Abstract
The purpose of this study was to determine the influence of maternal prepregnancy body mass index on preterm delivery (PTD), controlling for health and lifestyle variables. Prospective data were from 83,544 pregnancies in the Norwegian Mother and Child Cohort Study.
PTD was divided into early PTD (22 + 0 to 31 + 6 weeks' gestation) and late PTD (32 + 0 to 36 + 6 weeks' gestation). The overall prevalence of PTD was 5.1%.
Increased body mass index was associated with an increased risk of PTD; adjusted odds ratio (aOR) ranged from 1.11 (95% confidence interval [CI], 1.03-1.20) for preobesity to 2.00 (95% CI, 1.48-2.71) for grade-III obesity in the group that included all PTD subgroups. Grade-III obese women had an increased risk of both early and late PTD: aOR, 3.24 (95% CI, 1.71-6.14) and 1.81 (95% CI, 1.29-2.54), respectively.
Prepregnancy maternal overweight increases the risk of both early and late PTD.