Table 2

Reproductive and perinatal outcomes following induced abortion, miscarriage or live birth in first pregnancy

Outcome in first pregnancyCrude and adjusted (Adj.) RR (99% CI)*
Induced abortionLive birthMiscarriageInduced abortion versus live birthInduced abortion versus miscarriage
Outcome of second pregnancyN=120 033N=457 477N=47 355
 Live birth67 336 (56.1)355 674 (77.7)36 479 (77.0)Crude 0.72 (0.71 to 0.73)Crude 0.72 (0.72 to 0.73)
Adj. 0.74 (0.73 to 0.74)Adj. 0.69 (0.69 to 0.70)
 Stillbirth409 (0.34)1406 (0.31)247 (0.52)Crude 1.11 (0.96 to 1.28)Crude 0.65 (0.53 to 0.80)
Adj. 1.06 (0.91 to 1.24)Adj. 0.58 (0.46 to 0.74)
 Miscarriage7965 (6.6)30 669 (6.7)6197 (13.1)Crude 0.99 (0.96 to 1.02)Crude 0.51 (0.49 to 0.53)
Adj. 1.05(1.01 to 1.08) Adj. 0.56 (0.54 to 0.59)
 Ectopic pregnancy1115 (0.9)2939 (0.6)499 (1.1)Crude 1.45 (1.32 to 1.58)Crude 0.88 (0.77 to 1.01)
Adj. 1.36 (1.23 to 1.50) Adj. 0.83 (0.71 to 0.97)
 Induced abortion43 208 (36.0)66 789 (14.6)3933 (8.3)Crude 2.47 (2.43 to 2.50)Crude 4.33 (4.16 to 4.51)
Adj. 2.30 (2.27 to 2.33) Adj. 4.64 (4.44 to 4.85)
Outcome in first pregnancyCrude and adjusted (Adj.) RR (99% CI)*
Induced abortionLive birthMiscarriagePrimigravidaInduced abortion versus live birthInduced abortion versus miscarriageInduced abortion versus primigravida
Outcomes in ongoing pregnanciesN=67 745N=357 080N=36 726N=457 477
 Pre-eclampsia1583 (2.3)2982 (0.8)922 (2.5)8649 (1.9)Crude 2.80 (2.58 to 3.03)Crude 0.93 (0.84 to 1.03)Crude 1.24 (1.15 to 1.32)
Adj. 2.42 (2.21 to 2.65) Adj. 0.83 (0.73 to 0.94) Adj. 1.26 (1.17 to 1.35)
 Placenta praevia385 (0.6)1919 (0.5)289 (0.8)2042 (0.5)Crude 1.06 (0.92 to 1.22)Crude 0.72 (0.59 to 0.88)Crude 1.27 (1.10 to 1.47)
Adj. 1.09 (0.93 to 1.28)Adj. 0.79 (0.62 to 1.01)Adj. 1.05 (0.91 to 1.22)
 Abruptio placenta339 (0.5)1197 (0.3)173 (0.5)1770 (0.4)Crude 1.49 (1.27 to 1.75)Crude 1.06 (0.84 to 1.35)Crude 1.30 (1.11 to 1.51)
Adj. 1.49 (1.25 to 1.77) Adj. 1.00 (0.76 to 1.32)Adj. 1.28 (1.10 to 1.50)
 Induction of labour 18 044 (26.6)69 482 (19.5)10 347 (28.2)120 080 (26.3)Crude 1.37 (1.34 to 1.39)Crude 0.95 (0.92 to 0.97)Crude 1.01 (1.00 to 1.03)
Adj. 1.33 (1.30 to 1.35) Adj. 0.98 (0.95 to 1.01)Adj. 1.00 (0.99 to 1.02)
 Low birth weight <2500 g 5385 (8.0)16 309 (4.6)3101 (8.5)28 735 (6.3)Crude 1.74 (1.67 to 1.81)Crude 0.94 (0.89 to 1.00)Crude 1.27 (1.22 to 1.31)
Adj. 1.24 (1.17 to 1.31) Adj. 0.96 (0.90 to 1.03)Adj. 1.08 (1.04 to 1.13)
Outcomes in spontaneous birthsN=45 656N=255 220N=23 751N=318 217
 Spontaneous preterm birth <37 weeks4224 (9.3)13 453 (5.3)2376 (10.0)21 891 (6.9)Crude 1.76 (1.68 to 1.83)Crude 0.92 (0.86 to 0.97)Crude 1.35 (1.29 to 1.40)
Adj. 1.66 (1.58 to 1.74) Adj. 0.85 (0.79 to 0.91) Adj. 1.37 (1.32 to 1.42)
 Spontaneous very preterm birth <32 weeks878 (1.9)2157 (0.9)513 (2.2)4051 (1.3)Crude 2.28 (2.05 to 2.52)Crude 0.89 (0.77 to 1.03)Crude 1.51 (1.37 to 1.66)
Adj. 2.20 (1.96 to 2.47) Adj. 0.83 (0.70 to 0.99) Adj. 1.57 (1.43 to 1.72)
  • Values are n (%) unless otherwise specified. Statistically significant relative risks are shown as bold.

  • * Adjusted for maternal age, year of delivery, Carstairs at first pregnancy and interpregnancy interval.

  • Further adjusted for pre-eclampsia, placenta praevia and abruptio placenta.

  • Low birth weight also adjusted for gestational age.