Table 4.
Reproductive and perinatal outcomes in women who had induced abortion, live birth or miscarriage following a live birth in the first pregnancy
| Outcome of second pregnancy | Induced abortion versus live birth | Induced abortion versus miscarriage | |||
| Induced abortion | Live birth | Miscarriage | |||
| Outcome of third pregnancy | N=30 527 | N=125 855 | N=22 404 | Crude and adjusted (Adj.) RR (99% CI)* | |
| Live birth | 18 562 (60.8) | 85 014 (67.5) | 17 745 (79.2) | Crude 0.90 (0.89 to 0.91) | Crude 0.77 (0.76 to 0.78) |
| Adj. 0.88 (0.87 to 0.89) | Adj. 0.77 (0.76 to 0.78) | ||||
| Stillbirth | 84 (0.3) | 426 (0.3) | 69 (0.3) | Crude 0.81 (0.60 to 1.11) | Crude 0.89 (0.59 to 1.36) |
| Adj. 0.76 (0.55 to 1.06) | Adj. 0.86 (0.54 to 1.37) | ||||
| Miscarriage | 2005 (6.6) | 8778 (7.0) | 2869 (12.8) | Crude 0.94 (0.89 to 1.00) | Crude 0.51 (0.48 to 0.55) |
| Adj. 0.93 (0.88 to 1.00) | Adj. 0.67 (0.62 to 0.72) | ||||
| Ectopic pregnancy | 339 (1.1) | 1064 (0.9) | 181 (0.8) | Crude 1.31 (1.12 to 1.54) | Crude 1.38 (1.09 to 1.74) |
| Adj. 1.31 (1.11 to 1.56) | Adj. 1.16 (0.90 to 1.50) | ||||
| Induced abortion | 9537 (31.2) | 30 573 (24.3) | 1540 (6.9) | Crude 1.29 (1.25 to 1.32) | Crude 4.55 (4.25 to 4.86) |
| Adj. 1.33 (1.30 to 1.37) | Adj. 4.37 (4.06 to 4.70) | ||||
| Outcomes in ongoing pregnancies | N=18 646 | N=85 440 | N=17 814 | Crude and adjusted (Adj.) RR (99% CI)† | |
| Pre-eclampsia | 144 (0.8) | 567 (0.7) | 165 (0.9) | Crude 1.16 (0.92 to 1.48) | Crude 0.83 (0.62 to 1.12) |
| Adj. 1.40 (1.10 to 1.79) | Adj. 0.91 (0.66 to 1.27) | ||||
| Placenta praevia | 183 (1.0) | 473 (0.6) | 133 (0.8) | Crude 1.77 (1.42 to 2.22) | Crude 1.32 (0.98 to 1.76) |
| Adj. 1.78 (1.40 to 2.25) | Adj. 1.34 (0.97 to 1.84) | ||||
| Abruptio placenta | 91 (0.5) | 325 (0.4) | 66 (0.4) | Crude 1.28 (0.95 to 1.74) | Crude 1.32 (0.87 to 2.00) |
| Adj. 1.28 (0.93 to 1.77) | Adj. 1.32 (0.83 to 2.10) | ||||
| Induction of labour‡ | 4298 (23.1) | 18 239 (21.4) | 3968 (22.3) | Crude 1.08 (1.04 to 1.12) | Crude 1.03 (0.98 to 1.09) |
| Adj. 1.11 (1.07 to 1.16) | Adj. 1.01 (0.96 to 1.07) | ||||
| Low birth weight <2500§ | 1086 (5.8) | 3905 (4.6) | 784 (4.4) | Crude 1.28 (1.17 to 1.39) | Crude 1.32 (1.17 to 1.49) |
| Adj. 1.36 (1.21 to 1.51) | Adj. 1.04 (0.90 to 1.21) | ||||
| Outcomes in spontaneous births | N=12 868 | N=59 220 | N=12 056 | ||
| Spontaneous preterm birth <37 weeks | 859 (6.7) | 3035 (5.1) | 644 (5.3) | Crude 1.30 (1.18 to 1.43) | Crude 1.25 (1.10 to 1.42) |
| Adj. 1.27 (1.14 to 1.40) | Adj. 1.14 (0.99 to 1.32) | ||||
| Spontaneous very preterm birth <32 weeks | 162 (1.3) | 495 (0.8) | 104 (0.9) | Crude 1.51 (1.19 to 1.90) | Crude 1.46 (1.06 to 2.01) |
| Adj. 1.44 (1.12 to 1.84) | Adj. 1.35 (0.93 to 1.96) | ||||
Values are n (%) unless otherwise specified. Statistically significant relative risks are shown in bold.
*
Adjusted for age, year of delivery, Carstairs at second pregnancy and interpregnancy interval.
†
Adjusted for maternal age, year of pregnancy, Carstairs category at second pregnancy and interpregnancy interval.
‡
Further adjusted for pre-eclampsia, placenta praevia and abruptio placenta.
§
Low birth weight also adjusted for gestational age.