FGR is the second leading cause of perinatal mortality, being associated with approximately 30% of stillbirths (Nardozza et al. 2017). Early FGR is associated with substantial disturbances of placental implantation and fetal hypoxia, which requires fetal cardiovascular adaptation. Both maternal and fetal Doppler alterations are present, allowing for risk stratification and monitoring (Arbeille et al. 1995, Nardozza et al. 2017a). Although the precise etiology for FGR due to placental causes is unknown, placental thrombosis, infarcts and hypercoagulability are frequently seen, suggesting a role for the activation of the coagulation cascade in the genesis of FGR (Elder et al. 1976, Bellart et al. 1998, Fuke at al. 1994). Currently, the management of early FGR is limited to the monitoring of fetal Doppler parameters until the risks for preterm delivery outweight the benefits of ongoing monitoring (Seravalli et al. 2015). As such, there is a special need for effective preventive and therapeutic interventions that improve the outcomes. Low molecular weight heparin (LMWH), for its anticoagulant and anti-inflammatory properties has been suggested as a possible therapeutic agent in this setting (Tyrell et al. 1995, Yu et al. 2004, Yu et al. 2010). We will randomize the participants to two intervention arms in a one-to-one ratio, using a computer generated randomization program. The randomization will be stratified for gestational age at diagnosis of FGR (22 to 26 weeks and >26 to 32 weeks). The experimental group will be administered enoxaparin subcutaneous injections (40 mg, 4000 IU daily) and the control group will be provided standard of care. Both groups will start intervention immediately after the diagnosis of FGR, and will continue it until 36 weeks of gestation or 12 hours before delivery, whichever comes first.
Early fetal growth restriction (FGR) is associated with considerable fetal and neonatal morbimortality (Miller et al. 2008, Nardozza et al. 2017). Placental thrombosis, infarcts and hypercoagulability are frequently seen in these pregnancies, suggesting a role for the activation of the coagulation cascade in the genesis of FGR. Patients will be randomized for low-molecular weight heparin or standard of care, and the outcomes of both arms (gestational age at delivery, gestational and fetal morbidity) will be compared.