The role of angiogenic markers in adverse perinatal outcomes: fresh versus frozen embryo transfers

We aimed to investigate the angiogenic balance in fresh compared to frozen embryo transfers, and among neonates with adverse perinatal outcomes. This was a retrospective cohort study. All IVF cycles resulting in a singleton live birth at a university academic fertility center from January 1, 2011, to December 31, 2013, were examined. Concentrations of sFLT-1 and PlGF were measured in previously frozen serum specimens collected during early gestation at approximately 5 weeks gestation. Patients completed an electronic survey to detail perinatal outcome. We identified 152 singleton live births (103 fresh, 49 frozen). Demographic characteristics were similar between the two groups. Ratios of sFlt-1:PlGF were not different between fresh and frozen transfers. Neonates from fresh cycles had a mean birth weight 202 g lighter (p = 0.01) than frozen cycles, after adjusting for gestational age. Among babies born with poor perinatal outcomes, there was a difference in sFlt-1:PlGF ratios after adjusting for race. In non-Asians, infants born small for gestational age (SGA) (< 10th percentile) had significantly higher sFLT-1:PLGF ratio, median ratio (0.21 vs 0.12, p = 0.016). Fresh transfers were associated with lower birth weight infants compared to frozen transfers. While there was no difference in sFlt-1:PlGF ratios between fresh and frozen transfers, these ratios were significantly lower in SGA infants, suggesting an imbalance in angiogenic markers during placentation.