What is the recommended approach for managing diabetes in pregnancy?

Management of Diabetes in Pregnancy

Insulin is the preferred first-line medication for managing diabetes during pregnancy, combined with intensive blood glucose monitoring and medical nutrition therapy to achieve strict glycemic targets that reduce maternal and fetal complications. 1, 2, 3

Preconception Planning (Essential for Optimal Outcomes)

Achieve A1C <6.5% before conception to minimize the risk of congenital malformations, spontaneous abortion, preeclampsia, and preterm birth. 3, 4 The critical window is 5-8 weeks gestation when organogenesis occurs, often before women realize they are pregnant. 4

• Immediately discontinue teratogenic medications: ACE inhibitors, angiotensin receptor blockers, and statins must be stopped before conception. 3, 4
• Initiate folic acid supplementation at 400 mg daily. 3
• Use effective contraception until glycemic targets are achieved. 1, 3
• Complete comprehensive screening: thyroid function, renal function, dilated ophthalmologic examination, and cardiovascular assessment. 3

Preconception counseling should explain risks to mother and fetus and include glycemic goal setting, lifestyle management, and medical nutrition therapy. 1 Studies demonstrate that multidisciplinary care from preconception through pregnancy improves diabetes and pregnancy outcomes. 1

Glycemic Targets During Pregnancy

Target A1C <6% if achievable without significant hypoglycemia, with relaxation to <7% if necessary to prevent hypoglycemia. 1, 3 A1C is physiologically lower in pregnancy due to increased red blood cell turnover. 1

Blood glucose targets (American Diabetes Association/American College of Obstetricians and Gynecologists):

• Fasting: <95 mg/dL (5.3 mmol/L) 1, 3, 4
• 1-hour postprandial: <140 mg/dL (7.8 mmol/L) OR 1, 3, 4
• 2-hour postprandial: <120 mg/dL (6.7 mmol/L) 1, 3

These stricter targets reflect pregnancy physiology: fasting glucose is lower due to insulin-independent fetal and placental glucose uptake, while postprandial hyperglycemia occurs from diabetogenic placental hormones. 1

Insulin Management Strategy

Insulin does not cross the placenta to a measurable extent and is the safest pharmacologic option for both mother and fetus. 2, 3, 4

Insulin Regimen Selection

• Physiologic basal-bolus regimens with rapid-acting insulin for meals and long-acting insulin for basal coverage are recommended. 3, 4
• Both multiple daily injections (MDI) and continuous subcutaneous insulin infusion (CSII) are appropriate delivery strategies for type 1 diabetes. 2
• Insulin dosing must be adjusted based on blood glucose monitoring results, carbohydrate intake, physical activity levels, and stage of pregnancy. 2

Insulin Requirements Throughout Pregnancy

Early pregnancy (first trimester): Enhanced insulin sensitivity, lower glucose levels, and lower insulin requirements. 1

Second and early third trimesters: Insulin resistance increases exponentially, requiring frequent dose adjustments. 1 Regular evaluation every 2-3 weeks is necessary. 2

Third trimester: Insulin requirements may double compared to pre-pregnancy doses. 2

Critical warning: A rapid reduction in insulin requirements may indicate placental insufficiency and requires immediate medical evaluation. 2

Blood Glucose Monitoring

Fasting and postprandial self-monitoring of blood glucose is essential for achieving metabolic control in both gestational diabetes and preexisting diabetes. 1, 3

• Preprandial testing is recommended for women using insulin pumps or basal-bolus therapy to adjust premeal rapid-acting insulin dosage. 1
• Postprandial monitoring is associated with better glycemic control and lower risk of preeclampsia. 1
• Continuous glucose monitoring (CGM) should be used as an adjunct to, not a replacement for, self-monitoring. 3 CGM reduces large-for-gestational-age births, neonatal hypoglycemia, and length of hospital stay in type 1 diabetes. 3

Medical Nutrition Therapy

Referral to a registered dietitian is essential to establish a food plan, insulin-to-carbohydrate ratio, and weight gain goals. 1

• Consistent carbohydrate intake is critical to match insulin dosing and avoid hyperglycemia or hypoglycemia. 1, 2
• The food plan should provide adequate calories to promote fetal/neonatal and maternal health while achieving glycemic goals. 4

Ophthalmologic Monitoring

Women with preexisting type 1 or type 2 diabetes require dilated eye examinations ideally before pregnancy or in the first trimester, then every trimester and for 1 year postpartum. 1, 3

Important caveat: Rapid implementation of euglycemia in the setting of retinopathy is associated with worsening of retinopathy. 4 This requires careful balancing of glycemic improvement with ophthalmologic monitoring.

Preeclampsia Prevention

Women with type 1 or type 2 diabetes should be prescribed low-dose aspirin 60-150 mg/day by the end of the first trimester to lower the risk of preeclampsia. 4

Hypoglycemia Management

Education on hypoglycemia prevention, recognition, and treatment is mandatory for all pregnant women with diabetes and their family members. 2, 3, 4 The enhanced insulin sensitivity in early pregnancy and strict glycemic targets increase hypoglycemia risk.

Postpartum Management

Insulin requirements decrease dramatically after delivery of the placenta, necessitating close monitoring and rapid insulin dose reduction in the immediate postpartum period to prevent hypoglycemia. 2, 3, 4

• Women with gestational diabetes should be tested for persistent diabetes or prediabetes at 4-12 weeks postpartum with a 75-g oral glucose tolerance test. 4
• A contraceptive plan should be discussed and implemented with all women with diabetes of reproductive potential. 4
• Breastfeeding is highly encouraged due to maternal benefits including increased insulin sensitivity and weight loss, plus infant benefits including reduced prevalence of overweight. 5

Common Pitfalls to Avoid

• Failing to achieve preconception glycemic control: Organogenesis occurs at 5-8 weeks, often before pregnancy recognition. 4
• Continuing teratogenic medications: ACE inhibitors, ARBs, and statins must be discontinued before conception. 3, 4
• Inadequate postprandial monitoring: Postprandial monitoring is superior to fasting-only monitoring for preventing complications. 1
• Insufficient insulin dose adjustments: Insulin resistance increases exponentially in the second trimester, requiring proactive dose increases. 1
• Overlooking postpartum hypoglycemia risk: Failure to reduce insulin doses immediately after delivery can cause severe hypoglycemia. 2, 3, 4