What is the recommended treatment approach for a pregnant woman of Indian descent with gestational diabetes mellitus (GDM)?

Management of Gestational Diabetes Mellitus: Indian Guidelines

All pregnant women in India should be screened for GDM using a single-step 75g oral glucose tolerance test at 24-28 weeks of gestation, with treatment starting with lifestyle modifications and progressing to insulin if glycemic targets are not met. 1

Screening Approach for Indian Women

• Universal screening is essential for all pregnant Indian women due to the high prevalence of GDM in this population 1
• The Diabetes In Pregnancy Study group India (DIPSI) recommends a simplified one-step procedure: administer 75g oral glucose load when the pregnant woman arrives fasting at the antenatal clinic, then measure venous plasma glucose at 2 hours 1
• This single-step approach is specifically designed to be simple, economical, and feasible for the Indian healthcare environment 1
• Screening should occur between 24-28 weeks of gestation 1

Glycemic Targets

• Fasting glucose <95 mg/dL (5.3 mmol/L) 2, 3, 4
• One-hour postprandial glucose <140 mg/dL (7.8 mmol/L) 2, 3, 4
• Two-hour postprandial glucose <120 mg/dL (6.7 mmol/L) 2, 3, 4

Initial Management: Lifestyle Modifications

Medical Nutrition Therapy

• All women with GDM must receive individualized medical nutrition therapy from a registered dietitian nutritionist familiar with GDM management 3
• Minimum daily requirements include:
  • 175g carbohydrates 3, 4
  • 71g protein 3, 4
  • 28g fiber 3, 4
• Carbohydrates should be distributed across three small-to-moderate meals and 2-4 snacks throughout the day to limit postprandial glucose excursions 3
• Emphasize monounsaturated and polyunsaturated fats while limiting saturated fats and avoiding trans fats 4

Physical Activity

• At least 150 minutes of moderate-intensity aerobic activity per week during pregnancy, preferably spread throughout the week 3, 4

Expected Response to Lifestyle Modifications

• 70-85% of women diagnosed with GDM can achieve glycemic control with lifestyle modifications alone 2, 4

Pharmacologic Therapy When Lifestyle Fails

First-Line: Insulin

• Insulin is the preferred and first-line pharmacological agent for GDM in India and internationally because it does not cross the placenta to a measurable extent 3, 4, 5
• Initial total daily insulin dose: 0.7-1.0 units/kg of current weight, distributed as 40% basal insulin and 60% prandial insulin 3
• Insulin has been proven to improve perinatal outcomes in large randomized studies 2

Why NOT Metformin or Glyburide as First-Line

• Both metformin and glyburide cross the placenta to the fetus 4, 5
• Metformin fails to provide adequate glycemic control in 25-28% of women with GDM 2, 4, 5
• Glyburide fails in 23% of women and is associated with higher rates of neonatal hypoglycemia and macrosomia compared to insulin 2, 4
• Long-term safety data for offspring exposed to these agents is concerning, with metformin exposure resulting in increased childhood weight, adiposity, and higher BMI 5
• Metformin cord blood levels equal or exceed maternal levels, indicating direct fetal exposure 5

Exceptional Circumstances for Metformin

• Metformin may be considered only in exceptional situations where patients require medical therapy but cannot safely use insulin 5
• Patients must be fully informed that metformin crosses the placenta and long-term safety data are lacking 5, 6

Team-Based Care Approach for Indian Setting

• A multidisciplinary team is ideal for managing GDM, comprising an obstetrician, diabetes physician, diabetes educator, dietitian, midwife, and pediatrician 1
• Team-based care through specialized centers improves outcomes 3
• Telehealth visits have been shown to improve outcomes compared with standard in-person care, reducing cesarean delivery and neonatal hypoglycemia 3, 4

Monitoring Strategy

• Self-monitoring of blood glucose is essential to assess treatment effectiveness 4, 1
• Monitor fasting and postprandial glucose levels targeting the specific thresholds listed above 3, 4
• Do not rely solely on A1C for monitoring, as it represents an average and may not capture physiologically relevant glycemic parameters in pregnancy 3
• A1C may need to be monitored more frequently than usual (e.g., monthly) due to changes in glycemic parameters during pregnancy 2

Critical Pitfalls to Avoid

• Do not delay insulin initiation in women with poor glycemic control on lifestyle modifications 3
• Do not use metformin for polycystic ovary syndrome beyond the first trimester 3
• Failure to recognize that most women can achieve targets with lifestyle alone may lead to premature pharmacological intervention 4
• Maintain normoglycemia in every pregnancy complicated by GDM until there is evidence that ignoring maternal hyperglycemia is safe when fetal growth appears normal 1

Long-Term Implications

• The maternal health and fetal outcome depends upon committed care by the team of diabetologists, obstetricians, and neonatologists 1
• Short-term intensive care provides long-term benefits in primary prevention of obesity, impaired glucose tolerance, and diabetes in offspring 1
• Preventive medicine for the child starts before birth through proper GDM management 1