One of the most difficult subjects to discuss—especially for those treating or experiencing infertility—is miscarriage. Yet not talking about it often leads to unnecessary guilt, exacerbated shame and all too often to treatments of questionable value. So let’s review some of the most recent findings about this challenging topic in order to foster better communication and improved outcomes.
Miscarriage occurs in at least one out of every five pregnancies. Most of these miscarriages—estimated to be 60% to 80% depending on the woman’s age—are due to a genetic abnormality in the developing fetus. Yet a recent national survey demonstrated that both men and women in the USA believe that miscarriage is rare; occurring in fewer than 6% of pregnancies. Even worse, the same respondents felt that lifting heavy objects and stressful events were among the most common causes of pregnancy loss. Maybe this false sense of responsibility explains why feelings of guilt and shame are so frequently reported by patients following a miscarriage. So let’s set the record straight by reviewing what the science has taught us.
For a successful pregnancy to occur there are three critical factors. First, there must be a healthy, genetically competent embryo. Then the embryo must arrive into the woman’s uterus during the hormonally synchronized window of time to support implantation. Finally the blood flow to the implantation site and woman’s immunologic functions must foster the growth of the pregnancy along with providing continued hormonal support. So let’s consider what interventions we can take to assist women with recurrent pregnancy loss (REPL)—defined as at least two pregnancy losses—to improve their chance of delivering a healthy baby.
In general, REPL is fairly uncommon and occurs in less than 5% of women. However, it is becomes increasingly more frequent after the age of 35 due to the increased likelihood of producing genetically abnormal embryos associated with aging. Comprehensive chromosomal screening (CCS) involves performing a biopsy on developing embryos created through IVF. These biopsies can then be tested for missing or extra copies of all 24 (including X & Y) chromosomes in each embryo—the most common cause of miscarriage. Several studies have demonstrated that doing so can reduce the risk of miscarriage substantially. In fact, one recent study performed on women with REPL demonstrated that selecting and transferring only genetically competent embryos reduced the subsequent miscarriage rate to around 7%; making it three to five times less common than women that did not undergo this important test. So taking steps to insure that a pregnancy is started with an apparently healthy embryo is an effective strategy but some argue that it is too costly. Given that about half of the women with REPL are never given a diagnosis explaining why their pregnancy loss occurred; the insight gained from CCS might be considered invaluable. In fact, the lack of this diagnostic information likely fuels many of the other—often unnecessary—treatments offered to prevent subsequent miscarriage.
It has long been theorized that decreased blood flow and inflammation were major contributors to pregnancy failure and that low dose aspirin would help correct these problems. Unfortunately a randomized study involving over 1200 women with REPL demonstrated that using low-dose aspirin (started before conception) was no better than placebo in reducing the risk of subsequent miscarriage. Given that low-dose aspirin is inexpensive; many may continue to use it anyway on the outside chance that it may help some individuals with REPL even though it is clearly not a major preventative measure for most women. However, other more expensive and risky treatments are often suggested as well.
Since immunologic problems have long been theorized to contribute to recurrent pregnancy loss, treatment with intravenous immunoglobulin (IVIG) has been proposed for nearly two decades to modulate the immune response. In truth this expensive and potentially hazardous treatment has failed to show benefit in multiple studies. Nonetheless, it has recently been put to the test yet again. This time the study was a larger prospective, randomized trial where both the patients and their providers were blinded as to whether they were receiving the actual treatment or a placebo. The group studied included 82 patients that had each experienced four or more miscarriages in previous attempts at conception. Unfortunately, the live birth rate was no different between the treatment group and the placebo group. This is yet another study demonstrating that immunologic therapy is not likely to help most REPL patients.
Another strategy to reduce inflammation and improve blood flow as well as boosting health in general is to look at the patient’s diet and lifestyle. Obesity is associated with an increase in miscarriage risk as well as a higher risk of nearly every pregnancy related complication. Recently the Nurse’s Health Study II —a prospective monitoring of over 17,000 women that had conceived over 25,000 pregnancies provided some helpful insight. They found that pre-pregnancy weight gain and obesity were associated with a higher risk of miscarriage. So helping overweight or obese women with REPL to lose weight prior to pregnancy may be one of the best ways to help them have a baby as well as a healthier life.
Sharing the latest research on miscarriage is critical. Not only can it reassure and empower women but also help them avoid further heartache. It can also help prevent them from making emotionally based decisions to pursue treatments that may even cause further harm as well as financial hardship.