Design: A cohort study of prospectively collected data.

Setting: American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database from 2012 – 2020.

Patients or Participants: Patients with uterine fibroid undergoing MIH.

Interventions: Hysterectomy.

Measurements and Main Results: Patients who underwent MIH for uterine fibroids were classified into BMI subgroups based on the WHO classification system. Postoperative minor and major complications occurring within 30 days, defined according to the Clavien-Dindo classification, were compared across the BMI subgroups.

A total of 61,197 patients were included in the cohort. Higher BMI classes were associated with longer operative times (range 127.1-158.1 minutes, p<0.001).

The overall rate of complications ranged 6.3%-8.1% between groups, with the highest in the obesity class 3 group. There was a significant difference in the rates of minor complications between groups; however, there was no significant difference in the rates of major complications overall.

In multivariable regression analysis comparing low and high BMI groups, higher BMI was associated with increased odds for minor complications [aOR 95% CI =1.10 (1.01-1.21)]. There was no significant association between low and high BMI and major complications.

In multivariable regression analysis comparing BMI subgroups, compared to the normal BMI group, overweight, obesity class 2 and 3 were independently associated with lower odds of major complications [aOR 95% CI 0.82 (0.71-0.94), 0.77 (0.64-0.92) and 0.82 (0.67-1.00)]. BMI categories were not independently associated with any or minor complications compared to normal the normal BMI category.

Conclusion: After adjusting for confounding factors, overweight, obesity class 2 and 3 are associated with a decreased risk of major complications compared to normal BMI. Higher BMI is associated with an increased risk of minor postoperative complications compared to lower BMI.