Comparison of anticoagulation regimens for pregnant women with prosthetic heart valves: A meta-analysis of prospective studies.

INTRODUCTION

Pregnancy is associated with a hypercoagulable state, which makes pregnant women with prosthetic heart valves at high risk of thromboembolism. The proper anticoagulation regimen should take both the maternal protection and the fetal outcomes into consideration. However, no consensus on the present anticoagulation regimen for those women has been reached yet, especially in the first trimester of pregnancy.

AIMS: The present meta-analysis is conducted to compare anticoagulation efficiency and feto-maternal complications of heparin and warfarin in the first trimester.

RESULTS

Databases of MEDLINE, EMBASE, and the Cochrane Library were systematically searched (all from their inception to October 2016) for cohort studies reporting the outcome of anticoagulation in pregnant women with mechanical heart valves. Seven relevant prospective studies were identified for inclusion in the present meta-analysis. The forest plots indicated that warfarin was more effective in prevention valve thrombosis in the first trimester than heparin (OR: 14.58; 95% confidence interval [CI]: 3.94-53.94; P < .0001; I2  = 0%). The spontaneous abortion between the two regimens was not statistically different (OR: 1.42; 95% CI: 0.80-2.49; P = .23; I2  = 20%), which indicated that heparin could not provide better protection to the fetus in the early stage of pregnancy than warfarin. The incidence of warfarin embryopathy was low, and it only occurred in a twin among all the included cases.

CONCLUSIONS

The present meta-analysis indicated that warfarin can provide better protection for the mother and the teratogenic effects may be overestimated. Heparin does not ensure better fetal outcomes as it is associated with severe adverse maternal outcomes, including mortality.