Table 1

Characteristics of the study population

Total
(n=4800)
Subcohort (n=1059)Without adverse birth outcomes*
(n=545)
With adverse birth outcomes
(n=514)
Age (SD)26.4 (3.6)26.5 (3.7)26.2 (3.6)26.7 (3.9)
Prepregnancy BMI (SD)20.9 (2.9)21.2 (3.1)20.9 (3.0)21.5 (3.2)
Weight gain (SD)14.5 (5.0)14.5 (5.2)14.5 (4.9)14.4 (5.4)
Gestation duration (SD)39.2 (1.3)38.6 (1.9)39.5 (0.9)37.8 (2.3)
Delivery mode
 Vaginal54.9%49.5%59.1%39.4%
 Caesarean45.1%50.5%40.9%60.6%
Pregnancy complications
 Gestational diabetes mellitus3.0%8.3%7.6%9.1%
 Gestation-induced hypertension1.9%2.1%0.6%3.8%
 Anaemia in pregnancy45.0%39.2%39.6%38.8%
Adverse birth outcomes
 Preterm5.5%22.3%046.7%
 Low birth weight3.1%12.9026.7%
 Macrosomia4.9%20.4%042.0%
Gravidity
 135.0%36.6%40.9%32.2%
 228.4%28.5%27.2%29.8%
 319.0%17.3%16.3%18.3%
 411.2%10.2%9.4%10.9%
 >46.4%7.5%6.3%8.8%
Parity
 057.5%60.7%61.4%60.0%
 141.3%38.5%38.3%38.8%
 ≥21.2%0.76%0.4%1.2%
  • *Adverse birth outcomes of interest in this study are preterm delivery, low birth weight and macrosomia.

  • BMI, body mass index.