The association of maternal intrapartum subfebrile temperature and adverse obstetric and neonatal outcomes

Background Subfebrile intrapartum maternal temperature is very common, yet there is sparse evidence regarding its causes or its effects on perinatal outcomes. We examined whether mild temperature elevation during labour is a risk marker for adverse obstetric and neonatal outcomes. Methods A retrospective cohort analysis including 42 601 term, singleton live-births in two medical centres between 2003 and 2010 was performed. This study compared women who experienced a maximal intrapartum temperature of ≤37°C with women who experienced subfebrile intrapartum temperature (37.1-37.9°C). Adjusted risks for adverse obstetric and neonatal outcomes were calculated by using multivariable logistic regression models. Results Compared with maternal temperature ≤ 37°C, subfebrile temperature was associated with higher rates of primary caesarean deliveries {adjusted odds ratios [aOR] = 1.36 [95% confidence interval (CI) 1.25, 1.49])} and assisted vaginal deliveries (aOR = 1.20 [95% CI 1.11, 1.30]), as well as with greater risks of early neonatal sepsis (aOR = 2.66 [95% CI 1.88, 3.77]), neonatal intensive care unit admissions (aOR = 1.40 [95% CI 1.08, 1.83]), and neonatal asphyxia or seizures (aOR = 3.18 [95% CI 1.51, 6.70]). Mildly elevated maternal intrapartum temperature (37.1-37.5°C) was also associated with adverse outcomes. Conclusions Maternal intrapartum subfebrile temperature may be an indicator of operative delivery and neonatal morbidity. Further research is needed to confirm these findings and to reveal underlying mechanisms.