Table 1

Baseline characteristics of women by tertiles of pre-pregnancy BMI

Tertiles of pre-pregnancy BMIp Value
CharacteristicsLowMiddleHigh
Number (%)675 (33.2)684 (33.7)672 (33.1)
BMI (kg/m2), median (minimum, maximum)18.6 (12.5, 20.3)22.1 (20.3, 23.9)26.7 (23.9, 47.3)<0.01*
Age (years), mean (SD)26.6 (5.6)28.6 (5.6)30.5 (5.7)<0.01†
Women's education0.03‡
 Low education (%)170 (25.2)144 (21.1)132 (19.7)
 Middle education (%)413 (61.3)415 (60.8)415 (61.9)
 High education (%)91 (13.5)124 (18.2)123 (18.4)
Women's employment status0.01‡
 Not working (%)385 (57.2)398 (58.6)428 (63.9)
 Non-formal job (%)44 (6.5)52 (7.7)57 (8.5)
 Formal job (%)244 (36.3)229 (33.7)185 (27.6)
Monthly family income0.01‡
 <IDR1 million (%)68 (10.1)63 (9.2)68 (10.1)
 IDR1–2.5 million (%)320 (47.4)308 (45.0)291 (43.3)
 IDR2.5–5 million (%)204 (30.2)216 (31.6)203 (30.2)
 More than IDR5 million (%)29 (4.3)59 (8.6)45 (6.7)
 Refused to answer (%)54 (8.0)38 (5.6)65 (9.7)
Nulliparity (%)251 (55.8)182 (36.6)132 (25.7)<0.01‡
Women's smoking status0.46‡
 Yes, sometimes (%)3 (1.1)2 (0.7)3 (1.0)
 Yes, everyday (%)4 (1.5)1 (0.3)1 (0.3)
Partner's smoking status0.62‡
 Yes, sometimes (%)42 (15.3)40 (14.0)35 (11.8)
 Yes, everyday (%)125 (45.6)136 (47.7)153 (51.5)
Total gestational weight gain (kg), mean (SD)14.3 (7.0)12.8 (6.5)10.2 (7.1)<0.01†
Gestational age at first visit (weeks), median (IQR)13.7 (17.0)12.1 (17.3)12.7 (16.8)0.27*
Gestational age at delivery (weeks), median (IQR)39.1 (2.3)39.3 (2.1)39.3 (2.3)0.10*
Preterm birth (<37 weeks gestation) (%)50 (7.4)39 (5.7)34 (5.1)0.18‡
Post-term birth (>42 weeks gestation) (%)23 (3.4)30 (4.4)32 (4.8)0.44‡
  • *Kruskal-Wallis test.

  • †ANOVA.

  • ‡χ2 test.

  • ANOVA, analysis of variance; BMI, body mass index.