What is the management approach for a pregnant patient with diabetes and a history of hypertension?

Management of Diabetes in Pregnancy with History of Hypertension

Immediate Medication Review and Discontinuation

The most critical first step is immediately discontinuing all teratogenic antihypertensive medications—specifically ACE inhibitors, angiotensin receptor blockers, and statins—as these cause fetal renal dysplasia, oligohydramnios, pulmonary hypoplasia, and intrauterine growth restriction. 1, 2, 3

• Every day of continued exposure to ACE inhibitors or ARBs increases fetal risk, making this the highest priority action at any pregnancy visit 2
• Statins are pregnancy category X and must be stopped immediately in all pregnant women 1, 3
• Atenolol should also be discontinued due to association with fetal growth restriction 3

Safe Antihypertensive Substitution

Switch to pregnancy-safe antihypertensives immediately: methyldopa, labetalol, or long-acting nifedipine as first-line options. 1, 2, 3

• Target blood pressure of 110-135/85 mmHg balances reducing maternal hypertension risk while minimizing impaired fetal growth 1, 2
• Blood pressure targets lower than 110/80 mmHg may impair fetal growth, especially with placental insufficiency 1
• Chronic diuretic use is not recommended as it restricts maternal plasma volume and may reduce uteroplacental perfusion 1

Preeclampsia Prevention Protocol

Initiate low-dose aspirin 100-150 mg daily immediately (ideally by 12-16 weeks gestation) as women with both diabetes and hypertension have significantly elevated preeclampsia risk. 1, 2

• Doses less than 100 mg are ineffective; 100-150 mg is required for preeclampsia prevention 1
• The standard 81 mg dose available in the U.S. is suboptimal; consider 162 mg (two 81 mg tablets) 1
• Starting aspirin after 16 weeks reduces effectiveness 2

Insulin as Mandatory First-Line Therapy

Insulin is the mandatory first-line treatment for all women with preexisting diabetes during pregnancy, as it does not cross the placenta and is the safest option. 4, 2, 3

• Implement physiologic basal-bolus regimens with rapid-acting insulin for meals and long-acting insulin for basal coverage 2
• Both multiple daily injections and continuous subcutaneous insulin infusion (pump therapy) are appropriate, with neither proven superior 4
• Insulin requirements often increase dramatically during pregnancy but drop to approximately 50-80% of pre-pregnancy doses immediately after delivery 1, 4

Strict Glycemic Targets

Achieve fasting glucose <95 mg/dL, 1-hour postprandial <140 mg/dL, and 2-hour postprandial <120 mg/dL through intensive glucose monitoring. 4, 2

• Target A1C <6% if achievable without significant hypoglycemia; may relax to <7% if necessary to prevent hypoglycemia 4, 2
• Perform both fasting and postprandial blood glucose monitoring 4-7 times daily 4, 5
• Continuous glucose monitoring (CGM) improves glycemic control and reduces hypoglycemia risk when used alongside self-monitoring 4

Screening for Diabetes Complications

Perform comprehensive screening for diabetic complications that may worsen during pregnancy or affect maternal-fetal outcomes. 4, 2

• Comprehensive ophthalmologic examination at baseline and as needed throughout pregnancy, as rapid glycemic improvement can worsen retinopathy 1, 4, 2
• Serum creatinine and urine albumin-to-creatinine ratio to assess nephropathy 4, 2
• ECG if age ≥35 years or cardiac risk factors present 4
• TSH screening 4

Medical Nutrition Therapy

Refer to a registered dietitian nutritionist to establish a food plan with consistent carbohydrate intake matched to insulin dosing. 4, 2

• Recommended weight gain for women with overweight is 15-25 lb; for women with obesity is 10-20 lb 1
• Consistent carbohydrate amounts prevent hyperglycemia and hypoglycemia 4, 2
• Establish insulin-to-carbohydrate ratios for meal coverage 4

Diabetic Ketoacidosis Prevention

Women with type 1 diabetes are at risk for DKA at lower glucose levels during pregnancy and should be prescribed ketone strips with education on prevention and detection. 1

• DKA carries high risk of stillbirth 1
• Women in DKA unable to eat often require 10% dextrose with insulin drip to meet placental and fetal carbohydrate demands 1

Frequent Monitoring Schedule

Schedule antenatal visits every 1-2 weeks throughout pregnancy with the multidisciplinary diabetes team. 6

• Frequent phone contact for insulin dose adjustments between visits 1
• Monitor fetal growth and development at each visit 6
• Assess for signs of preeclampsia, worsening hypertension, and diabetic complications 6

Labor and Delivery Planning

Develop an individualized delivery plan with transition to intravenous insulin infusion during active labor. 4, 2

• Administer 10% glucose infusion alongside insulin to prevent maternal hypoglycemia and ketosis during labor 4, 2
• Timing of delivery depends on maternal glucose control, fetal growth, and complications 6

Immediate Postpartum Management

Reduce insulin immediately after placental delivery to either 80% of pre-pregnancy doses or 50% of end-pregnancy doses to prevent severe hypoglycemia. 4, 2

• Target postpartum blood glucose 110-160 mg/dL 4
• Insulin resistance decreases dramatically after delivery 1
• Support breastfeeding as it provides metabolic benefits to both mother and offspring 4

Common Pitfalls to Avoid

• Do not delay medication review: Every day of ACE inhibitor/ARB exposure increases fetal risk 2, 3
• Do not use 81 mg aspirin alone: Doses <100 mg are ineffective for preeclampsia prevention 1
• Do not target blood pressure <110/80 mmHg: This may impair fetal growth 1, 2
• Do not implement rapid glycemic improvement in women with retinopathy: This can worsen retinopathy 1, 2
• Do not forget glucagon availability: Severe hypoglycemia risk increases during pregnancy; train close contacts in glucagon use 7