Table 2.
Comparison of outcomes of second pregnancy among BMI stable (reference group, OR = 1), reduced and increased interpregnancy BMI.
| Outcomes of 2nd pregnancy | BMI stable | Reduced BMI | Increased BMI | ||||
|---|---|---|---|---|---|---|---|
| n = 118,924 (72.7%) | n = 9,438 (5.8%) | n = 35,126 (21.5%) | |||||
| n (%) | n (%) | Unadjusted | Adjusted | n (%) | Unadjusted OR (95% CI) | Adjusted ORa (95% CI) | |
| OR (95% CI) | OR (95% CI) | ||||||
| PE | 3,519 (3.0%) | 340 (3.6%) | 1.23 (1.09–1.37) | 1.12 (0.99–1.26) | 1,786 (5.1%) | 1.76 (1.66–1.86) | 1.66 (1.49–1.86) |
| Placenta praevia | 726 (0.6%) | 66 (0.7%) | 1.15 (0.89–1.48) | 1.22 (0.95–1.58) | 206 (0.6%) | 0.96 (0.82–1.12) | 1.09 (0.91–1.30) |
| Placental abruption | 336 (0.3%) | 35 (0.4%) | 1.31(0.93–1.86) | 1.33 (0.93–1.91) | 100 (0.3%) | 1.01 (0.81–1.26) | 0.91 (0.70–1.18) |
| IUGR | 2,607 (2.2%) | 254 (2.7%) | 1.24 (1.09–1.41) | 1.15 (1.01–1.31) | 601 (1.7%) | 0.78 (0.71–0.85) | 0.94 (0.85–1.04) |
| Preterm birth | |||||||
| <37 weeks | 3,229 (2.7%) | 297 (3.1%) | 1.16 (1.03–1.32) | 1.14 (1.01–1.30) | 1,025 (2.9%) | 0.93 (0.86–1.00) | 0.96 (0.88–1.04) |
| <34 weeks | 693 (0.6%) | 71 (0.8%) | 1.30 (1.02–1.66) | 1.33 (1.04–1.72) | 210 (0.6%) | 0.97 (0.83–1.14) | 0.99 (0.83–1.18) |
| <32 weeks | 262 (0.2%) | 27 (0.3%) | 1.30 (0.88–1.96) | 1.15 (0.75–1.75) | 89 (0.3%) | 0.87 (0.68–1.10) | 0.90 (0.68–1.18) |
| Birthweight | |||||||
| Low <2500 g | 2,700 (2.3%) | 248 (2.6%) | 1.16 (1.02–1.33) | 1.12 (0.97–1.28) | 791 (2.3%) | 0.99 (0.92–1.07) | 1.05 (0.96–1.16) |
| High ≥4000 g | 21,094 (17.7%) | 1,619 (17.2%) | 0.96 (0.91–1.02) | 0.93 (0.87–0.98) | 8,004 (22.8%) | 1.37 (1.33–1.41) | 1.06 (1.03–1.10) |
| Stillbirth | 227 (0.2%) | 20 (0.2%) | 1.11 (0.70–1.76) | 1.13 (0.70–1.81) | 88 (0.3%) | 1.31 (0.93–1.68) | 1.14 (0.85–1.53) |
| Mode of delivery | |||||||
| Instrumental | 6,029 (5.1%) | 365 (3.9%) | 0.78 (0.69–0.86) | 0.75 (0.68–0.85) | 1,746 (5.0%) | 0.97 (0.91–1.02) | 0.96 (0.90–1.03) |
| Elective CS | 8,276 (7.0%) | 825 (8.7%) | 1.29 (1.18–1.37) | 0.96 (0.88–1.05) | 3,267 (9.3%) | 0.71 (0.68–0.74) | 0.96 (0.91–1.01) |
| Emergency CS | 7,454 (6.3%) | 657 (7.0%) | 1.12 (1.04–1.22) | 1.03 (0.94–1.13) | 2,962 (8.4%) | 0.70 (0.67–0.74) | 0.97 (0.92–1.02) |
Statistically significant odds ratios (p < 0.001) are shown as bold.
aAll odds ratios are adjusted for maternal age, BMI, smoking, social class, marital status, interpregnancy interval, country of origin, year of delivery at the second pregnancy. In addition, models were adjusted for the same outcome in the previous pregnancy. Low and high birthweight was also adjusted for gestational age at delivery preterm birth was additionally adjusted for induction of labour.