Pregnancy Problematic in Mechanical Heart Valve Recipients

Pregnancy in women with prosthetic heart valves results in live births in only about two thirds of cases, Lebanese researchers report in the September issue of the American Journal of Obstetrics and Gynecology.

“Regardless of the treatment modality used for anticoagulation, there is still a substantial risk of thromboembolic complications during pregnancy in such women,” lead researcher Dr. Anwar H. Nassar told Reuters Health.

“Oral anticoagulants (warfarin) are associated with the highest risk of spontaneous abortion and lowest live birth rate compared to heparin or combination of both medications,” Dr. Nassar added.

Dr. Nassar and colleagues at the American University of Beirut Medical Center in Lebanon came to these conclusions after a retrospective review of 82 pregnancies in 33 women with mechanical valve prostheses. Heparin was used during 9 pregnancies, warfarin was used in 30, and the agents were used in combination during 43 of the pregnancies.

Overall, 65.9% of pregnancies resulted in live births. There were 12 spontaneous abortions, 7 therapeutic abortions and 9 stillbirths. None involved patients who received heparin alone.

There were no maternal deaths, but two patients on heparin and one on warfarin had mitral valve thrombosis. Surgery was required in one patient and thrombolysis in the other two. In addition, one warfarin patient and four combination patients had peripartum hemorrhage that required transfusion.

Given these findings, Dr. Nassar concluded that “the benefits and the risks of each medication should be carefully weighed before deciding on the best treatment to be used.”

Am J Obstet Gynecol 2004;191:1009-1013.