Gestational weight gain and gestational diabetes mellitus: perinatal outcomes.

OBJECTIVE: To examine the association between gestational weight gain and perinatal outcome in women with gestational diabetes mellitus (GDM). METHODS: This is a retrospective cohort study of women with nonanomalous singleton pregnancies with GDM enrolled in the Sweet Success California Diabetes and Pregnancy Program between 2001 and 2004. Gestational weight gain, calculated from prepregnancy weight and weight at last prenatal Sweet Success visit, was subgrouped into below, within, and above the Institute of Medicine (IOM) weight-gain guidelines. Perinatal outcomes were examined using chi2 test and multivariable regression analysis with 15-35-lb weight gain as the reference group. RESULTS: There were 31,074 women meeting study criteria. Compared with women with gestational weight gain within the IOM guidelines, women who gained above the guidelines had higher odds of having large for gestational age neonates (adjusted odds ratio [aOR] 1.72, 95% confidence interval [CI] 1.53-1.93, number needed to harm 10), preterm delivery (aOR 1.30, 95% CI 1.14-1.48, number needed to harm 32), and primary cesarean delivery (aOR 1.52, 95% CI 1.26-1.83, number needed to harm 10). Women who gained below the guidelines had higher odds of having small for gestational age neonates (aOR 1.39, 95% CI 1.01-1.90) and maintaining diet-controlled GDM (aOR 1.47, 95% CI 1.34-1.63) and lower odds of having large for gestational age neonates (aOR 0.60, 95% CI 0.52-0.67). CONCLUSION: Women diagnosed with GDM who had gestational weight gain above the IOM guidelines have higher risk of undesirable outcomes, including preterm delivery, having macrosomic neonates, and cesarean delivery. Women who gained below guidelines are more likely to remain on diet control but have small for gestational age neonates. LEVEL OF EVIDENCE: II.

Screening or diagnostic: markedly elevated glucose loading test and perinatal outcomes.

OBJECTIVE: To determine the diagnostic value of markedly elevated 50-g glucose loading test results (>or=200 mg/dL) and associated perinatal outcomes. METHOD: This was a retrospective cohort study of 14 771 pregnancies screened for gestational diabetes mellitus (GDM) between 1988 and 2001. The positive predictive value of the 50-g oral glucose loading test (GLT) results as measured by plasma glucose value was examined. Perinatal outcomes were assessed for women with GLT results >or=200 mg/dL compared to GLT <200 mg/dL, stratified by the diagnosis of GDM. Statistical comparisons were made using the Chi-square test and Student's t-test and potential confounding factors were controlled for using multivariable logistic regression analyses. A p value <0.05 and 95% confidence intervals were used to indicate statistical significance. RESULTS: The positive predictive values for a GDM diagnosis were 62% for GLT results between 180 and 189 mg/dL, 79% for those between 200 and 209 mg/dL, and 100% for GLT results >or=230 mg/dL. Compared to women with a GLT result <200 mg/dL, among women not diagnosed with GDM but with a GLT >or=200 mg/dL the adjusted odds ratio (aOR) for cesarean delivery was 4.18 (95% confidence intervals, 1.15-15.2). These women also had higher aORs for preterm delivery <32 weeks (aOR = 8.05 (1.02-63.6)), shoulder dystocia (aOR = 15.14 (1.64-140)), and their neonates were more likely to have a 5-minute Apgar score <7 (aOR = 6.41 (1.23-33.3)). For women diagnosed with GDM and with a GLT >or=200 mg/dL, the aOR for cesarean delivery was also elevated compared to those with a GLT <200 mg/dL (aOR = 2.24 (1.19-4.21)). CONCLUSION: A GLT value of >or=200 mg/dL is not absolutely diagnostic for gestational diabetes but is associated with unfavorable perinatal outcomes.