Larger studies need to be undertaken in order to define the risks and benefits of enoxaparin – a form of the blood thinner heparin – in women at risk for blood clots after caesarean birth, said Baylor College of Medicine researchers in a report that appears in the current issue of the journal Obstetrics & Gynecology.

This research was spurred by expert recommendations on the preventive use of blood thinners following surgery among women at highest risk for blood clots (also called venous thromboembolism). Because such blood clots are life threatening, and pregnancy poses additional risk, many experts have adopted guidelines that call for the use of enoxaparin as a preventive treatment in new moms following cesarean delivery. However, this issue has not been fully addressed with rigorous medical research.

Risks and benefits

In order to gain an initial grasp on the potential risks and benefits of enoxaparin, BCM researchers working at the Harris County Hospital District's Ben Taub General Hospital studied how women fared after undergoing caesarean birth. In the study, Dr. Kjersti Aagaard, an assistant professor of obstetrics and gynecology at BCM and the senior author of the study, and her colleagues evaluated the health after birth of 1,677 women who underwent caesarean birth over a 23-month period. All were considered at increased risk for blood clots, yet 653 received enoxaparin and 1,024 did not.

They found that 6.8 percent of women in the treated group developed minor wound complications (like skin separation), while 3.6 percent of those who did not receive treatment (but should have according to the guidelines) did not. In the treated group, 2.1 percent were rehospitalized after discharge compared to 0.8 percent in those who did not receive the preventive treatment. However, there was a higher rate of venous (in the vein or lungs) blood clots among those who did not receive the drug, but it was not statistically significant.

Definitive study needed

"Our findings suggest that while there were modest risks to enoxaparin prophylaxis, there was also a non-significant but clinically appreciable benefit for the prevention of DVT (deep vein thrombosis). Until an adequately powered, multi-centered, randomized trial is executed, we cannot definitively answer the question of whether the risk of this treatment outweighs the benefits," said Aagaard.

Current guidelines developed by experts recommend that women at risk for developing venous blood clots receive enoxaparin after caesarean, and Aagaard said that physicians should continue to follow those recommendations until a definitive study can be completed.

Others who took part in the study include Dr. Millie A. Ferres, Dr. Sofia A. Olivarez, Victoria Trinh, Dr. Christina Davidson and Dr. Haleh Sangi-Haghpeykar, all of BCM.

Funding for this research came from the National Institutes of Health New Innovator Award to Aagaard.