Table 2.
Association between interpregnancy BMI change status and outcomes of second pregnancy.
| Outcomes of second pregnancy | BMI change status between first two pregnancies | ||||||
|---|---|---|---|---|---|---|---|
| Stable | Loss | Moderate gain | Excess gain | ||||
| (-1 to < 1 kg/m2) | (> 1 kg/m2) | (1 to < 3 kg/m2) | (≥ 3 kg/m2) | ||||
| n (%) | n (%) | RR (95% CI) | n (%) | RR (95% CI) | n (%) | RR (95% CI) | |
| Offspring birth weight | |||||||
| Normal 2.5 to < 4 kg | 2341 (92.2) | 574 (89.7) | 1.00 | 1965 (92.0) | 1.00 | 839 (90.8) | 1.00 |
| Low < 2.5 kg | 163 (6.4) | 55 (8.6) | 1.36 (1.02, 1.80) | 136 (6.4) | 1.00 (0.81, 1.25) | 57 (6.2) | 0.97 (0.72, 1.31) |
| High ≥ 4 kg | 35 (1.4) | 11 (1.7) | 0.88 (0.46, 1.69) | 34 (1.6) | 1.09 (0.68, 1.74) | 28 (3.0) | 1.62 (0.97, 2.71) |
| Offspring birth size | |||||||
| AGA 10–90 percentile | 1932 (76.2) | 488 (76.2) | 1.00 | 1583 (74.1) | 1.00 | 643 (69.7) | 1.00 |
| SGA < 10 percentile | 206 (8.1) | 54 (8.4) | 1.15 (0.87, 1.52) | 161 (7.5) | 0.94 (0.78, 1.14) | 61 (6.6) | 0.84 (0.64, 1.11) |
| LGA > 90 percentile | 399 (15.7) | 98 (15.3) | 0.87 (0.72, 1.05) | 391 (18.3) | 1.16 (1.03, 1.31) | 219 (23.7) | 1.40 (1.21, 1.61) |
| Preterm delivery < 37 weeks | |||||||
| No | 2385 (93.6) | 592 (92.1) | 1.00 | 2012 (93.8) | 1.00 | 863 (93.1) | 1.00 |
| Yes | 163 (6.4) | 51 (7.9) | 1.08 (0.80, 1.45) | 134 (6.2) | 0.96 (0.78, 1.20) | 64 (6.9) | 1.07 (0.81, 1.41) |
| Gestational diabetes | |||||||
| No | 2352 (92.3) | 580 (90.2) | 1.00 | 1956 (91.1) | 1.00 | 806 (86.9) | 1.00 |
| Yes | 196 (7.7) | 63 (9.8) | 1.04 (0.81, 1.34) | 190 (8.9) | 1.25 (1.06, 1.49) | 121 (13.1) | 1.63 (1.35, 1.97) |
| Mode of delivery | |||||||
| Vaginal delivery | 1892 (76.7) | 541 (74.4) | 1.00 | 1573 (74.5) | 1.00 | 718 (74.9) | 1.00 |
| Elective caesarean | 345 (14.0) | 102 (14.0) | 1.01 (0.89, 1.15) | 301 (14.3) | 1.02 (0.95, 1.10) | 123 (12.8) | 1.04 (0.95, 1.15) |
| Emergency caesarean | 229 (9.3) | 84 (11.6) | 1.09 (0.93, 1.28) | 238 (11.3) | 1.16 (1.03, 1.31) | 118 (12.3) | 1.14 (1.00, 1.32) |
Risk ratios are adjusted for maternal age and BMI at 12-week gestation in the first pregnancy, ethnicity, interpregnancy interval and respective pregnancy outcomes in the first pregnancy. BMI stable (− 1 to < 1 kg/m2) serves as the reference group. BMI, body mass index; RR, risk ratio; CI, confidence interval; AGA, appropriate for gestational age; SGA, small-for-gestational-age; LGA, large-for-gestational-age.