Table 1 Maternal characteristics and first pregnancy outcome in relation to change in BMI between first and second pregnancy
BMI change category (number of women) | ||||||||
|---|---|---|---|---|---|---|---|---|
Maternal characteristics and/or complications during first pregnancy | <−1* | −1 to <1* | 1 to <3* | ≥3* | P value¥ | Mean change in BMI (SD) | P value | |
(n = 1637) | (n = 5586) | (n = 3740) | (n = 1777) | |||||
Age (years) | ||||||||
≤19 | 11.1 | 32.7 | 28.4 | 27.8 | P = 0.000 | 1.860 (2.961) | P = 0.000 | |
20-24 | 14.3 | 39.8 | 29.4 | 16.5 | 1.122 (2.392) | |||
25-29 | 12.8 | 47.1 | 29.8 | 10.3 | 0.790 (1.884) | |||
30-34 | 11.8 | 51.1 | 29.1 | 8.0 | 0.696 (1.726) | |||
≥35 | 13.5 | 49.3 | 29.3 | 7.9 | 0.615 (1.743) | |||
Height (cm) | ||||||||
≤159 | 12.7 | 41.9 | 30.3 | 15.1 | P = 0.015 | 1.098 (2.283) | P = 0.002 | |
160-164 | 12.6 | 44.6 | 28.8 | 14.0 | 0.992 (2.235) | |||
165-169 | 12.8 | 44.6 | 29.2 | 13.4 | 0.973 (2.136) | |||
≥170 | 13.8 | 45.9 | 28.6 | 11.7 | 0.870 (2.101) | |||
Adjusted BMI (kg/m2) | ||||||||
≤18.5 | 2.6 | 47.2 | 37.9 | 12.3 | P = 0.000 | 1.396 (1.757) | P = 0.000 | |
18.6-24.9 | 9.8 | 49.7 | 29.7 | 10.8 | 0.920 (1.853) | |||
25-29.9 | 18.3 | 35.5 | 29.1 | 17.1 | 1.069 (2.525) | |||
≥30 | 20.7 | 26.4 | 25.7 | 27.2 | 1.361 (3.334) | |||
Smoking habit | ||||||||
Non-smoker | 12.2 | 45.0 | 29.7 | 13.1 | P = 0.000 | 0.991 (2.161) | P = 0.267 | |
Smoker | 15.0 | 40.3 | 28.0 | 16.7 | 1.057 (2.380) | |||
Inter-delivery interval (years) | ||||||||
≤1 | 17.5 | 48.6 | 26.4 | 7.5 | P = 0.000 | 0.508 (1.854) | P = 0.000 | |
2 | 15.6 | 51.5 | 25.0 | 7.9 | 0.503 (1.823) | |||
3 | 12.3 | 46.6 | 30.2 | 10.9 | 0.871 (1.938) | |||
>3 | 9.2 | 33.0 | 33.7 | 24.1 | 1.747 (2.615) | |||
Pre-eclampsia | No | 12.8 | 44.0 | 29.4 | 13.8 | P = 0.029 | 0.999 (2.204) | P = 0.080 |
Yes | 13.7 | 40.5 | 28.0 | 17.8 | 1.160 (2.381) | |||
Gestational hypertension | No | 13.1 | 45.2 | 28.4 | 13.3 | P = 0.000 | 0.959 (2.199) | P = 0.000 |
Yes | 12.1 | 38.7 | 32.9 | 16.3 | 1.189 (2.259) | |||
Induced labour | No | 12.8 | 44.9 | 29.0 | 13.3 | P = 0.000 | 0.968 (2.170) | P = 0.001 |
Yes | 13.1 | 41.2 | 30.2 | 15.5 | 1.107 (2.317) | |||
Instrumental delivery | No | 13.0 | 44.1 | 28.3 | 14.6 | P = 0.000 | 1.017 (2.263) | P = 0.431 |
Yes | 12.4 | 43.2 | 32.0 | 12.4 | 0.982 (2.076) | |||
Elective caesarean | No | 12.8 | 43.8 | 29.4 | 14.0 | P = 0.733 | 1.011 (2.217) | P = 0.340 |
Yes | 11.9 | 46.5 | 28.1 | 13.5 | 0.905 (2.121) | |||
Emergency caesarean | No | 12.7 | 44.2 | 29.2 | 13.9 | P = 0.089 | 1.012 (2.209) | P = 0.485 |
Yes | 14.2 | 41.2 | 30.5 | 14.1 | 0.972 (2.242) | |||
Spontaneous preterm | No | 13.0 | 43.8 | 29.4 | 13.8 | P = 0.254 | 1.004 (2.223) | P = 0.614 |
Yes | 10.8 | 45.0 | 29.3 | 14.9 | 1.044 (2.080) | |||
Post-term delivery | No | 12.9 | 43.9 | 29.3 | 13.9 | P = 0.507 | 1.000 (2.211) | P = 0.180 |
Yes | 11.7 | 42.6 | 31.3 | 14.4 | 1.109 (2.245) | |||
Placental abruption | No | 12.9 | 44.0 | 29.2 | 13.9 | P = 0.005 | 1.004 (2.218) | P = 0.213 |
Yes | 10.4 | 34.4 | 40.1 | 15.1 | 1.205 (1.906) | |||
Placenta praevia | No | 12.9 | 43.9 | 29.3 | 13.9 | P = 0.701 | 1.007 (2.214) | P = 0.981 |
Yes | 4.5 | 50.0 | 31.8 | 13.7 | 1.019 (2.016) | |||
Postpartum haemorrhage | No | 12.9 | 43.9 | 29.4 | 13.8 | P = 0.247 | 0.998 (2.211) | P = 0.148 |
Yes | 12.0 | 43.0 | 29.3 | 15.7 | 1.093 (2.230) | |||
Stillbirth | No | 12.9 | 43.8 | 29.3 | 14.0 | P = 0.300 | 1.007 (2.218) | P = 0.807 |
Yes | 8.4 | 48.6 | 32.7 | 10.3 | 0.955 (1.619) | |||
Birth weight <10th C (SGA) | No | 13.0 | 43.5 | 29.6 | 13.9 | P = 0.134 | 1.014 (2.223) | P = 0.331 |
Yes | 11.8 | 46.6 | 27.6 | 14.0 | 0.953 (2.134) | |||
Birth weight >90th C LGA) | No | 12.8 | 44.1 | 29.4 | 13.7 | P = 0.014 | 0.994 (2.201) | P = 0.023 |
Yes | 13.4 | 40.4 | 29.1 | 17.1 | 1.161 (2.346) | |||
Placental weight <10th C | No | 12.9 | 43.4 | 29.4 | 14.3 | P = 0.001 | 1.023 (2.229) | P = 0.012 |
Yes | 12.1 | 48.3 | 28.8 | 10.8 | 0.855 (2.055) | |||
Placental weight >90th C | No | 12.7 | 44.5 | 29.1 | 13.7 | P = 0.001 | 0.989 (2.190) | P = 0.006 |
Yes | 13.7 | 38.8 | 31.2 | 16.3 | 1.163 (2.396) | |||