Table 4

Adjusted ORs for outcomes during the subsequent pregnancy in relation to interpregnancy BMI change for women from parity 0 to 1

Decrease of ≥1 BMI units
(n=329)
OR (95% CI)
No change in BMI units
(n=309)
OR (95% CI)
Increase of 1 to <3 BMI units
(n=328)
OR (95% CI)
Increase of ≥3 BMI units
(n=189)
OR (95% CI)
Birth status
 Stillborn0.973 (0.038 to 24.759)1.002.066 (0.196 to 44.776)3.955 (0.372 to 86.065)
Birth type
 Spontaneous vaginal0.944 (0.654 to 1.362)1.000.671 (0.470 to 0.954)0.727 (0.480 to 1.104)
 Caesarean1.344 (0.890 to 2.040)1.001.534 (1.026 to 2.310)1.806 (1.139 to 2.862)
 Instrumental vaginal0.580 (0.297 to 1.104)1.001.107 (0.631 to 1.954)0.582 (0.250 to 1.240)
Apgar score
 5 min Apgar score ≤62.005 (0.700 to 6.526)1.001.575 (0.518 to 5.282)5.197 (1.932 to 16.434)
Infant birth weight
 Macrosomia1.202 (0.779 to 1.864)1.001.138 (0.734 to 1.770)1.537 (0.939 to 2.505)
 LBW <2500 g2.553 (1.088 to 6.695)1.000.863 (0.288 to 2.581)1.734 (0.621 to 5.027)
Maternal blood loss
 Haemorrhage ≥500 mL1.078 (0.670 to 1.738)1.001.043 (0.648 to 1.680)1.183 (0.682 to 2.026)
Peristatus
 Third-degree/fourth-degree tear*0.922 (0.290 to 2.854)1.001.560 (0.582 to 4.411)0.848 (0.178 to 3.171)
 Episiotomy*1.074 (0.293 to 3.934)1.003.571 (1.342 to 11.255)0.379 (0.020 to 2.415)
Obstetric complications
 GDM†1.224 (0.263 to 6.357)1.002.267 (0.48 to 16.006)4.211 (0.881 to 29.957)
 Hypertensive disorders†4.626 (0.737 to 89.051)1.003.696 (0.54 to 72.696)9.642 (1.517 to 186.621)
Labour complications
 Shoulder dystocia*0.768 (0.207 to 2.843)1.001.160 (0.408 to 3.369)0.849 (0.235 to 2.839)
 VBAC‡1.605 (0.476 to 6.210)1.000.256 (0.013 to 1.841)0.906 (0.117 to 5.127)
Neonatal outcomes
 Hypoglycaemia1.197 (0.312 to 4.901)1.000.976 (0.228 to 4.184)1.790 (0.414 to 7.740)
 Birth trauma1.472 (0.482 to 4.944)1.001.108 (0.329 to 3.892)0.297 (0.015 to 1.886)
 Respiratory distress2.618 (0.877 to 9.584)1.001.215 (0.317 to 4.971)1.196 (0.231 to 5.545)
  • 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 and smoking.

  • *Women who had a caesarean excluded (n=856).

  • †Women who had gestational diabetes and hypertension in the first pregnancy excluded (n=924).

  • ‡Women who had a caesarean for the first pregnancy only (n=231).

  • BMI, body mass index; GDM, gestational diabetes mellitus; LBW, low birth weight; VBAC, vaginal birth after caesarean.