Table 3.
Estimated associations between prepregnancy BMI and severe maternal morbidity with mediation by comorbidity and cesarean birth.
| Risk Ratio (95% confidenceiInterval) | ||||
|---|---|---|---|---|
| Prepregnancy BMI | Unadjusted total effect | Adjusted total effect | Adjusted natural direct effect | Adjusted natural indirect effect |
| Underweight | 1.10 (1.05, 1.16) | 1.12 (1.07, 1.18) | 1.19 (1.14, 1.26) | 0.94 (0.93, 0.95) |
| Normal weight | 1.00 (Reference) | 1.00 (Reference) | 1.00 (Reference) | 1.00 (Reference) |
| Overweight | 1.04 (1.02, 1.07) | 1.02 (0.99, 1.04) | 0.91 (0.89, 0.94) | 1.09 (1.09, 1.10) |
| Obesity Class 1 | 1.08 (1.05, 1.12) | 1.04 (1.00, 1.07) | 0.86 (0.84, 0.89) | 1.16 (1.15, 1.18) |
| Obesity Class 2 | 1.20 (1.14, 1.25) | 1.14 (1.09, 1.20) | 0.88 (0.84, 0.92) | 1.27 (1.24, 1.30) |
| Obesity Class 3 | 1.39 (1.32, 1.47) | 1.28 (1.22, 1.36) | 0.89 (0.83, 0.95) | 1.39 (1.33, 1.47) |
| Risk Differences per 10,000 births (95% confidence interval) | ||||
| Prepregnancy BMI | Unadjusted total effect | Adjusted total effect | Adjusted natural direct effect | Adjusted natural indirect effect |
| Underweight | 13.8 (6.4, 21.5) | 19.0 (10.9, 27.0) | 25.8 (17.8, 33.9) | −9.5 (−11.1, −8.1) |
| Normal weight | 0.0 (Reference) | 0.0 (Reference) | 0.0 (Reference) | 0.0 (Reference) |
| Overweight | 5.3 (1.6, 8.7) | 1.5 (−2.2, 5.2) | −11.0 (−14.3, −7.7) | 11.5 (10.9, 12.2) |
| Obesity Class 1 | 10.9 (6.3, 15.1) | 4.8 (0.4, 15.1) | −17.4 (−21.9, −13.2) | 19.5 (18.0, 21.2) |
| Obesity Class 2 | 26.3 (19.4, 32.9) | 19.6 (12.5, 25.9) | −16.3 (−22.6, −9.8) | 32.4 (29.3, 36.4) |
| Obesity Class 3 | 51.8 (41.7, 61.9) | 38.9 (28.7, 48.2) | −14.5 (−23.3, −54.9) | 48.3 (41.1, 56.8) |