Cesarean delivery at term for non-reassuring fetal heart rate tracing: risk factors and predictability

To delineate risk factors for adverse outcomes among those who underwent cesarean delivery (CD) for non-reassuring fetal heart rate tracing (NRFHT) and ascertain whether neonatal or maternal morbidity can be predicted accurately.

The Consortium on Safe Labor Database was utilized for this secondary analysis. Inclusion criteria were non-anomalous, singleton gestations between 37.0 and 41.6 weeks who underwent CD for NRFHT. Composite adverse neonatal outcomes (CANO) included Apgar <5 at 5 min, seizures, mechanical ventilation, sepsis, intraventricular hemorrhage, necrotizing enterocolitis or neonatal death. Composite adverse maternal outcomes (CAMO) included endometritis, blood transfusion, wound complication, admission to intensive care unit, thromboembolism, hysterectomy or death. Bivariable analysis and multivariable Poisson regression were used to identify risk factors independently associated with adverse outcomes. Receiver operating characteristic (ROC) curves were created to evaluate the predictive value of the models for adverse outcomes.

Of 228,438 births in the database, 7310 individuals (3.7%) met inclusion criteria. Among this cohort, CANO occurred 3.8% of the time. CANO was less common among people over 35 years (9.8% versus 18.4% p < .01) but was more common among those with at least high-school education (15.3% versus 11.2%; p < .01), varying by ethnicity (p < .01). CAMO occurred in 3.4% and was less common among those undergoing induction of labor (37.3% versus 49.4%; p < .01) and more common among those with clinical chorioamnionitis (8.4% versus 4.3%; p < .01). The area under the curve (AUC) for ROC curve to identify CANO was 0.63 implying a limited ability to predict neonatal adverse outcomes. The AUC for identifying women with maternal adverse outcomes was 0.69 also indicating a moderate prediction ability.

Among singletons between 37 and 41 weeks who labored, the rate of CD for NRFHT was about 3.7% and among them CANO occurred in 3.8%. While risk factors for adverse neonatal outcomes following CD for NRFHT are identifiable, they do not suffice to predict them.