Patterns of weight gain during the first half of pregnancy and risk of large newborns in women with insulin-dependent diabetes mellitus.

OBJECTIVE: To identify patterns of gestational weight gain (pGWG) trajectories in the first 20 weeks of gestation and to determine the association of these patterns with the delivery of large-for-gestational-age (LGA) infants among women with insulin-dependent diabetes mellitus (IDDM). STUDY DESIGN: Analysis of data collected prospectively in a Diabetes in Pregnancy Program Project Grant 7/1978 to 6/1993. Sparse functional principal components analysis was used to identify clusters defining phenotypes of women with similar pGWG in the first 20 weeks of gestation. Generalized estimating equations (GEEs) were used to estimate the association between maternal phenotype according to pGWG and odds of LGA (> 90th percentile) at birth, adjusting for predefined covariates and confounders; age, age of diagnosis of diabetes, race, parity, chronic hypertension, nephropathy, retinopathy, body mass index (BMI), and glycohemoglobin A1. GEEs were also used to examine the association of LGA and total weight gain over the first 20 weeks of gestation. RESULTS: A total of 349 pregnancies were included in this analysis. Three phenotypes of pGWG were identified and classified as high pGWG (highest 25% of trajectories; n = 84), moderate pGWG (middle 50% of trajectories; n = 176), and low pGWG (lowest 25% of trajectories; n = 89). Phenotype was positively associated with prepregnancy BMI (p < 0.0001) and total GWG (p < 0.0001). Women with high pGWG (adjusted odds ratio [aOR] = 3.54; 95% confidence interval [CI], 1.31-9.51) and moderate pGWG (aOR = 2.41; 95% CI, 1.09-5.35) had significantly increased odds of delivering an LGA infant, compared to women in the low pGWG. However, total weight gain over the first 20 weeks of gestation was not significantly associated with delivery of an LGA infant. CONCLUSIONS: Moderate or high pGWG during the first 20 weeks of gestation was associated with increased odds of delivering an LGA infant. Future studies should consider pGWG in early pregnancy rather than overall early GWG to strategize interventions when examining the likelihood of delivering an LGA infant.