Association of non-reassuring fetal heart rate and fetal acidosis with placental histopathology

ObjectiveTo investigate the association between different placental lesions and non-reassuring fetal heart rate (NRFHR) pattern and fetal acidosis in labor.Study designPlacentas from 213 women who underwent cesarean section because of NRFHR with or without fetal acidosis (pH < 7.2) were classified by histopathologic findings: consistent with maternal circulation abnormalities i.e., namely, marginal or retroplacental hemorrhage (M0), maternal underperfusion, vascular (M1) or villous changes (M2), and those consistent with fetal thrombo-occlusive disease due to vascular (F1) or villous (F2) changes. Lesions were also analyzed by maternal (MIR) or fetal (FIR) origin of inflammatory responses.ResultsCord blood pH was normal in 169 neonates (7.29 ± 0.04; control group) and <7.2 in 44 (7.10 ± 0.07; study group). The study group had higher rates of histologic chorioamnionitis; MIR was detected in 34.1% compared to17.8% of controls (p = 0.018), and FIR, in 18.2% compared to 6.5% (p = 0.016). Neonates in the study group had lower Apgar scores and longer hospitalization.ConclusionsPlacental MIR and FIR are associated with cord blood acidosis in neonates delivered by cesarean section for NRFHR tracings in labor.