Relationship between gestational weight gain and birthweight among clients enrolled in the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC), Hawaii, 2003-2005.

To investigate the relationship between gestational weight gain (GWG) and birthweight outcomes among a low-income population in Hawaii using GWG recommendations from the 2009 Institute of Medicine (IOM) guidelines. Data were analyzed for 19,130 mother-infant pairs who participated in Hawaii's Special Supplemental Nutrition Program for Women, Infants, and Children from 2003 through 2005. GWG was categorized as inadequate, adequate, or excessive on the basis of GWG charts in the guidelines. Generalized logit models assessed the relationship between mothers' GWG and their child's birthweight category (low birthweight [LBW: < 2,500 g], normal birthweight [2,500 g ≤ BW < 4,000 g], or high birthweight [HBW: ≥ 4,000 g]). Final models were stratified by prepregnancy body mass index (underweight, normal weight, overweight, or obese) and adjusted for maternal age, education, race/ethnicity, smoking status, parity, and marital status. Overall, 62% of the sample had excessive weight gain and 15% had inadequate weight gain. Women with excessive weight gain were more likely to deliver a HBW infant; this relationship was observed for women in all prepregnancy weight categories. Among women with underweight or normal weight prior to pregnancy, those with inadequate weight gain during pregnancy were more likely to deliver a LBW infant. Among the low-income population of Hawaii, women with GWG within the range recommended in the 2009 IOM guidelines had better birthweight outcomes than those with GWG outside the recommended range. Further study is needed to identify optimal GWG goals for women with an obese BMI prior to pregnancy.