Unexpected term NICU admissions: a marker of obstetrical care quality?

Background: Unexpected admissions of term neonates to the neonatal intensive care unit and unexpected postnatal complications have been proposed as neonatal-focused quality metrics for intrapartum care. Previous studies have noted significant variation in overall hospital neonatal intensive care unit admission rates; however, little is known about the influence of obstetric practices on these rates or whether variation among unanticipated admissions in low-risk, term neonates can be attributed to systemic hospital practices.

Objective: The objective of the study was to examine the relative effects of patient characteristics and intrapartum events on unexpected neonatal intensive care unit admissions and to quantify the between-hospital variation in neonatal intensive care unit admission rates among this group of neonates.

Study design: We performed a retrospective cross-sectional study using data collected as part of the Consortium for Safe Labor study. Women who delivered term (≥37 weeks), singleton, nonanomalous, liveborn infants without an a priori risk for neonatal intensive care unit admission were included. The primary outcome was neonatal intensive care unit admission among this population. Multilevel mixed-effect models were used to calculate adjusted odds ratios for demographics (age, race, insurer), pregnancy characteristics (parity, gestational age, tobacco use, birthweight), maternal comorbidities (chronic and pregnancy-induced hypertension), hospital characteristics (delivery volume, hospital and neonatal intensive care unit level, academic affiliation), and intrapartum events (prolonged second stage, induction of labor, trial of labor after cesarean delivery, chorioamnionitis, meconium-stained amniotic fluid, and abruption). Intraclass correlation coefficients were used to estimate the between-hospital variance in a series of hierarchical models.

Results: Of the 143,951 infants meeting all patient and hospital inclusion criteria, 7995 (5.6%) were admitted to the neonatal intensive care unit after birth. In the fully adjusted model, the factors associated with the highest odds for neonatal intensive care unit admission included: nulliparity (adjusted odds ratio, 1.62 [95% confidence interval, 1.53-1.71]), large for gestational age (adjusted odds ratio, 1.59 [95% confidence interval, 1.47-1.71]), and small for gestational age (adjusted odds ratio, 1.60 [95% confidence interval, 1.47-1.73]). Induction of labor (adjusted odds ratio, 0.95 [95% confidence interval, 0.89-1.01]) was not associated with increased odds of neonatal intensive care unit admission compared with women who labored spontaneously. The events associated with higher odds of neonatal intensive care unit admission included: prolonged second stage (adjusted odds ratio, 1.66 [95% confidence interval, 1.51-1.83]); chorioamnionitis (adjusted odds ratio, 3.89 [95% confidence interval, 3.42-4.44]), meconium-stained amniotic fluid (adjusted odds ratio, 1.96 [95% confidence interval, 1.82-2.10]), and abruption (adjusted odds ratio, 2.64 [95% confidence interval, 2.16-.21]). Compared with women who did not labor, the odds of neonatal intensive care unit admission were lower for women who labored: adjusted odds ratio, 0.48 (95% confidence interval, 0.45-0.52) for women with no uterine scar and adjusted odds ratio, 0.83 (95% confidence interval, 0.73-0.94) for women with a uterine scar. There was significant variation in neonatal intensive care unit admission rates by hospital, ranging from 2.9% to 11.2%. After accounting for case mix and hospital characteristics, the between-hospital variance was 1.9%, suggesting that little of the variation was explained by the effect of the hospital.

Conclusion: This study contributes to the currently limited understanding of term, neonatal intensive care unit admission rates as a marker of obstetrical care quality. We demonstrated that significant variation exists in hospital unexpected neonatal intensive care unit admission rates and that certain intrapartum events are associated with an increased risk for neonatal intensive care unit admission after delivery. However, the between-hospital variation was low. Unmeasured confounders and extrinsic factors, such as neonatal intensive care unit bed availability, may limit the ability of unexpected term neonatal intensive care unit admissions to meaningfully reflect obstetrical care quality.