(636) Success of Labor Induction in Patients with Class III Obesity

Objective: Labor induction in patients with class III obesity poses significant challenges and has been associated with higher complication rates. This study evaluates the success rate of labor induction and identifies factors influencing successful vaginal delivery in this population.

Study Design: We conducted a retrospective cohort study using US Vital Statistics Natality Birth Data from 2018 to 2022. The study included patients with class III obesity (BMI ≥ 40) who underwent labor induction. Statistical analyses included descriptive statistics and logistic regression to identify significant predictors of successful induction. Adjusted odds ratios (aOR) were calculated.

Results: Among the 1,053,085 patients with class III obesity who underwent induction of labor, the vaginal delivery was 25.1%.

Compared to White mothers, Black (aOR = 0.79, 95% CI: 0.78-0.80), Asian (aOR = 0.80, 95% CI: 0.76-0.84), and Native Hawaiian or Other Pacific Islander (aOR = 0.76, 95% CI: 0.71-0.81) mothers had lower odds of successful induction.

Increasing maternal age was associated with decreased odds of successful induction, particularly in mothers aged 40+ years (aOR = 0.54, 95% CI: 0.52-0.56).

Higher parity was associated with increased odds of success, especially at and after grand multiparity (aOR = 2.50, 95% CI: 2.40-2.60).

Induction success rates were significantly lower at gestational age less than 37 weeks compared to 37 weeks and above (aOR = 0.567, 95% CI: 0.556-0.577). The highest statistically significant success was at 40 weeks (aOR = 1.09, 95% CI: 1.081-1.095) (Figure 1); this is likely not clinically significant given a small change in predictive probability.

At any gestational age, induction success against final birthweight followed a fitted parametric curve with peak at reference group of 3000-3499g. (p < 0.001) (Figure 2).

Conclusion: The success rate of labor induction in patients with class III obesity is 25.1%. Identifying predictive factors can aid in better management and counseling. Targeted strategies are needed to improve induction success among diverse racial groups and older maternal age categories.