Thrombophilia testing in patients with recurrent miscarriages or stillbirth

Mark Crowther, MD, MSc, is a professor of medicine, chair of the Department of Medicine, and Leo Pharma Chair in Thromboembolism Research at McMaster University.

Other than testing for antiphospholipid antibodies, should thrombophilia testing be performed in patients with a history of recurrent miscarriages or stillbirth?

The question of whether hereditary thrombophilias contribute to recurrent miscarriages or stillbirth is a very controversial one. Unfortunately, I run a clinic in which we see patients like this, and I would say that in the large majority of cases the Internet has led these women to be tested and they come to the clinic not with the question should they be tested, but they come to the clinic with their testing results. And that leads us to the problem of how we differentiate what is a chance finding. So, for example, in the population that I live in, ~3% to 5% of people have factor V Leiden. Therefore, ~3% to 5% of people with recurrent pregnancy loss will have factor V Leiden. The women are convinced that it’s caused their pregnancy losses. But I must say that evidence is very weak.

So I would say that I can’t give a very specific answer to this question because I rarely am in the circumstance where I’m discussing actually doing the testing. I’m usually trying to explain the results of testing.

Personally, unless there was something that led me to suspect that one of these conditions existed, for example, a strong family history of venous thromboembolism, I can’t imagine I would ever do the testing. That’s because there’s no convincing evidence that if you have a woman who’s had 3 pregnancy losses after 10 weeks and she has factor V Leiden, that the factor V Leiden actually contributed to her diagnosis and, more importantly, that any treatments we might provide would influence her outcome.