phrase for repeated miscarriages (more than one), which can be quite disheartening for the couple. Miscarriage occurs 20% of the time, simply due to random abnormalities. RPL is a condition distinct from infertility, and it is defined by the American Society of Reproductive Medicine (ASRM) as two or more miscarriages in a row.
Less than 5% of women experience two consecutive miscarriages, and a mere 1% will have three or more. Any couple who experiences recurrent pregnancy loss should undergo a physical evaluation and seek psychological support. A comprehensive evaluation will result in higher pregnancy success rates.
Genetic and Chromosomal Causes
The most common cause of recurrent pregnancy loss is spontaneous chromosomal abnormality, which occurs when the egg is dividing. The risk of miscarriage increases with the woman’s age, and by age 40-45 years, there is a 40-60% chance of miscarriage. After age 40, more than one-third of pregnancies result in miscarriage.
Many embryos have an abnormal of chromosomes, and around 80% of all miscarriages occur during the first trimester due to chromosomal abnormalities, such as monosomy (lacking a chromosome) or trisomy (having an extra chromosome). A blood test is used for both partners to identify chromosomal translocation, which is relocation of a segment of genes.
Fibroids, Polyps, and Uterine Disorders
To evaluate for uterine disorders, the workup involves a pelvic ultrasound, hysteroscopy, and hysterosalpingogram. These tests are used to diagnose any congenital abnormalities or distortions of the uterus that may cause miscarriage.
Polyps, fibroids, scar tissue, and a uterine septum are problems that could interfere with carrying a baby to term. A fibroid that invades the uterine cavity should be removed by hysteroscopy, if possible. A fibroid that is seven centimeters or larger may require an open surgical procedure.
Another cause of RPL is abnormal blood clotting in the small placental blood vessels. A genetically determined factor called Factor V Leiden increases risk blood clots in the small vessels that supply the uterine lining. Thrombophilia is a condition that causes increased blood clots, and antiphospholipid syndrome is a production of antibodies to phospholipids, which are necessary parts of the blood vessel wall. To detect these disorders, a comprehensive laboratory test is ordered. Anticoagulation medications work to decrease clotting, such as low dose Lovenox or Heparin.
Recurrent pregnancy loss can occur due to pituitary dysfunction or thyroid disease. Women with polycystic ovarian syndrome (PCOS) have an elevated luteinizing hormone (LH) level on certain days of the menstrual cycle, which causes miscarriage. Luteal phase defect is a condition that involves insufficient levels of progesterone after ovulation. The hormone progesterone is necessary to maintain the uterine lining once the embryo implants.
A normal luteal phase is around 14 days, but with luteal phase disorder, the time is shortened. Without progesterone, bleeding occurs at odd times during the month, and the uterine lining does not sustain pregnancy. This defect is treated with progesterone and human chorionic gonadotropin (hCG) supplements.
Genetic, Infectious, and Immune Factors
One genetic mutation that contributes to miscarriage is Methylenetetrahydrofolate (MTFHR). Mutations of this gene will cause blood clots in the placenta and uterine wall, which inhibits the transport of nutrients to the developing fetus.
Female reproductive tract infections are associated with pregnancy loss. Gonorrhea and chlamydia contribute to scarring and inflammation of the fallopian tubes and uterus. In addition, excessive bacteria in the vagina can change the flora and acidity, which can lead to inflammation of the reproductive tract. Immune factors can be treated with prednisone (anti-inflammatory agent) and estrogen supplementation.