What are the management and treatment options for diabetes during pregnancy?

Management of Diabetes in Pregnancy

Preconception Planning is Critical

All women with diabetes of childbearing potential must achieve A1C <6.5% before conception and use effective contraception until this target is met to prevent congenital malformations that occur during organogenesis at 5-8 weeks gestation. 1, 2

Essential Preconception Steps:

• Immediately discontinue teratogenic medications including ACE inhibitors, angiotensin receptor blockers, and statins 1, 2
• Initiate folic acid supplementation at 400 mg daily 2
• Complete comprehensive screening: thyroid function, renal function, ophthalmologic examination, and cardiovascular assessment 2
• The risk of congenital anomalies increases from 2-4% in the general population to 6-10% with A1C >7%, and as high as 20-25% with A1C >10% 3

Common pitfall: Most pregnancies are unplanned, making preconception optimization impossible. Therefore, family planning must be reviewed at every visit for all women with diabetes of reproductive age. 4

Glycemic Targets During Pregnancy

Insulin is the first-line and preferred medication for all types of diabetes during pregnancy because it does not cross the placenta. 1, 5, 2

Specific Blood Glucose Targets:

• Fasting glucose: <95 mg/dL 1, 5, 2
• 1-hour postprandial: <140 mg/dL 1, 5, 2
• 2-hour postprandial: <120 mg/dL 2
• A1C target: <6% if achievable without significant hypoglycemia 1, 2

A meta-analysis specifically found that a fasting glucose target of <90 mg/dL was most strongly associated with reduced macrosomia risk (odds ratio 0.53) in gestational diabetes during the third trimester. 6

Insulin Management Strategy

Type 1 and Type 2 Diabetes:

• Use physiologic basal-bolus regimens with rapid-acting insulin for meals and long-acting insulin for basal coverage 2
• Either multiple daily injections or continuous subcutaneous insulin infusion (insulin pump) are effective options 1, 7
• Insulin detemir is safe for use during pregnancy with no clear evidence of maternal or fetal risk in clinical trials of 310 pregnant women with type 1 diabetes 3

Continuous Glucose Monitoring:

• CGM should be used as an adjunct to, not replacement for, self-monitoring of blood glucose 2
• In type 1 diabetes, CGM reduces large-for-gestational-age births, neonatal hypoglycemia, and length of hospital stay 2

Critical caveat: Insulin requirements change dramatically during pregnancy. Insulin sensitivity increases throughout pregnancy, then decreases dramatically (by approximately 34%) immediately after placental delivery. 4, 2

Gestational Diabetes Mellitus Management

Initial Approach:

• Begin with medical nutrition therapy, referral to a registered dietitian nutritionist, and consistent carbohydrate intake 5, 2
• Implement regular moderate physical activity 5
• Monitor fasting and postprandial blood glucose levels 5

Medication Initiation:

• If glycemic targets are not achieved within 1-2 weeks of lifestyle modifications, initiate insulin 5, 2
• Metformin may be considered, though insulin remains preferred 5

Essential Adjunctive Therapies

Preeclampsia Prevention:

Prescribe low-dose aspirin 60-150 mg/day (typically 81 mg) by the end of the first trimester for all women with type 1 or type 2 diabetes. 1, 5

Retinopathy Monitoring:

• Women with preexisting diabetic retinopathy require close monitoring during pregnancy 1, 2
• Important caveat: Rapid implementation of euglycemia in the setting of retinopathy can worsen retinopathy progression 1

Hypoglycemia Prevention:

• Rates of severe hypoglycemia increase during pregnancy 8
• Glucagon must be available and close contacts trained in its use 8
• Lactation increases overnight hypoglycemia risk, requiring insulin dose adjustments 4

Postpartum Management Algorithm

Immediate Postpartum (First 24-48 Hours):

• Reduce insulin doses by approximately 34% immediately after placental delivery to prevent severe hypoglycemia 4, 2
• Insulin sensitivity returns to prepregnancy levels over 1-2 weeks 4
• Monitor closely for hypoglycemia, especially with breastfeeding and erratic sleep/eating schedules 4

For Women with Gestational Diabetes:

• Test for persistent diabetes or prediabetes at 4-12 weeks postpartum using a 75-g oral glucose tolerance test 1, 5
• Women with history of GDM have greatly increased risk of type 2 diabetes over time 4
• Both metformin and intensive lifestyle intervention reduce progression to diabetes by 35-40% over 10 years; only 5-6 women need treatment to prevent one case of diabetes over 3 years 4

Breastfeeding:

• All women with diabetes should be supported in breastfeeding attempts 4
• Breastfeeding confers longer-term metabolic benefits to both mother and offspring 4, 5

Contraception:

Implement effective contraception immediately postpartum—long-acting reversible contraception may be ideal. 4, 2

• Women with diabetes have the same contraception options as those without diabetes 4
• The risk of unplanned pregnancy outweighs the risk of any contraception option 4