Comparison Between Metformin and Glyburide in the Management of Gestational Diabetes

Primary Outcome: treatment failure is defined as the initiation of insulin due to failure of glycemic control (more than 10% of high values using 4-point glucose checks) or side effects.

Secondary Outcomes:

Maternal:

• Percentage of fasting and postprandial glucose levels within target levels after initiation of treatment
• Incidence of maternal hypoglycemia
• Reported maternal side effects
• Maternal weight gain
• Preterm delivery
• Development of pregnancy-induced hypertension
• Labor dystocia.
• Instrumental delivery and its indication (fetal compromise, delay in progress, or maternal exhaustion)
• Mode of delivery
• Incidence of third and fourth perineal tear

Fetal and neonatal:

• Fetal large for gestational age
• Intrauterine fetal death
• Newborn weight
• Gestational age at delivery
• Neonatal birth injuries
• Stillbirth and neonatal death
• Apgar score at 1 minute

Inclusion criteria

• Pregnant women over 18 years old.
• Gestational age between 24 - 28 weeks.
• New diagnosis of gestational diabetes mellitus using a 2-hour glucose tolerance test.
• Medical therapy is indicated to control blood glucose following the failure of diet and lifestyle changes to solely achieve glycemic control (A2GDM).

Exclusion criteria

Patients with pre-gestational diabetes.

• First trimester fasting blood glucose ≥105 mg/dl or HbA1c > 6.4%.
• Major fetal anomalies.
• Intrauterine growth restriction (IUGR) before 24 weeks.
• Abnormal renal or liver function.
• Contraindications to metformin or glyburide.
• Medical treatment declined by the patient.
• Direct indication to commence insulin (initial fasting blood glucose >= 7 mmol/l or 126 mg/dl or >= 6 mmol/l or 108 mg/dl with macrosomia or polyhydramnios).
• Significant medical co-morbidities requiring continuous medical treatment in pregnancy.
• Non-compliance to blood glucose self-monitoring (missing 50% or more of total readings)