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.