Pregnancy outcomes in correlation with placental histopathology in pregnancies complicated by fetal growth restriction with vs. without reduced fetal movements

Abstract Purpose: Fetal movements are crucial indicators of fetal well-being, with reduced fetal movements (RFM) suggesting potential fetal compromise. Fetal growth restriction (FGR), often linked to placental insufficiency, is a major cause of perinatal morbidity and mortality. This study aimed to investigate the neonatal, labor, and placental outcomes of FGR pregnancies with and without RFM at term. Methods: In this retrospective study, data from all term, singleton deliveries with FGR and concomitant RFM were obtained and compared to an equal control group of FGR without RFM. Maternal characteristics, pregnancy and neonatal outcomes, and placental histology were compared. The primary outcome was a composite of adverse neonatal outcomes. A multivariable regression analysis was performed to identify independent associations with adverse neonatal outcomes. Results: During the study period, 250 FGR neonates with concomitant RFM and an equal control group were identified. The groups did not differ in maternal demographics aside from significantly higher rates of maternal smoking in the RFM group (p<0.001). Polyhydramnios and oligohydramnios (p=0.032 and p=0.007, respectively) and meconium-stained amniotic fluid (p<0.001) were more prevalent in the FGR+RFM group. Additionally, the RFM group showed higher rates of adverse neonatal outcomes despite having larger neonates (p=0.047 and p<0.001, respectively). No significant differences were observed in placental findings. Logistic regression identified RFM as an independent predictor of adverse neonatal outcomes (aOR 2.45, 95%CI 1.27-4.73, p=0.008). Conclusion: Reduced fetal movements are significant and independent predictors of worse neonatal outcomes in FGR pregnancies, suggesting an additional acute insult on top of underlying placental insufficiency.