What are the management strategies for diabetes and hypertension in pregnancy?

Management of Diabetes and Hypertension in Pregnancy

Insulin is the preferred first-line medication for managing both type 1 and type 2 diabetes during pregnancy, with strict glycemic targets of fasting glucose <95 mg/dL and 1-hour postprandial <140 mg/dL, while ACE inhibitors and ARBs must be immediately discontinued due to teratogenicity. 1

Preconception Management

Glycemic Optimization Before Pregnancy

• Target A1C <6.5% before conception to minimize congenital malformations, preeclampsia, and preterm birth. 2, 3
• Prescribe effective contraception and maintain its use until glycemic targets are achieved. 1, 2
• Organogenesis occurs at 5-8 weeks gestation, often before women realize they are pregnant, making preconception control critical. 2

Medication Review and Adjustment

• Immediately discontinue ACE inhibitors, angiotensin receptor blockers, and statins at conception due to teratogenic risk. 1
• Transition to pregnancy-safe antihypertensive agents (such as labetalol, nifedipine, or methyldopa) before conception if hypertension requires treatment. 1
• Initiate folic acid supplementation 400-800 mg/day. 1

Comprehensive Screening

• Assess for diabetic complications: comprehensive ophthalmologic exam, ECG (if age ≥35 or cardiac risk factors), lipid panel, serum creatinine, TSH, and urine albumin-to-creatinine ratio. 1
• Screen for retinopathy, nephropathy, and neuropathy as these complications increase risk of disease progression during pregnancy. 1

Glycemic Targets During Pregnancy

Blood Glucose Goals

• Fasting plasma glucose <95 mg/dL (<5.3 mmol/L) 1, 2
• 1-hour postprandial glucose <140 mg/dL (<7.8 mmol/L) 1, 2
• 2-hour postprandial glucose <120 mg/dL (<6.7 mmol/L) 1, 2

A1C Targets

• Optimal A1C goal is <6% (<42 mmol/mol) if achievable without significant hypoglycemia. 1, 2
• A1C may be relaxed to <7% (<53 mmol/mol) if necessary to prevent hypoglycemia. 1
• A1C is physiologically lower during pregnancy due to increased red blood cell turnover. 1

Insulin Management

Insulin as First-Line Therapy

• Insulin is the preferred agent because it does not cross the placenta to a measurable extent. 1, 2, 4
• Both multiple daily injections and continuous subcutaneous insulin infusion are acceptable delivery strategies; neither has proven superiority. 1
• Implement physiologic basal-bolus regimens with rapid-acting insulin for meals and long-acting insulin for basal coverage. 3

Type 1 Diabetes Considerations

• Women with type 1 diabetes have increased hypoglycemia risk in the first trimester with altered counterregulatory response. 1
• Provide education to patients and family members on hypoglycemia prevention, recognition, and treatment before, during, and after pregnancy. 1
• Prescribe ketone strips and educate on diabetic ketoacidosis (DKA) prevention, as DKA occurs at lower glucose levels during pregnancy and carries high stillbirth risk. 1

Type 2 Diabetes Considerations

• Glycemic control is often easier to achieve than in type 1 diabetes but may require much higher insulin doses, sometimes necessitating concentrated insulin formulations. 1
• Risk for hypertension and other comorbidities may be as high or higher than with type 1 diabetes. 1
• Pregnancy loss appears more prevalent in the third trimester with type 2 diabetes compared to first trimester losses in type 1 diabetes. 1

Monitoring Strategy

Blood Glucose Monitoring

• Fasting, preprandial, and postprandial blood glucose monitoring are recommended to achieve optimal glucose levels. 1
• Self-monitoring of blood glucose is the primary tool for glycemic management, with focus on postprandial monitoring. 3

Continuous Glucose Monitoring (CGM)

• CGM can help achieve glycemic goals (time in range, time above range) in type 1 diabetes and pregnancy. 1
• CGM may be beneficial for other types of diabetes in pregnancy. 1
• Use CGM as an adjunct to, not a replacement for, self-monitoring of blood glucose. 3

Hypertension Management

Blood Pressure Targets

• Target blood pressure of 110-135/85 mmHg is suggested to reduce risk of accelerated maternal hypertension while minimizing impaired fetal growth. 1
• Chronic hypertension treatment goals are systolic blood pressure 110-129 mmHg and diastolic blood pressure 65-79 mmHg. 5

Medication Selection

• Use pregnancy-safe antihypertensives: labetalol, nifedipine, or methyldopa are preferred agents. 6
• Never use ACE inhibitors or ARBs during pregnancy due to fetotoxicity in the second and third trimesters. 1, 6

Preeclampsia Prevention

Women with type 1 or type 2 diabetes should be prescribed low-dose aspirin 100-150 mg/day starting at 12 to 16 weeks of gestation to lower the risk of preeclampsia. 1

• A dosage of 162 mg/day may be acceptable; in the U.S., low-dose aspirin is available in 81-mg tablets. 1
• Low-dose aspirin >100 mg is required for effectiveness; 81 mg/day is insufficient. 1
• Continue aspirin until delivery. 1

Retinopathy Monitoring

• Women with preexisting diabetic retinopathy need close monitoring during pregnancy to assess for progression and provide treatment if indicated. 1, 2
• Comprehensive ophthalmologic examination should be performed at baseline and as needed throughout pregnancy. 3
• Rapid implementation of tight glycemic control in the setting of retinopathy is associated with worsening of retinopathy. 1, 2

Medical Nutrition Therapy

• Consistent carbohydrate intake is important to match insulin dosing and avoid glucose fluctuations. 2, 3
• The food plan should provide adequate calories to promote fetal/neonatal and maternal health, achieve glycemic goals, and promote appropriate gestational weight gain. 2
• Recommended weight gain for overweight women is 15-25 lb and for obese women is 10-20 lb. 1

Postpartum Management

Immediate Postpartum Period

• Insulin requirements decrease dramatically after delivery of the placenta due to rapid increase in insulin sensitivity. 1, 2
• Close monitoring and rapid insulin dose reduction are essential in the immediate postpartum period to prevent hypoglycemia. 3
• Women become very insulin sensitive immediately following delivery and may initially require much less insulin than in the prepartum period. 1

Gestational Diabetes Follow-up

• 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 using nonpregnancy criteria. 1, 2
• Women with gestational diabetes have increased risk of developing type 2 diabetes and require ongoing screening. 3

Contraception Planning

• A contraceptive plan should be discussed and implemented with all women with diabetes of reproductive potential. 2
• Effective contraception prevents pregnancy until glycemic targets are achieved for future pregnancies. 1

Common Pitfalls and Caveats

• Avoid delaying insulin initiation in gestational diabetes: If glucose targets are not achieved within 1-2 weeks of medical nutrition therapy, initiate insulin promptly. 3
• Monitor for hypokalemia with intravenous insulin: Insulin stimulates potassium movement into cells, potentially causing respiratory paralysis, ventricular arrhythmia, and death if untreated. 4
• Do not rely solely on A1C during pregnancy: Use frequent blood glucose monitoring as A1C is physiologically lower during pregnancy and may not reflect true glycemic control. 1
• Beware of DKA at lower glucose levels: Pregnancy is a ketogenic state, and women with diabetes are at risk for DKA at lower blood glucose levels than in the nonpregnant state. 1