Objective This study aimed to determine if one abnormal value of four on the diagnostic 3-hour oral glucose tolerance test (OGTT) is associated with adverse perinatal outcomes in obese women.
Study Design This is a secondary analysis of a prospective study of nulliparous women in eight geographic regions. Women with body mass index <30 kg/m2 and pregestational diabetes mellitus (GDM) were excluded. Four groups were compared: (1) normal 50-g 1-hour glucose screen, (2) elevated 1-hour glucose screen with normal 100-g 3-hour diagnostic OGTT, (3) elevated 1-hour glucose screen and one of four abnormal values on 3-hour OGTT, and (4) GDM. Using multivariable logistic regression adjusting for covariates, the women in the groups with dysglycemia were compared with those in the normal screen group for maternal and neonatal outcomes.
Results Among 1,713 obese women, 1,418 (82.8%) had a normal 1-hour glucose screen, 125 (7.3%) had a normal 3-hour diagnostic OGTT, 72 (4.2%) had one abnormal value on their diagnostic OGTT, and 98 (5.7%) were diagnosed with GDM. The one abnormal value group had increased risk of large for gestational age (LGA) neonates (adjusted odds ratio [aOR] = 2.24, 95% confidence interval [CI]: 1.31–3.82), cesarean delivery (aOR = 2.19, 95% CI: 1.34–3.58), and hypertensive disorders of pregnancy (aOR = 2.19, 95% CI: 1.32–3.63) compared with normal screens. The one abnormal value group also had an increased risk of preterm birth <37 weeks (aOR = 2.63, 95% CI: 1.43–4.84), neonatal respiratory support (aOR = 2.38, 95% CI: 1.23–4.60), and neonatal hyperbilirubinemia (aOR = 2.00, 95% CI: 1.08–3.71). There was no association between one abnormal value with shoulder dystocia and neonatal hypoglycemia.
Conclusion For obese women, one abnormal value on the 3-hour OGTT confers increased perinatal adverse outcomes. These women should be studied further to determine if nutrition counseling and closer fetal monitoring improve outcomes even in the absence of a diagnosis of GDM.
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