(123) Is maternal intrapartum low-grade fever a risk factor for maternal and neonatal adverse outcomes?

Intrapartum fever (IF) is defined as maternal temperature ≥38°C during labor and is a known risk factor for maternal and neonatal morbidity. Maternal fever between 37.5-37.9°C, although considered as low-grade fever (LG fever), could also be indicative of an underlying maternal infection. This study aims to assess the association between intrapartum LG fever and adverse maternal and neonatal outcomes.

Study Design:

This retrospective study included all nulliparous women with a singleton pregnancy who gave birth between 2014-2020. The study cohort was divided into three groups: women with low grade intrapartum fever (LG fever group), women with intrapartum fever (IF group) and a control group comprising women with a normal-range body temperature. Maternal and neonatal outcomes were compared between the groups.

Results:

A total of 15,093 nulliparous were included, with 1,294 in the LG fever group, 934 in the IF group and 12,865 controls. Compared to the control group, the IF and the LG fever groups had higher rates of post term deliveries (P< 0.001 for all). The LG fever group had higher rates of labor induction (p< 0.001), epidural (P< 0.001), longer duration of the second stage (142 ± 71 vs 109 ± 73, P< 0.001) and vacuum extractions (VE) (27% vs 17%, P< 0.001) compared to the control group. The rate of cesarean delivery (CD) did not differ between the control group and the LG fever group (p= 0.237), but was significantly increased in the IF group (p< 0.001). Compared to the control group the LG fever group had higher neonatal birth weights (3,272 ± 429 vs 3,136 ± 467, P< 0.001), higher rates of shoulder dystocia (1.3% vs 0.4%, P< 0.001) and 5 minutes Apgar score< 7 (0.9% vs 0.4%, p=0.034). Multivariate logistic regression analysis adjusted for confounders revealed that low-grade fever was independently associated with increased likelihood to deliver by VE and to have 5 minutes  Apgar score < 7.

Conclusion:

Intrapartum maternal low-grade fever is associated with maternal and neonatal adverse outcomes and therefore should be taken into consideration during labor.