Association between hypoglycemia during glucose challenge and tolerance tests in pregnancy and adverse maternal and neonatal outcomes

OBJECTIVE: To evaluate the association between hypoglycemia (defined during pregnancy as blood glucose levels <60 mg/dL) during the glucose challenge test (GCT, 50 g) and the oral glucose tolerance test (OGTT, 100 g) in pregnancy, and the risk of adverse maternal and neonatal outcomes. METHODS: A multicenter retrospective cohort study. The study population included women who experienced hypoglycemia (<60 mg/dL) during glucose challenge test or Oral Glucose Tolerance Test. Women with hypoglycemia on each test were compared with those with normal values on the respective test. Univariate analyses were followed by multivariable logistic regression. RESULTS: Overall, 2.2% (2921/145 978) of women had hypoglycemia during Glucose Challenge Test, and 16.4% (3441/30 264) had at least one hypoglycemic value on Oral Glucose Tolerance Test. In multivariable analysis, hypoglycemia during GCT was independently associated with reduced odds of delivering a large-for-gestational-age neonate (adjusted odds ratio [aOR] 0.53, 95% confidence interval [CI] 0.39-0.73) but increased odds of small-for-gestational-age (SGA) neonates (aOR 1.56, 95% CI 1.24-1.97). No independent association was found between hypoglycemia on either test or overall adverse neonatal outcome after adjustment. CONCLUSION: In this large multicenter retrospective cohort, hypoglycemia during the Glucose Challenge Test was independently associated with a higher risk of Small for Gestational Age but not with an increased risk of composite neonatal outcome. These findings may provide reassurance to clinicians and patients and help avoid unnecessary interventions.