Objective: To evaluate the effects of high pre-pregnancy body mass index (BMI) on the risk of poor obstetric outcomes among
Asian women using BMI criteria by Regional Office for the Western Pacific Region of WHO (WPRO).
Material and Method: The present study was a retrospective cohort. Subjects of live birth singletons who had full term
delivered at four tertiary care centers, teaching university hospitals between January and December 2012 were enrolled. All pregnant women with pre-pregnancy BMI 18.5 kg/m2 or over were recruited and categorized into two groups, normal BMI
and high BMI. Level of BMI at 18.5-22.9 kg/m2 was defined normal BMI, and level at or over than 23 kg/m2 was defined as
high BMI, respectively. The association between high pre-pregnancy BMI and poor adverse pregnancy outcomes were
evaluated.
Results: Two thousands seven hundred and thirty-three pregnant women were recruited. Normal and high pre-pregnancy
BMI women were 1,840 and 893, respectively. The average age was 27.81+5.67 and 29.48+13.03 years old respectively.
Most of subject were primigravida. Mean BMI of normal group and high BMI group were 20.27+1.42 and 26.66+3.45 kg/
m2, respectively. In multivariate analysis, high pre-pregnancy BMI pregnant women have significantly higher adjusted risk
ratio for gestational diabetes mellitus and preeclampsia, induction of labor, prolong second stage of labor, including,
caesarean delivery or obstetrics procedures (RR 1.54, 95% CI 1.30-1.84, RR 1.17, 95% CI 1.12-1.23, RR 1.41, 95% CI 1.04-
1.90, RR 1.28, 95% CI 1.11-1.48 and RR 1.17, 95% CI 1.05-1.27, respectively). In addition, the adjusted risk ratio of
postpartum hemorrhage and neonatal macrosomia were significantly increased (RR 1.86, 95% CI 1.01-3.43 and RR 1.46, 95% CI 1.28-1.65, respectively).
Conclusion: This evidence strongly suggested that high pre-pregnancy BMI using WPRO criteria increased the risk of pregnancy complications and adverse pregnancy outcomes. This study was one of the largest studies among Asian populations.

Keywords: Body mass index, Pregnancy, Obese