What is the recommended management for type 2 diabetes (T2D) in pregnancy?

Management of Type 2 Diabetes in Pregnancy

Primary Treatment Approach

Insulin is the preferred and first-line pharmacologic agent for managing type 2 diabetes in pregnancy, as it does not cross the placenta and provides the safest option for both mother and fetus. 1, 2

Glycemic Targets

Achieve the following blood glucose targets through frequent monitoring 1:

• Fasting glucose: 70-95 mg/dL (3.9-5.3 mmol/L) 1
• One-hour postprandial: 110-140 mg/dL (6.1-7.8 mmol/L) 1
• Two-hour postprandial: 100-120 mg/dL (5.6-6.7 mmol/L) 1
• A1C target: <6% to <7% (42-53 mmol/mol), individualized to avoid hypoglycemia 1, 2

Monitor both fasting and postprandial glucose levels rather than relying solely on A1C, as pregnancy physiology alters red blood cell turnover and A1C may not capture postprandial hyperglycemia that drives macrosomia. 1

Initial Management Strategy

Lifestyle Modifications First

Begin with medical nutrition therapy, physical activity, and weight management before initiating pharmacologic therapy 1:

• Minimum nutritional requirements: 175g carbohydrate, 71g protein, 28g fiber daily 1
• Weight gain targets: 15-25 lb (6.8-11.3 kg) for overweight; 10-20 lb (4.5-9.1 kg) for obesity 1
• Never recommend weight loss during pregnancy due to increased risk of small-for-gestational-age infants 1

When to Initiate Insulin

Add insulin when lifestyle modifications fail to achieve glycemic targets, or immediately if presenting with significant hyperglycemia 1

Insulin Management Protocol

Dosing Strategy

• Use multiple daily injections with basal-bolus regimen or insulin pump technology 1
• Expect insulin requirements to double by the third trimester, with linear increases of approximately 5% per week starting around 16 weeks gestation 1
• May require concentrated insulin formulations due to high insulin resistance in type 2 diabetes 1

Monitoring Frequency

• Check blood glucose: Fasting and postprandial (either 1-hour or 2-hour after meals) 1
• Monitor A1C monthly as a secondary measure, not primary control metric 1
• Adjust insulin doses frequently (every 2-3 weeks as pregnancy progresses) based on glucose patterns 2

Alternative Pharmacologic Options (Second-Line)

While insulin is preferred, metformin may be considered as adjunctive therapy to insulin in type 2 diabetes 1:

• Metformin added to insulin reduces maternal weight gain and cesarean births but doubles the risk of small-for-gestational-age neonates 1
• Both metformin and glyburide cross the placenta and lack long-term safety data 1
• Do not use metformin or glyburide as monotherapy in type 2 diabetes during pregnancy 1

Essential Adjunctive Therapies

Aspirin for Preeclampsia Prevention

Prescribe low-dose aspirin 100-150 mg daily (or 162 mg if using U.S. 81-mg tablets) starting at 12-16 weeks gestation to reduce preeclampsia risk, as diabetes significantly increases this risk. 1

Medication Safety

Immediately discontinue the following medications at conception 1:

• ACE inhibitors (cause fetal renal dysplasia, oligohydramnios)
• Angiotensin receptor blockers
• Statins

Blood Pressure Management

Initiate or titrate antihypertensive therapy at blood pressure ≥140/90 mmHg for better pregnancy outcomes without increasing small-for-gestational-age risk 1

Critical Monitoring for Complications

Retinopathy Screening

Rapid implementation of euglycemia worsens retinopathy in those with existing disease; screen for retinopathy before pregnancy and monitor closely throughout 1

Hypoglycemia Risk

Educate patients and family members on hypoglycemia prevention, recognition, and treatment before, during, and after pregnancy, as counter-regulatory responses are altered in pregnancy 1, 2

Third Trimester Surveillance

Type 2 diabetes carries higher risk of third-trimester pregnancy loss compared to type 1 diabetes (which peaks in first trimester); intensify fetal surveillance accordingly 1

Postpartum Management

Insulin requirements drop dramatically immediately after placental delivery 1, 2:

• Reduce insulin to 50% of end-pregnancy doses or 80% of pre-pregnancy doses 3
• Monitor closely for hypoglycemia, especially during breastfeeding 3
• Never discontinue basal insulin in insulin-dependent patients due to ketoacidosis risk 3

Common Pitfalls to Avoid

• Do not rely on A1C alone for glucose control assessment; it underestimates postprandial hyperglycemia in pregnancy 1
• Do not delay insulin initiation when lifestyle modifications fail to achieve targets 1
• Do not continue ACE inhibitors, ARBs, or statins in sexually active women of childbearing age without reliable contraception 1
• Do not use aspirin doses <100 mg for preeclampsia prevention; they are ineffective 1
• Do not forget that insulin needs increase linearly through week 36; failure to uptitrate leads to poor control 1

Specialized Care Referral

Refer to a specialized center with multidisciplinary team (maternal-fetal medicine, endocrinology, dietitian, nurse, social worker) due to the complexity of insulin management and high-risk nature of diabetic pregnancy. 1