Pregnancy Outcome in Women with Mechanical Prosthetic Heart Valves at their first trimester of pregnancy Treated with Unfractionated Heparin (UFH)or Enoxaparin

Background and Aim : Pregnancy increases the risks of thromboembolism for the mother and fetus inpatients with mechanical heart valves. Given the results of some studies indicating that low molecularweight heparin (LMWH), in comparison with unfractionated heparin (UFH), leads to lower incidence ofthrombocytopenia and reduced bleeding.Methods : The present clinical trial involved 31 pregnant women with mechanical heart valves at their firsttrimester (0-14 weeks) of pregnancy. To perform the study, the patients were divided into two groups, i.e.group A (LMWH group-16 patient) and group B (UFH group-15 patient).. Then, birth weight, mode ofdelivery, and gestational age at birth as well as the maternal and fetal complications were examined andcompared between the two groups.Results : The mean age of mothers in the UFH and LMWH groups was 32.67 ± 9.11 and 31.50 ± 5.81years, respectively (p-value> 0.05). The rate of maternal and fetal complications in the UFH group wassignificantly higher than that of the LMWH group. Moreover, three (20%) and one (6.3%) cases of abortionoccurred in the UFH and LMWH groups, respectively (p-value = 0.333). Furthermore, postpartum andretroplacental hematoma occurred in 20% of pregnancies in the UFH group, while the incidence rate of thementioned complications was 6.3% in the LMWH group. Three (20%) cases of thrombotic complicationsof valve were reported for the UFH group.Conclusion : According to the results of this study, the incidence rate of abortion as well as the maternaland fetal complications in the UFH group was higher than that of the LMWH group.

Keywords:

Low molecular weight heparin (LMWH) , mechanical heart valves , pregnancy , unfractionated heparin (UFH)