The sadness that comes after the loss of a pregnancy certainly may turn into hopelessness or a need to protect your own emotional well-being after two or more lost pregnancies. While this is understandable, it’s important to know that many women in this situation will go on to have a successful pregnancy, even if there is no particular medical diagnosis made after an evaluation.
Facts and statistics
A miscarriage occurs in 10-15% of pregnancies before 20 weeks. Most of these miscarriages occur randomly when an embryo receives an abnormal number of chromosomes during fertilization. This type of genetic problem happens by chance; there is no modifiable medical condition that causes it. After one miscarriage, the risk of miscarriage remains the same for the next pregnancy. This means that if we use 15% as the likelihood of miscarriage, then we would expect that (15% x 15% = 2.25%) 2 out of every 100 healthy women with two pregnancies will have a miscarriage both times. However, after two consecutive pregnancy losses the risk of further miscarriage increases to 17-31%1,2.
Many physicians start an evaluation after two miscarriages even though the American College of Obstetricians and Gynecologists doesn’t suggest a medical evaluation until after the third miscarriage. This suggestion is based on statistics, however, not many women want to hear about statistics after suffering through two miscarriages. From a medical standpoint, recurrent pregnancy loss is defined as three or more consecutive losses of pregnancy prior to 20 weeks.
The evaluation for recurrent pregnancy loss starts with a physical exam and history that is focused on endocrine, genetic, pelvic organ, and autoimmune abnormalities. The most frugal way to approach this is to start with lab tests, then complete an anatomical study, and finally, a genetic karyotype if previous tests showed no abnormalities.
Thyroid function may be assessed with a TSH, Free T4 and thyroid peroxidase antibodies. Both hyper- and hypothyroid patients have an increased risk for miscarriage. Thyroid peroxidase antibodies should be checked, even in those women with a normally functioning thyroid, as a high level alone is associated with fetal loss. These tests cost about $150, in total, from my local lab.
Anti-phospholipid syndrome is an autoimmune disease that results from antibodies binding serum proteins that lead to changes in the clotting cascade and an increase in the smooth muscle tone of the blood vessels. This combination increases a person’s risk for blood clots and miscarriage. Suggested labs include anticardiolipin and anti-ß2-glycoprotein I antibodies and lupus anticoagulant testing. These tests cost about $1,300 from my local lab.
There are other labs that may indicate an organic cause for recurrent miscarriage. However, in the face of no previous symptoms for the disease, these tests are much less likely to yield a helpful result.
Sonohysterography vs Hystersalpingogram- The goal of either of these radiology studies is to define the uterine anatomy while searching for abnormalities that could cause recurrent pregnancy loss. The suggested study will be dependent on your physician’s preference. Sonohysterography may take place in your physician’s office and is, basically, a transvaginal ultrasound done while saline is infused into the uterus. The cost should be less than $1,000 and has relatively few side effects. Hysterosalpingography is done at an imaging center/hospital and is short movie, made by multiple xrays taken in a short period of time, of fluid that can be seen on xray moving through the uterus. The cost is likely greater than $1,000 and side effects include exposure to contrast media and radiation.
A karyotype costs around $400 per person. This is a genetic study from a blood sample that has limited value, relative to other studies, in the prognosis of a couple’s chance of conceiving. It is performed to look for abnormalities from the parents that may be passed to a fetus and lead to miscarriage. This study may be performed on the product of conception as well.
If your diagnostic workup shows an abnormality please don’t lose hope. A study of 155 couples with two or more consecutive pregnancy losses showed that 71% of the couples with abnormalities found in the diagnostic evaluation went on to have a live birth and the likelihood of live birth was 77% for couples whose diagnostic evaluation was normal3.
1. Recurrent miscarriage.Stirrat GM. Lancet. 1990;336(8716):673.
2. American College of Obstetricians and Gynecologists. Management of recurrent early pregnancy loss. ACOG practice bulletin no. 24, American College of Obstetricians and Gynecologists, Washington, DC 2001.
3. Etiology of recurrent pregnancy losses and outcome of subsequent pregnancies. Harger JH, et al. Obstet Gynecol. 1983;62(5):574.