Does a Nonreassuring Fetal Heart Rate Pattern Impair Renal Function in Neonates Prenatally Diagnosed with Congenital Anomalies of the Kidneys and Urinary Tract?

Objective: This study aimed to determine the effect of nonreassuring fetal heart rate (NRFHR) patterns in labor on the postnatal renal function of neonates with a prenatal diagnosis of congenital anomalies of the kidney and urinary tract (CAKUT). Study Design: A retrospective cohort study was conducted in a single tertiary referral center between 2012 and 2020. All cases with a prenatal diagnosis of CAKUT were extracted, and their fetal, maternal, obstetrical, and neonatal characteristics were analyzed. Cases of multiple gestations, preterm delivery, small for gestational age, major associated malformations or genetic aberrations, and prelabor acute obstetrical events were excluded from the analysis. The study group was comprised of patients who experienced NRFHR during labor. The control groups included (1) patients who had a trial of labor with a normal fetal heart rate pattern and (2) patients who delivered by elective cesarean section (CS). The primary outcome was abnormal serum creatinine levels in the perinatal period. For statistical purposes, the CAKUT cases were classified into a low and high estimated risk for an abnormal postnatal renal outcome. A subgroup analysis of the results was performed accordingly. Results: Two hundred and fifty-six fetuses diagnosed prenatally with CAKUT comprised the study group. Among these, 214 women (83%) opted for a labor trial, while 42 (17%) chose elective CS. Within the labor trial group, 21/214 patients (9.8%) experienced NRFHR during labor. Analysis of maternal and fetal characteristics revealed no statistically significant disparities between the groups. NRFHR patterns were not associated with a deterioration in neonatal serum creatinine compared with those with normal fetal monitoring or those born by an elective CS. Conclusion: NRFHR patterns during labor and delivery did not impair neonatal renal function status in fetuses diagnosed prenatally with low- and high-risk CAKUT. Delivery can be managed according to standard obstetrical guidelines.