Adjusted ORs for outcomes during the subsequent pregnancy in relation to interpregnancy BMI change for women of all parities
| Decrease of ≥1 BMI units n=552 OR (95% CI) | No change in BMI units n=496 OR (95% CI) | Increase of 1 to <3 BMI units n=509 OR (95% CI) | Increase of ≥3 BMI units n=311 OR (95% CI) | |
|---|---|---|---|---|
| Birth status | ||||
| Stillborn | 0.313 (0.015 to 2.467) | 1.00 | 0.697 (0.091 to 4.250) | 2.364 (0.506 to 12.288) |
| Birth type | ||||
| Spontaneous vaginal | 1.501 (1.087 to 2.084) | 1.00 | 1.728 (1.253 to 2.395) | 2.030 (1.417 to 2.913) |
| Caesarean | 0.603 (0.343 to 1.041) | 1.00 | 0.923 (0.554 to 1.534) | 0.518 (0.245 to 1.019) |
| Instrumental vaginal | 0.820 (0.613 to 1.096) | 1.00 | 0.649 (0.486 to 0.864) | 0.647 (0.465 to 0.900) |
| Apgar score | ||||
| 5 min Apgar score ≤6 | 1.369 (0.633 to 3.072) | 1.00 | 0.820 (0.327 to 2.003) | 3.242 (1.557 to 7.118) |
| Infant birth weight | ||||
| LBW <2500 g | 1.706 (0.937 to 3.212) | 1.00 | 1.388 (0.731 to 2.690) | 1.836 (0.953 to 3.598) |
| Macrosomia | 1.241 (0.887 to 1.743) | 1.00 | 1.162 (0.822 to 1.647) | 1.472 (0.996 to 2.169) |
| Maternal blood loss | ||||
| Haemorrhage ≥500 mL | 1.180 (0.812 to 1.720) | 1.00 | 1.115 (0.760 to 1.640) | 1.211 (0.783 to 1.860) |
| Peristatus | ||||
| Third-degree /fourth-degree tear* | 0.997 (0.399 to 2.490) | 1.00 | 1.245 (0.513 to 3.057) | 0.793 (0.212 to 2.452) |
| Episiotomy* | 1.462 (0.641 to 3.455) | 1.00 | 2.143 (0.995 to 4.894) | 0.826 (0.223 to 2.531) |
| Obstetric complications | ||||
| GDM† | 0.901 (0.248 to 3.271) | 1.00 | 1.548 (0.510 to 5.171) | 3.258 (1.129 to 10.665) |
| Hypertensive disorders† | 1.508 (0.449 to 5.819) | 1.00 | 1.714 (0.511 to 6.613) | 3.922 (1.243 to 14.760) |
| Labour complications | ||||
| Shoulder dystocia* | 0.706 (0.222 to 2.175) | 1.00 | 1.160 (0.409 to 3.368) | 0.885 (0.246 to 2.951) |
| VBAC‡ | 1.201 (0.382 to 4.163) | 1.00 | 0.348 (0.048 to 1.717) | 0.786 (0.152 to 3.448) |
| Neonatal outcomes | ||||
| Hypoglycaemia | 1.728 (0.606 to 5.605) | 1.00 | 1.119 (0.334 to 3.917) | 1.843 (0.543 to 6.519) |
| Birth trauma | 1.321 (0.470 to 3.981) | 1.00 | 1.267 (0.436 to 3.882) | 0.759 (0.157 to 2.939) |
| Respiratory distress | 2.359 (1.006 to 6.109) | 1.00 | 1.452 (0.550 to 4.051) | 1.831 (0.644 to 5.320) |
Significant results are shown in bold typeface.
The reference group is no change in BMI units.
ORs and 95% CIs from logistic models adjusted for baseline BMI, interpregnancy interval, maternal age, country of birth, parity and smoking.
*Women who had a caesarean for the second pregnancy excluded (n=1482).
†Women who had GDM and hypertension in the first pregnancy excluded (n=1802).
‡Women who had a caesarean for the first pregnancy only (n=367).
BMI, body mass index; GDM, gestational diabetes mellitus; LBW, low birth weight; VBAC, vaginal birth after caesarean.