Effect of embryo stage at transfer on placental histopathology features in singleton live births resulting from fresh embryo transfers

Objective: To evaluate the effect of embryo stage at transfer on placental histopathology and perinatal outcome in singleton live births resulting from fresh embryo transfers (ETs). Design: Retrospective cohort study. Setting: Not applicable. Patient(s): The study population included all live births after fresh ETs during the period from 2009 to 2017. Intervention(s): None. Main Outcome Measure(s): Primary outcomes included anatomic, inflammatory, vascular malperfusion, and villous maturation placental features. Secondary outcomes included fetal, maternal, and perinatal complications. Result(s): A total of 677 live births were included in the final analysis and were allocated to the cleavage-stage (n = 252) and blastocyst (n = 425) ET groups. After the adjustment for confounding factors, the blastocyst group was found to be associated with a higher incidence of circummarginate membranes insertion (odds ratio [OR] 1.9, 95% confidence interval [CI] 1.2-3.4), delayed villous maturation (OR 8.5, 95% CI 1.2-69.3), chorangiosis (OR 2.0, 95% CI 1.2-3.8), parenchymal calcifications (OR 10.6, 95% CI 1.4-80.2), and intrapartum nonreassuring fetal heart rate tracing (OR 2.4, 95% CI 1.3-4.5). Compared with cleavage-stage ETs, live births resulting from the blastocysts were associated with a lower incidence of velamentous cord insertion (OR 0.5, 95% CI 0.3-0.9), retroplacental hematoma (OR 0.3, 95% CI 0.1-0.8), subchorionic thrombi (OR 0.3, 95% CI 0.1-0.8), and avascular villi (OR 0.2, 95% CI 0.03-0.7). Conclusion(s): Live births resulting from fresh cleavage-stage and blastocyst ETs have different placental histopathology features, with a higher rate of intrapartum nonreassuring fetal heart rate tracing in the blastocyst group. (C) 2020 by American Society for Reproductive Medicine.

Automated summary

The study found that singleton live births resulting from fresh embryo transfers at different stages have distinct placental histopathology features and perinatal complications, with the blastocyst transfer group showing higher rates in certain indicators compared to the cleavage-stage transfer group.