Table 5.
Crude and adjusted odds ratios for complications in second pregnancy after initial miscarriage
| Complications in second ongoing pregnancy | Interpregnancy interval (months) | |||
|---|---|---|---|---|
| <6 | 12-18 | 18-24 | >24 | |
| Pre-eclampsia: | ||||
| Crude odds ratio (95% CI) | 1.04 (0.89 to 1.21) | 1.19 (0.95 to 1.49) | 1.10 (0.84 to 1.43) | 1.05 (0.87 to 1.27) |
| Adjusted* odds ratio (95% CI) | 1.18 (0.82 to 1.23) | 1.19 (0.96 to 1.49) | 1.10 (0.84 to 1.44) | 1.05 (0.87 to 1.28) |
| Placenta praevia: | ||||
| Crude odds ratio (95% CI) | 0.85 (0.61 to 1.20) | 1.08 (0.66 to 1.76) | 1.42 (0.85 to 2.37) | 1.03 (0.68 to 1.55) |
| Adjusted* odds ratio (95% CI) | 0.89 (0.63 to 1.24) | 1.06 (0.65 to 1.72) | 1.38 (0.82 to 2.30) | 0.97 (0.64 to 1.48) |
| Placental abruption: | ||||
| Crude odds ratio (95% CI) | 0.87 (0.75 to 1.02) | 1.06 (0.84 to 1.33) | 1.11 (0.85 to 1.45) | 1.08 (0.89 to 1.30) |
| Adjusted* odds ratio (95% CI) | 0.87 (0.75 to 1.02) | 1.04 (0.82 to 1.31) | 1.11 (0.85 to 1.45) | 1.10 (0.91 to 1.34) |
| Induction of labour: | ||||
| Crude odds ratio (95% CI) | 1.07 (1.00 to 1.15) | 1.04 (0.94 to 1.16) | 1.20 (1.06 to 1.36) | 1.04 (0.95 to 1.14) |
| Adjusted*† odds ratio (95% CI) | 1.08 (1.02 to 1.23) | 0.96 (0.85 to 1.09) | 1.05 (0.89 to 1.23) | 0.94 (0.82 to 1.08) |
| Caesarean delivery: | ||||
| Crude odds ratio (95% CI) | 0.91 (0.84 to 0.98) | 1.07 (0.95 to 1.20) | 0.98 (0.85 to 1.13) | 1.23 (1.12 to 1.36) |
| Adjusted*‡ odds ratio (95% CI) | 0.90 (0.83 to 0.98) | 1.08 (0.96 to 1.23) | 0.96 (0.80 to 1.16) | 1.39 (1.26 to 1.54) |
| Preterm delivery (<36 weeks): | ||||
| Crude odds ratio (95% CI) | 0.88 (0.78 to 0.99) | 1.05 (0.89 to 1.25) | 1.01 (0.82 to 1.23) | 1.34 (1.17 to 1.53) |
| Adjusted*§ odds ratio (95% CI) | 0.89 (0.81 to 0.98) | 1.07 (0.93 to 1.23) | 1.05 (0.88 to 1.24) | 1.21 (1.07 to 1.36) |
| Very preterm delivery (<32 weeks): | ||||
| Crude odds ratio (95% CI) | 0.88 (0.70 to 1.11) | 1.26 (0.91 to 1.76) | 1.17 (0.80 to 1.73) | 1.63 (1.26 to 2.10) |
| Adjusted*§ odds ratio (95% CI) | 0.92 (0.77 to 1.10) | 1.23 (0.97 to 1.58) | 1.01 (0.75 to 1.37) | 1.40 (1.11 to1.70) |
| Low birth weight (<2500 g): | ||||
| Crude odds ratio (95% CI) | 0.70 (0.61 to 0.79) | 0.86 (0.73 to 1.01) | 1.00 (0.82 to 1.22) | 1.22 (1.08 to 1.37) |
| Adjusted*¶ odds ratio (95% CI) | 0.84 (0.71 to 0.89) | 1.17 (0.93 to 1.47) | 0.92 (0.69 to 1.21) | 1.23 (1.02 to 1.48) |
Reference category was interpregnancy interval of 6-12 months.
*Adjusted for maternal age at first pregnancy, Carstairs social deprivation category, and year of first miscarriage.
†Also adjusted for pre-eclampsia and placental abruption.
‡Also adjusted for pre-eclampsia, placenta praevia, and placental abruption.
§Also adjusted for pre-eclampsia, placenta praevia, placental abruption, and induction of labour.
¶Also adjusted for gestation at delivery.