Association between obesity and intraoperative hypothermia in women undergoing caesarean delivery: results from a prospective cohort study

Background: Intraoperative hypothermia is associated with adverse maternal and neonatal outcomes. However, the relationship between obesity and intraoperative hypothermia remains contentious. The aim of this study was to investigate the association between obesity and intraoperative hypothermia in women undergoing caesarean delivery. Materials and methods: We prospectively recruited 705 women who underwent caesarean delivery. Patients were classified into two groups according to body mass index (BMI): non-obese group (BMI < 28 kg/m 2 ) and obese group (BMI ≥ 28.0 kg/m 2 ). The primary outcome measure was the incidence of intraoperative hypothermia, defined as a core temperature of less than 36°C. Intraoperative core temperature was measured in the bladder. Propensity score–matched analyses, multivariable logistic regression analyses, subgroup analyses, and restricted cubic splines were used to assess the association between obesity and intraoperative hypothermia. Results: After propensity score matching, 244 matched pairs were selected for analysis. Participants in the obese group exhibited a significantly lower incidence of hypothermia compared to those in the non-obese group (27.5% vs. 38.9%; P < 0.01). The incidence of need for rescue warming was lower in the obese group compared to the non-obese group (1.2% vs. 5.3%; P = 0.01). Similar findings were observed in the overall study population, the obese group was associated with a significantly decreased incidence of hypothermia when compared to the non-obese group (OR, 0.59; 95% CI, 0.41–0.83; P = 0.03). There was a non-linear association between BMI and hypothermia, with the lowest risk at a BMI of 28.4 kg.m −2 . Conclusions: Obesity was associated with a potentially lower risk and severity of intraoperative hypothermia compared with non-obese patients. Although a non-linear relationship between the degree of obesity and hypothermia was observed, the clinical significance of more severe obesity on hypothermia risk remains to be clarified.