How do you manage a full-term pregnant lady with gestational diabetes (GDM) preparing for an elective cesarean section (C-section)?

Management of Full-Term Pregnant Woman with Gestational Diabetes Preparing for Elective Cesarean Section

What is Gestational Diabetes?

Gestational diabetes mellitus (GDM) is carbohydrate intolerance with onset or first recognition during pregnancy, diagnosed by oral glucose tolerance test with fasting glucose ≥92 mg/dL, 1-hour ≥180 mg/dL, or 2-hour ≥153 mg/dL. 1, 2 GDM is the most common medical complication of pregnancy, affecting approximately 4-13% of pregnancies depending on population and diagnostic criteria used 1, 3. It increases risks of fetal macrosomia, birth trauma, neonatal hypoglycemia, maternal hypertensive disorders, and long-term development of type 2 diabetes in both mother and offspring 4, 5.

Preoperative Preparation

Timing of Delivery

Delivery during the 38th week of gestation is recommended for women with GDM, as prolongation past 38 weeks increases fetal macrosomia risk without reducing cesarean rates. 1

• For GDM controlled by diet/exercise alone: delivery at 39 0/7 to 40 6/7 weeks is appropriate 4
• For GDM requiring medications (insulin or oral agents): delivery at 39 0/7 to 39 6/7 weeks is preferred 4
• GDM alone is not an indication for cesarean delivery before 38 completed weeks 1

Fetal Assessment

Ultrasound assessment for estimated fetal weight should be performed, with particular attention to macrosomia (>4,000g), as this influences delivery planning. 4

• If estimated fetal weight exceeds 4,500g, discuss risks and benefits of prelabor cesarean delivery due to increased shoulder dystocia risk 4, 6
• Intensified fetal surveillance during the last 8-10 weeks is appropriate, particularly when fasting glucose exceeds 105 mg/dL 1, 6

Maternal Assessment

Blood pressure and urine protein monitoring should be performed to detect preeclampsia, which occurs at higher rates in women with GDM. 1

Perioperative Glycemic Management

Transition to Intravenous Insulin

For women with GDM requiring insulin or glyburide, transition to intravenous insulin infusion during cesarean section to prevent maternal hypoglycemia and ketosis. 7

• Use the patient's current basal insulin rate as the starting point for IV insulin infusion 7
• Administer 10% glucose infusion concurrently with insulin to prevent hypoglycemia during fasting 7, 6
• For women controlled on diet alone, IV insulin may not be necessary, but frequent glucose monitoring is still required 4

Intraoperative Glycemic Targets

Target blood glucose range of 110-160 mg/dL (6.1-8.9 mmol/L) during cesarean section to optimize wound healing while avoiding hypoglycemia. 7

• Monitor blood glucose hourly during the procedure 7
• Adjust insulin infusion rates to maintain target range 7
• Regional anesthesia is preferred over general anesthesia to reduce hyperglycemic stress response 7

Immediate Postpartum Management

Insulin Dose Adjustment

Immediately after placental delivery, insulin requirements drop dramatically—resume basal-bolus insulin at 50% of end-of-pregnancy doses or 80% of pre-pregnancy doses to minimize hypoglycemia risk. 7, 6

• For women with GDM controlled by diet alone, insulin is typically not needed postpartum 4
• For women who required insulin during pregnancy, continue at reduced doses with frequent monitoring 7
• Never discontinue basal insulin completely in women with possible undiagnosed type 1 diabetes 6

Postpartum Glycemic Targets

Target blood glucose of 110-160 mg/dL for the first 48 hours post-cesarean to optimize wound healing, then liberalize to 100-180 mg/dL if healing progresses well. 7

• Implement correction dose sliding scale based on pre-meal and bedtime glucose values 7
• Ensure regular meals and snacks once tolerating oral intake to prevent hypoglycemia 7
• Never give correction insulin without adequate carbohydrate intake 7

Monitoring for Complications

Monitor for ketosis, especially if blood glucose exceeds 200 mg/dL or patient is symptomatic, by checking urine or serum ketones. 7

• Be vigilant for hypoglycemia, particularly during breastfeeding and with irregular sleep patterns 6
• Monitor wound healing closely, as hyperglycemia increases infection risk 7

Neonatal Considerations

Mandatory pediatric assessment at delivery for neonatal hypoglycemia risk and respiratory distress is required, with consideration of NICU admission for close monitoring. 7

• Neonatal hypoglycemia occurs due to fetal hyperinsulinemia persisting 24-48 hours postpartum 7
• Prompt treatment is necessary to prevent permanent neurological injury 7
• Encourage breastfeeding, as it benefits both mother and infant long-term 1, 8

Long-Term Follow-Up

Reclassification of maternal glycemic status must be performed at 6-12 weeks postpartum using a 75g oral glucose tolerance test with non-pregnancy criteria. 1

• Women with GDM have greatly increased risk of developing type 2 diabetes 1, 5
• Repeat glucose assessment every 1-3 years depending on other risk factors 1, 2
• Lifestyle modifications including weight management and physical activity should be emphasized 2, 8
• Offspring should be followed for development of obesity and glucose intolerance 1

Critical Safety Pitfalls to Avoid

• Do not continue full pregnancy insulin doses postpartum—this causes severe hypoglycemia as placental hormones are removed 7, 6
• Do not allow maternal glucose to exceed 160 mg/dL perioperatively—this increases wound infection risk and neonatal hypoglycemia 7
• Do not withhold glucose infusion during IV insulin administration—this causes maternal hypoglycemia and ketosis 7, 6
• Do not delay neonatal glucose monitoring—hypoglycemia can cause permanent neurological damage if untreated 7