Abstract
: A 35 year old woman with recurrent severe placenta mediated pregnancy complications in her 2 pregnancies asks: Will low molecular weight heparin help prevent recurrent placenta mediated pregnancy complications in my next pregnancy? We performed a meta-analysis of randomised controlled trials (RCTs) comparing low molecular weight heparin (LMWH) versus no LMWH for the prevention of recurrent placenta-mediated pregnancy complications. We identified six RCTs, including a total of 848 pregnant women with prior placenta-mediated pregnancy complications. The primary outcome was a composite of PE, birth of a SGA newborn (<10th percentile), placental abruption, or pregnancy loss >20 weeks. Overall, 67/358 (18.7%) of women on prophylactic LMWH had recurrent severe placenta-mediated pregnancy complications, as compared with 127/296 (42.9%) women with no LMWH [relative risk reduction 0.52 (95% CI 0.32-0.86) (p=0.01) (I(2) 69% indicating moderate heterogeneity)]. We identified similar relative risk reductions with LMWH for individual outcomes including any PE, severe PE, SGA <10th, SGA <5th, preterm delivery <37 weeks and preterm delivery <34 weeks with minimal heterogeneity. Low molecular weight heparin may be a promising therapy for recurrent, especially severe, placenta mediated pregnancy complications but further research is required.