Clinical Research Directory

* Inclusion Criteria: * Age 18 to 40 years. * Singleton pregnancy with cephalic presentation and gestational age 37 to 42 weeks. * Planned vaginal delivery. * Cervical dilatation of 3 to 4 cm at epidural catheter placement. * American Society of Anesthesiologists physical status I or II. * Request for and written informed consent to epidural labor analgesia and study participation. * Gestational diabetes mellitus group: gestational diabetes mellitus diagnosed using a 75-g, 2-hour oral glucose tolerance test according to national guidance and managed with diet and exercise without insulin during labor. * Non-gestational diabetes mellitus group: negative 75-g, 2-hour oral glucose tolerance test during the same pregnancy. * Exclusion Criteria: * Pre-existing type 1 or type 2 diabetes mellitus, or gestational diabetes mellitus requiring insulin treatment. * Endocrine disorders that affect cortisol or glucose metabolism, including Cushing syndrome or adrenal insufficiency. * Severe preeclampsia or eclampsia; complete placenta previa; previous uterine scar; threatened uterine rupture; fetal growth restriction; or severe polyhydramnios or oligohydramnios. * Severe or decompensated medical disease. * Systemic corticosteroid use, with the most recent dose administered within 72 hours before labor. * Contraindication to epidural analgesia or refusal of the procedure.