Evaluation of gestational weight gain guidelines for women with normal prepregnancy body mass index.

Objective: To investigate the relationship between gestational weight gain and adverse pregnancy outcomes among women with normal prepregnancy body mass index.

Methods: 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.

Results: 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).

Conclusion: 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.