Common Treatment for Pregnant Women May Be Ineffective

Blood thinners injected during pregnancy provided no reduction in complications from blood clotting in recent study

/ Author:  / Reviewed by: Joseph V. Madia, MD Beth Bolt, RPh

(RxWiki News) A common treatment for pregnant women prone to blood clots is a daily injection of blood thinner into the stomach. It's intended to prevent pregnancy complications, but recent research suggests this treatment may not work.

New research from Canada found that injected blood thinners did not reduce complications.

"Work with an OB-GYN while managing your pregnancy."

The research was conducted by Marc Rodger, MD, senior scientist at the Ottawa Hospital Research Institute and medical professor at the University of Ottawa in Canada, and colleagues.

Dr. Rodger and associates set out to test the effectiveness of blood thinner antepartum dalteparin on pregnant women with thrombophilia, a condition marked by a tendency to develop blood clots.

Thrombophilia affects approximately one in 10 pregnant women, according to this study, and increases the risk of pregnancy loss and other complications like placenta blood clots. A common treatment is daily, self-administered shots of low molecular weight heparin (LMWH), a blood thinner, in the abdomen.

Other research pegs the incidence of thrombophilia at closer to 1 in 1000.

For this 12-year study, the researchers looked at 292 pregnant women with thrombophilia recruited from 36 medical centers in five countries. Of the group, 146 received blood thinner injections until at least 37 weeks into pregnancy. The other 143 of the study participants did not receive the blood thinner. Three women were excluded.

In the group receiving blood thinners, 25 of the 146 pregnant women experienced complications from thrombophilia. In the other group, 27 of the 143 women had complications.

Dr. Rodger and team found that treatment with blood thinners did not reduce complications in pregnant women with thrombophilia.

"These results mean that many women around the world can save themselves a lot of unnecessary pain during pregnancy," Dr. Rodger said in a press statement. "Using [LMWH] unnecessarily medicalizes a woman's pregnancy and is costly. While I wish we could have shown that LMWH prevents complications, we actually proved it doesn't help.

"These findings allow us to move on, to pursue other, potentially effective, methods for treating pregnant women with thrombophilia and/or complications from placenta blood clots.”

Andre Hall, MD, of Birth and Women's Care in Fayetteville, NC, told dailyRx News that the study results "are in direct contradiction to what is currently considered best practice."

Dr. Hall said the statistic that 1 in 10 pregnant women have thrombophilia is higher than what he has seen in the last 18 years.

"I won't be changing any of my practice habits based on this one study, however the questions raised are valid and may require additional studies to explore," he said.

The study was published online July 24 in peer-reviewed journal The Lancet.

The Canadian Institutes of Health Research and the Heart and Stroke Foundation of Canada provided funding for this research.

One author received honoraria from Leo Pharma, Bayer, and Sanofi. The other study authors did not declare any conflicts of interest.

Review Date: 
July 23, 2014
Last Updated:
July 25, 2014