Table 3

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
 Stillborn0.313 (0.015 to 2.467)1.000.697 (0.091 to 4.250)2.364 (0.506 to 12.288)
Birth type
 Spontaneous vaginal1.501 (1.087 to 2.084)1.001.728 (1.253 to 2.395)2.030 (1.417 to 2.913)
 Caesarean0.603 (0.343 to 1.041)1.000.923 (0.554 to 1.534)0.518 (0.245 to 1.019)
 Instrumental vaginal0.820 (0.613 to 1.096)1.000.649 (0.486 to 0.864)0.647 (0.465 to 0.900)
Apgar score
 5 min Apgar score ≤61.369 (0.633 to 3.072)1.000.820 (0.327 to 2.003)3.242 (1.557 to 7.118)
Infant birth weight
 LBW <2500 g1.706 (0.937 to 3.212)1.001.388 (0.731 to 2.690)1.836 (0.953 to 3.598)
 Macrosomia1.241 (0.887 to 1.743)1.001.162 (0.822 to 1.647)1.472 (0.996 to 2.169)
Maternal blood loss
 Haemorrhage ≥500 mL1.180 (0.812 to 1.720)1.001.115 (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)1.001.245 (0.513 to 3.057)0.793 (0.212 to 2.452)
 Episiotomy*1.462 (0.641 to 3.455)1.002.143 (0.995 to 4.894)0.826 (0.223 to 2.531)
Obstetric complications
 GDM†0.901 (0.248 to 3.271)1.001.548 (0.510 to 5.171)3.258 (1.129 to 10.665)
 Hypertensive disorders†1.508 (0.449 to 5.819)1.001.714 (0.511 to 6.613)3.922 (1.243 to 14.760)
Labour complications
 Shoulder dystocia*0.706 (0.222 to 2.175)1.001.160 (0.409 to 3.368)0.885 (0.246 to 2.951)
 VBAC‡1.201 (0.382 to 4.163)1.000.348 (0.048 to 1.717)0.786 (0.152 to 3.448)
Neonatal outcomes
 Hypoglycaemia1.728 (0.606 to 5.605)1.001.119 (0.334 to 3.917)1.843 (0.543 to 6.519)
 Birth trauma1.321 (0.470 to 3.981)1.001.267 (0.436 to 3.882)0.759 (0.157 to 2.939)
 Respiratory distress2.359 (1.006 to 6.109)1.001.452 (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.