Enoxaparin for the treatment of placenta-derived fetal growth restriction (GROWTH): an open-label multicenter randomized trial.

BACKGROUND

The effect of low-molecular-weight heparin, administered from the time of diagnosis of fetal growth restriction (FGR), on fetal growth and birthweight remains uncertain.

OBJECTIVES

To evaluate whether daily enoxaparin, administered from diagnosis of placenta-derived FGR up to 36 weeks of gestation or delivery, reduces the incidence of newborns with a birthweight below the 10th percentile for gestational age.

METHODS

This open-label, randomized, multicenter trial (NCT02672566) included pregnant women with a single fetus (≥22 to <34 weeks) presenting placenta-derived FGR. Participants not requiring anticoagulation were randomly assigned via a web-based system to receive either 4000 IU of enoxaparin once daily with standard care or standard care alone. The primary outcome was the incidence of newborns with a birthweight below the 10th percentile. Secondary outcomes included gestational age at delivery, estimated weekly fetal growth, time to delivery, and perinatal morbidity and mortality.

RESULTS

The study was prematurely discontinued due to insufficient recruitment. From July 2016 to November 2019, 81 participants were enrolled. The incidence of newborns with a birthweight below the 10th percentile did not differ significantly between the enoxaparin group with standard of care (27 of 40, 67.5%) and the standard of care alone group (30 of 41, 73.2%); relative risk, 0.92; 95% CI, 0.69-1.23; P = .63. No significant differences were observed between the groups regarding secondary outcomes or maternal complications.

CONCLUSION

This study found no evidence that daily prophylactic enoxaparin during the antepartum period improves fetal growth or prolongs pregnancy in the context of constituted placenta-derived FGR.