Determinants of adverse neonatal outcome in vaginal deliveries complicated by suspected intraamniotic infection.

PURPOSE

Intraamniotic infection, categorized into isolated maternal fever, suspected intraamniotic infection (SII), and confirmed intraamniotic infection, is associated with neonatal morbidity. However, there is paucity of data regarding the association between intraamniotic infection duration and neonatal outcomes among term singleton vaginal deliveries. We aimed to study the risk factors for adverse neonatal outcome among vaginal deliveries complicated by SII.

METHODS

A retrospective observational study conducted at a tertiary medical center. All consecutive singleton term deliveries with SII were included between 2011 and 2019. Maternal and obstetrical characteristics were evaluated to identify risk factors for adverse neonatal outcome. Correlation between SII duration and neonatal adverse outcome was analyzed.

RESULTS

Overall, 882 were analyzed. Most women (85.4%) were primiparous. Median gestation age at delivery was 40 weeks. Median time from SII to delivery was 170 min. Adverse neonatal outcomes occurred in 113 (12.8%) of deliveries. Duration of SII was not associated with adverse neonatal outcome. Analysis for determinants of adverse neonatal outcome revealed that oligohydramnios was more common in pregnancies with adverse neonatal outcome (7/113 (6.2%) vs. 41 (5.4%) OR [95% CI] 2.47 (1.02-5.98), p = 0.03). Duration of second stage of labor was longer in the adverse outcome group (median 179 min vs. 126 min, p = 0.008). Prolonged second stage was more common in the adverse outcome group (60 (53.1%) vs. 273 (35.5%) OR [95% CI] 2.05 (1.38-3.06), p < 0.001). On logistic regression analysis, prolonged second stage was the only modifiable factor independently associated with adverse neonatal outcome [adjusted OR 2.09 (1.37-3.2), p = 0.001]. Other variables tested did not differ between groups. Only phototherapy and base excess ≥ 12 mmol/L were significantly associated with the duration of second stage of labor; for each additional hour of the second stage, the OR for the former increased by 0.34 (p = 0.008), and for the latter by 0.69 (p = 0.007).

CONCLUSION

Duration of suspected intraamniotic infection was not associated with increased neonatal morbidity among women delivering vaginally at term. Prolonged second stage was a strong independent predictor of an adverse neonatal outcome among fetuses exposed to intraamniotic infection.