Table 6. Cesarean section and the odds of stillbirth, miscarriage, or ectopic pregnancy—a multinomial logistic regression analysis.
| Outcome by Mode of Deliverya | Crude Model OR (95% CI) | Adjusted OR (95% CI) | ||
| Model 1b | Model 2c | Model 3d | ||
| Stillbirth ( n = 1,518 events) | ||||
| Spontaneous vaginal (n = 1,074) | Ref | Ref | Ref | Ref |
| Operative vaginal (n = 123) | 0.93 (0.77, 1.12) | 0.98 (0.81, 1.18) | 0.96 (0.79, 1.17) | 0.99 (0.81, 1.20) |
| All cesarean sections (n = 321) | 1.54 (1.36, 1.74) | 1.50 (1.32, 1.71) | 1.40 (1.23, 1.60) | 1.32 (1.16, 1.51) |
| Emergency cesarean (n = 231) | 1.50 (1.30, 1.73) | 1.48 (1.28, 1.71) | 1.39 (1.20, 1.61) | 1.32 (1.13, 1.53) |
| Elective cesarean* (n = 90) | 1.64 (1.32, 2.04) | 1.57 (1.26, 1.96) | 1.43 (1.15, 1.79) | 1.34 (1.07, 1.68) |
| Miscarriage ( n = 68,985 events) | ||||
| Spontaneous vaginal (n = 50,363) | Ref | Ref | Ref | Ref |
| Operative vaginal (n = 6,728) | 1.09 (1.06, 1.12) | 1.03 (1.00, 1.06) | 1.03 (1.00, 1.06) | 1.04 (1.01, 1.07) |
| All cesarean sections (n = 11,894) | 1.21 (1.19, 1.24) | 1.15 (1.12, 1.17) | 1.13 (1.11, 1.16) | 1.12 (1.09, 1.14) |
| Emergency cesarean (n = 8,565) | 1.19 (1.16, 1.22) | 1.13 (1.11, 1.16) | 1.12 (1.09, 1.15) | 1.11 (1.08, 1.14) |
| Elective cesarean (n = 3,206) | 1.28 (1.24, 1.33) | 1.19 (1.15, 1.24) | 1.17 (1.12, 1.22) | 1.14 (1.10, 1.19) |
| Maternally requested cesarean (n = 123) | 1.37 (1.13, 1.66) | 1.12 (0.92, 1.37) | 1.12 (0.92, 1.36) | 1.11 (0.91, 1.36) |
| Ectopic pregnancy ( n = 11,877 events) | ||||
| Spontaneous vaginal (n = 8,599) | Ref | Ref | Ref | Ref |
| Operative vaginal (n = 996) | 0.94 (0.88, 1.01) | 1.02 (0.95, 1.09) | 1.02 (0.96, 1.10) | 1.04 (0.97, 1.12) |
| All cesarean sections (n = 2,282) | 1.37 (1.30, 1.43) | 1.34 (1.28, 1.41) | 1.29 (1.23, 1.36) | 1.30 (1.23, 1.36) |
| Emergency cesarean (n = 1,605) | 1.31 (1.24, 1.38) | 1.29 (1.22, 1.36) | 1.25 (1.18, 1.32) | 1.26 (1.19, 1.33) |
| Elective cesarean (n = 653) | 1.53 (1.41, 1.66) | 1.50 (1.38, 1.63) | 1.42 (1.31, 1.55) | 1.39 (1.28, 1.52) |
| Maternally requested cesarean (n = 24) | 1.79 (1.19, 2.70) | 1.62 (1.05, 2.50) | 1.60 (1.04, 2.47) | 1.59 (1.03, 2.46) |
Cohort 1982–2010 (n = 832,996 women).
Number of events of the outcome of interest for each mode of delivery in parentheses. Outcome refers to a composite outcome whereby the odds of pregnancy failure (stillbirth, miscarriage, or ectopic pregnancy) were compared simultaneously using multinomial logistic regression models. The reference group was live birth (n = 514,191). Women with no recorded second pregnancy event (n = 236,425) were not included in this analysis.
Model 1: adjusted for maternal age; maternal origin; previous stillbirth, miscarriage, or ectopic pregnancy; mother's marital status; birth year; and measures of socio-economic status including mother's educational attainment and mother's and father's gross income.
Model 2: adjusted for Model 1 plus medical complications in the first live birth including delivery type (singleton versus twins or more), diabetes, gestational diabetes, placental abruption, placenta praevia, and hypertensive disorders (including eclampsia and preeclampsia).
Model 3: adjusted for Model 2 plus gestational age and birth weight.
*Where the number of events was less than ten for maternally requested cesarean, these were combined with the elective cesarean group for analyses.