Association Between Hypoglycemia During 75-g Oral Glucose Tolerance Test and Perinatal Outcomes: A Prospective Observational Study

Background: Maternal glucose levels during pregnancy influence fetal growth and perinatal outcomes. While elevated glucose concentrations have been widely studied, the clinical relevance of low glucose values detected during routine 75-g oral glucose tolerance testing (OGTT) remains uncertain. This study aimed to determine whether hypoglycemia during OGTT is associated with gestational age at delivery and perinatal outcomes such as neonatal birth weight. Methods: In this prospective observational study, 100 pregnant women undergoing routine 75-g OGTT between 24 and 28 weeks of gestation were enrolled. Women diagnosed with gestational diabetes mellitus according to contemporary international criteria were excluded. Hypoglycemia was defined as any plasma glucose value <70 mg/dL. Participants were categorized into hypoglycemia (n=30) and normoglycemia (n=70) groups. Maternal characteristics and perinatal outcomes were compared using independent sample t-test and Chi-square test. Results: Maternal age was significantly lower in the hypoglycemia group (26.3 &plusmn; 4.7 vs 28.6 &plusmn; 5 years; p=0.032), while body mass index and parity were comparable. Mean gestational age at delivery did not differ significantly (38.2 &plusmn; 2.5 vs 38.4 &plusmn; 2 weeks; p=0.700). Neonatal birth weight was significantly lower in the hypoglycemia group (2887.5 &plusmn; 579 g vs 3138 &plusmn; 529 g; p=0.047). Preterm delivery (30% vs 26%; p=0.844), NICU admission (10% vs 13%; p=0.946), and Apgar score <7 at 5 minutes (3% vs 3%; p=0.512) were similar. Conclusion: Hypoglycemia during routine 75-g OGTT was associated with lower neonatal birth weight but not with gestational age or short-term neonatal morbidity.