Evaluation of Gestational Weight Gain Guidelines for Women With Normal Prepregnancy Body Mass Index

To investigate the relationship between gestational weight gain and adverse pregnancy outcomes among women with normal prepregnancy body mass index. We conducted a population-based cohort study of women with normal prepregnancy body mass index who delivered full-term singletons using Missouri birth certificate data for 1999-2001. The cohort was divided into three groups (less than recommended [less than 25 lb], n=16,852; recommended [25-35 lb], n=37,292; more than recommended [more than 35 lb], n=40,552) based on Institute of Medicine gestational weight gain guidelines. Logistic regression was used to adjust for known confounders. Compared with women gaining 25-35 lb, women gaining less than 25 lb during pregnancy had lower odds for preeclampsia (adjusted odds ratio [aOR] 0.56, 95% confidence interval [CI] 0.49-0.64), cephalopelvic disproportion (aOR 0.64, 95% CI 0.55-0.75), failed induction (aOR 0.68, 95% CI 0.59-0.78), cesarean delivery (aOR 0.82, 95% CI 0.78-0.87), and large for gestational age infants (aOR 0.40, 95% CI 0.37-0.44) and increased odds for small for gestational age infants (aOR 2.14, 95% CI 2.01-2.27). Likewise, women gaining more than 35 lb had lower odds for small for gestational age infants (aOR 0.48, 95% CI 0.45-0.50) and increased odds for preeclampsia (aOR 1.88, 95% CI 1.74-2.04), failed induction (aOR 1.51, 95% CI 1.39-1.64), cesarean delivery (aOR 1.35, 95% CI 1.29-1.40), and large for gestational age infants (aOR 2.43, 95% CI 2.30-2.56). Our study shows that adherence to the current Institute of Medicine guidelines results in lower risks for adverse pregnancy, labor, and delivery outcomes when comparing all outcomes collectively.