Reduced fetal movements at term in singleton low risk pregnancies—Is there an association with placental histopathological findings?

Introduction: Maternal perception of fetal movements has long been considered an indicator of fetal well-being. A sudden decrease in the number of fetal movements is suggestive of fetal compromise. We aimed to determine whether the maternal perception of reduced fetal movements (RFM) is associated with placental pathological lesions in a low-risk term population. Material and methods: Our study was a case-control study that was performed in a single university center. Placental histopathology, maternal demographics, labor characteristics, and neonatal outcomes of term, singleton pregnancies with maternal perception of RFM during the 2 weeks prior to delivery were collected. To isolate the effect of RFM on placental pathology, we excluded cases complicated by preterm birth, hypertensive disorders, diabetes mellitus, small-for-gestational-age and congenital/genetic anomalies. We compared pregnancy outcomes and placental pathology between the RFM group and a control group matched for gestational age and mode of delivery. Placental lesions were classified according to the “Amsterdam” criteria. Composite adverse neonatal outcome was defined as one or more of the following: sepsis, transfusion, hypoglycemia, phototherapy, respiratory morbidity, cerebral morbidity, necrotizing enterocolitis and fetal/neonatal death. Multivariable regression analysis was performed to identify independent associations with adverse neonatal outcome. Results: We included patients who gave birth from January 2008 until May 2019. The study group included 203 term pregnancies with RFM during the 2 weeks prior to delivery, which was matched with 203 controls. The RFM group was characterized by a higher rate of placental weight <10th percentile (22.6% vs. 3.9%, P <.001), a higher rate of maternal vascular malperfusion lesions (30.5% vs. 18.7%, P =.007) and lesions of maternal inflammatory response (43.3% vs. 29.5%, P =.005). At delivery, the RFM group had higher rates of cesarean delivery due to non-reassuring fetal heart rate monitoring (P =.01), 5-minute Apgar score ≤7 (P =.03), neonatal intensive care unit admissions (P <.001) and composite adverse neonatal outcomes (P =.007). Using multivariable analysis, RFM (adjusted odds ratio [aOR] 1.7, 95% confidence interval [CI] 1.1-4.8), and placental maternal vascular malperfusion lesions (aOR 1.2, 95% CI 1.0-2.9) were independently associated with adverse neonatal outcome. Conclusions: After excluding important placental-related morbidities, RFM was associated with a higher rate of placental weight <10th percentile and placental maternal vascular malperfusion lesions vs. controls. This study suggests a placental involvement in the association between RFM at term and adverse pregnancy outcomes.