Can maternal hypoglycemia during oral glucose tolerance test predict adverse pregnancy outcomes?

To determine whether pregnant women with hypoglycemia during the 75-g oral glucose tolerance test (OGTT) are at increased risk of adverse pregnancy outcomes (APOs). A retrospective analysis was conducted on 23,576 women who underwent a 75-g OGTT at 24-28 weeks of gestation. Hypoglycemia was defined as at least one glucose value <3.9 mmol/L. Maternal characteristics and perinatal outcomes were compared between hypoglycemic and normoglycemic groups. Univariate and multivariate analyses were used to evaluate APO risks, and the dose-response relationship between hypoglycemia severity and APOs was assessed. The hypoglycemia incidence was 7.07%. Hypoglycemic women were younger (P < 0.001) and had lower body mass indexes (BMIs) (P < 0.001). Their neonates had lower birth weights, reduced rates of large for gestational age (LGA) and macrosomia (all P < 0.001), but higher rates of low birth weight (LBW) and small for gestational age (SGA) (both P < 0.01). Logistic regression showed hypoglycemia was protective against LGA and macrosomia (both P < 0.001) but detrimental to LBW and SGA (both P < 0.01). After adjusting for confounders, hypoglycemia remained significantly associated with LGA, macrosomia, and SGA (all P < 0.05). A comparative analysis of hypoglycemia severity further revealed a strong positive trend for SGA and a negative trend for LGA (both P for trend < 0.01). Hypoglycemia during 2-hour 75-g OGTT correlates with neonatal birth weight and incidences of LGA, macrosomia, and SGA. Pregnant women with OGTT-detected hypoglycemia require close monitoring to mitigate adverse perinatal outcomes.