Association between body mass index and perioperative shivering after elective cesarean delivery under spinal anesthesia: a prospective observational study.

INTRODUCTION

Perioperative shivering (POS) is a common complication of spinal anesthesia (SA) during cesarean section (C/S), with incidence rates ranging from 36% to 85%. This study explored the association between third-trimester body mass index (BMI) and POS in women undergoing elective C/S under SA.

MATERIALS AND

METHODS

In this prospective cohort study, 180 pregnant women scheduled for elective C/S were categorized into three BMI groups: normal (18.5-24.9 kg/m²), overweight (25-29.9 kg/m²), and obese (≥ 30 kg/m²). Shivering severity (Crossley and Mahajan scale), complications, and treatment needs were assessed every 15 min for 2 h post-SA.

RESULTS

Participants had a mean age of 28.6 ± 5.8 years. Higher BMI was significantly associated with reduced shivering incidence from 30 min onward across multiple time points (P < 0.00833, Bonferroni-adjusted). At 30 min post-SA, obese and overweight women exhibited lower shivering rates than those with normal BMI (P < 0.001). After 60 min, severe shivering (grades 3-4) occurred in > 55% of normal-BMI women versus 15.8% of obese women (P < 0.001). Complications were less frequent in obese and overweight groups (P < 0.001), with 43% and 50% requiring no treatment, respectively, compared to 6.8% in the normal-BMI group (P < 0.001). Adjusted odds ratios confirmed a protective effect of higher BMI especially beyond 30 min post-intervention for postoperative shivering (e.g., obese: aOR = 0.13, 95% CI: 0.03-0.51, P = 0.003 at 30 min).

CONCLUSION

Elevated third-trimester BMI is linked to reduced POS incidence, severity, and complications, suggesting a protective role. Clinicians should prioritize shivering prevention strategies for women with normal BMI during C/S.