Assessing the impact of delivery method on severe maternal morbidity among individuals with inflammatory bowel disease: a population-based study

Background & aims — Individuals with inflammatory bowel disease (IBD) may have worse obstetrical outcomes than those without IBD. We assessed the odds of severe maternal morbidity (SMM) among individuals with IBD compared to those without by IBD subtype (Crohn’s disease [CD] or ulcerative colitis [UC]), and whether the method of delivery impacted the odds of SMM.

Methods — We conducted a retrospective, population-based matched cohort study of females aged 15-49 years in Ontario, Canada from 2003 to 2019 delivering at 20+ weeks’ gestation. The primary outcome was SMM occurring between 20 weeks’ gestation up to 42-days postpartum. We identified deliveries among individuals with IBD using health administrative data and matched them 1:5 to deliveries among individuals without IBD from the general population of Ontario residents. Multivariable regression models estimated the adjusted odds ratio (OR) of SMM in antepartum and postpartum periods. We tested for interactions between IBD status and delivery method.

Results — 6833 deliveries in individuals with IBD (3800 CD and 3033 UC) were matched to 34 165 non-IBD deliveries. More individuals with IBD underwent C-section (36.5% vs 30.9%, standardized mean difference, SMD: 0.12). Compared with individuals without IBD, those with IBD had higher odds of antepartum SMM (OR: 3.5, 95% CI: 2.1-5.8) and postpartum SMM (OR: 1.3, 95% CI: 1.0-1.5). The odds of SMM among individuals with and without IBD was not modified by method of delivery (interaction term P = .17).

Conclusions — Individuals with IBD were at increased risk of SMM, independent of delivery method. Pregnancy care should focus on optimization of other IBD-related risk factors.