The objective of this trial will be to determine whether prophylactic low-molecular weight heparin therapy in pregnant women with the heterozygous Factor V Leiden and G20210A prothrombin gene mutations thrombophilia and a history of severe preeclampsia and/or severe fetal growth restriction reduces the risk of the composite outcome of preeclampsia, fetal growth restriction, or both.

The objective of this trial will be to determine whether prophylactic low-molecular weight heparin therapy in pregnant women with the heterozygous Factor V Leiden and G20210A prothrombin gene mutations thrombophilia and a history of severe preeclampsia and/or severe fetal growth restriction reduces the risk of the composite outcome of preeclampsia, fetal growth restriction, or both. We also will assess the effect of treatment on other indicators of maternal and neonatal complications, and the growth of fetal body composition in terms of fat and lean body mass.

Inclusion Criteria:

• Previous severe preeclampsia
• Previous severe fetal growth restriction
• Heterozygous Factor V Leiden
• Heterozygous G20210A prothrombin gene mutations

Exclusion Criteria:

• renal disease
• chronic hypertension
• preexisting diabetes mellitus
• homozygosity for Factor V Leiden
• homozygosity for prothrombin G20210A mutation
• hyperhomocysteinemia
• protein C deficency
• protein S deficency
• antithrombin deficiency
• positive anticardiolipin antibodies
• positive lupus anticoagulant