Antiphospholipid syndrome in pregnancy: a randomized, controlled trial of treatment

To compare the efficacy of low-dose aspirin alone versus low-dose aspirin plus low molecular weight heparin in pregnant women with antiphospholipid syndrome and recurrent miscarriage as prophylaxis against pregnancy loss.

From a regional miscarriage clinic, 119 consecutive women with persistently positive tests for lupus anticoagulant and/or anticardiolipin immunoglobulin G and M antibody were invited to participate in a randomized, controlled trial between 1997 and 2000. After ethical approval and adherence to a written protocol, 12 women were unwilling to participate, five failed exclusion/inclusion criteria, and four were nonpregnant. Laboratory analysis was performed by Sheffield University Coagulation Department, electronically generated randomization by Manchester University Centre for Cancer Epidemiology, and data collection and analysis by a research officer at Leeds University. Viability ultrasound every 2 weeks was provided until 12 weeks' gestation before transfer to the pregnancy support antenatal clinic.

Ninety-eight women were randomized before 12 weeks' gestation. Forty-seven received low-dose aspirin 75 mg daily (group A), and 51 received low-dose aspirin plus low molecular weight heparin 5000 U subcutaneously daily (group B) throughout pregnancy. There were 13 pregnancy losses and 34 live births in group A and 11 losses and 40 live births in group B. The live-birth rate was 72% in group A and 78% in group B (odds ratio 1.39, 95% confidence interval 0.55, 3.47). There were no cases of maternal thrombosis in either group.

A high success rate is achieved when low-dose aspirin is used for antiphospholipid syndrome in pregnancy. The addition of low molecular weight heparin does not significantly improve pregnancy outcome.