Recurrent miscarriage (also known as recurrent pregnancy loss) is strictly defined as three or more failed pregnancies but is most often defined as two or more losses by many experts. Most reproductive endocrinologists will initiate investigations to see if the cause can be determined, and possibly treated, once a woman has had two consecutive miscarriages.
Two consecutive miscarriages occur in up to 5% of couples trying to conceive.
General recommendations in couples with recurrent miscarriage include: smoking cessation, reduced alcohol and caffeine consumption, moderate exercise, and weight control with a healthy lifestyle. Supplementation of the woman’s diet with prenatal vitamins and extra folic acid is recommended.
In addition to this, our center can provide referrals to therapists who may help couples cope with the feelings of loss, grief, and helplessness that are often associated with recurrent miscarriage.
Potential causes, tests and treatments for these include:
Random chromosomal abnormalities in the fetus
These occur in over 70% of otherwise unexplained miscarriages and the rate increases with age. In the female under age 35 the chance of any pregnancy miscarrying is 14% and after age 40, it is 40%.
Test: Chromosome testing of the fetal tissue.
Treatment: None. IVF with embryo biopsy and chromosomal testing has not yet been shown to improve ongoing pregnancy rates, but this may change as better technologies become available. Women over 40, with no other demonstrable cause for pregnancy loss, may consider use of donor eggs from a younger woman.
Chromosomal abnormalities in the parents
These can be result in severe chromosomal abnormalities of the fetus, which may cause the fetus to arrest in development and miscarry. This is a rare cause of recurrent miscarriage, occuring in less than 5% of couples.
Test: Blood test for chromosomes on each of the parents.
Treatment: IVF with embryo biopsy to identify the aberrant chromosome and transfer of only unaffected embryos to the woman’s uterus.
Tests: Blood hormone levels for thyroid function, prolactin, and assesment for irregular ovulation and polycystic ovary syndrome.
Treatment: Medication as required to normalize thyroid levels, lower prolactin levels or induce normal ovulation (often combined with supplemental progesterone after ovulation).
Metabolic aberrations, such as diabetes
Tests: Blood sugar testing
Treatment: Medication and diet alterations to normalize blood sugar levels.
Uterine abnormalities, such as a septum (wall which a woman is born with, down the center of the uterus), abnormal growths in the cavity of the uterus, such as fibroids or polyps, and scar tissue in the uterine cavity. All of these can cause a poor environment for embryo implantation.
Tests: Hysterosalpingogram (Xray dye test), saline infusion sonogram (ultrasound of the uterus using saline to outline the cavity), hysteroscopy (placement of a small telescope into the uterine cavity to assess its architecture).
Treatment: If possible, uterine surgery to correct the architectural abnormality, e.g.incision of a septum, removal of polyps or fibriods, or removal of adhesions.
Phospholipids are felt to be important for adequate placental development and antibodies to these, including anticardiolipin antibody and lupus anticoagulant, account for 3% to 15% of recurrent miscarriages.
Tests: Blood tests for antiphospholipid antibodies, in particular anticardiolipin antibody and lupus anticoagulant.
Treatment: Studies had shown some benefit from use of low dose aspirin and low dose heparin (an anticoagulant) when levels of antibodies are high.
These are inherited disorders of coagulation that increase a person’s chances of devloping blood clots. These are usually associated with fetal loss in the second half of pregnancy. However, if these are tested for and are present, treatment is sometimes initiated with low dose aspirin and heparin. There are no studies to show a significant benefit from these medications when losses have been in the first trimester; these are ususally of benefit if losses have been later in the pregnancy.
Immune rejection of the fetus has been postulated as a cause of recurrent miscarriage. However, no testing has proven this and well designed clinical trials of infusion of paternal white blood cells or infusion of intravenous immune globulin (IVIG) have shown no benefit from either of these treatments.
There is increasing evidence that abnormal sperm DNA may affect embryo development and increase miscarriage rate.
After all testing is completed, no explanation is found in 50% to 75% of couples with recurrent pregnancy loss. However, studies have shown that the likelihood of subsequent live birth is 60% to 70% in these couples.