What is the management plan for a pregnant woman with diabetes mellitus (DM), including necessary tests and interventions?

Management and Tests for Diabetes in Pregnancy

Pregnant women with diabetes require intensive glycemic control with insulin as first-line therapy, targeting fasting glucose <95 mg/dL and 1-hour postprandial <140 mg/dL, combined with comprehensive screening for complications and close monitoring throughout pregnancy. 1, 2

Preconception Care and Initial Assessment

Essential Preconception Testing

Before pregnancy or at first prenatal visit, perform comprehensive diabetes-specific testing including: 1

• A1C measurement - target <6.5% before conception to minimize congenital malformations 1, 2
• Serum creatinine and urine albumin-to-creatinine ratio - assess for nephropathy 1
• Comprehensive dilated eye exam by ophthalmologist - screen for retinopathy 1
• ECG in women ≥35 years or with cardiac symptoms/risk factors 1
• Lipid panel 1
• TSH - particularly important in type 1 diabetes due to 5-10% coincidence of thyroid dysfunction 1
• Blood pressure measurement including orthostatic changes 1
• Comprehensive foot exam 1
• Neurological exam for autonomic neuropathy (gastroparesis, hypoglycemia unawareness, orthostatic hypotension) 1

Critical Medication Review

Immediately discontinue ACE inhibitors, angiotensin receptor blockers, and statins due to teratogenic risk. 1, 2 Women using these medications need alternative therapies stabilized before conception. 1

Contraception Until Glycemic Goals Achieved

Prescribe effective contraception and do not discontinue until A1C <6.5% is achieved, as organogenesis occurs at 5-8 weeks gestation when many women don't yet know they're pregnant. 2

Glycemic Targets During Pregnancy

Blood Glucose Goals

Fasting, preprandial, and postprandial monitoring are mandatory. Target the following glucose levels: 1, 2

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

Postprandial monitoring is superior to preprandial monitoring alone and is associated with better glycemic control and lower risk of preeclampsia. 1

A1C Goals

• Optimal target A1C <6% (<42 mmol/mol) if achievable without significant hypoglycemia 1, 2
• May relax to <7% (<53 mmol/mol) if necessary to prevent hypoglycemia 1
• A1C is slightly lower during pregnancy due to increased red blood cell turnover 1
• A1C may not fully capture postprandial hyperglycemia, which drives adverse outcomes, so blood glucose monitoring remains essential 1

Insulin Management

First-Line Therapy

Insulin is the preferred and recommended first-line pharmacologic agent because it does not cross the placenta to a measurable extent. 3, 2, 4 Either multiple daily injections or insulin pump therapy can be used effectively. 2

Insulin Requirements Throughout Pregnancy

• Insulin requirements typically decrease during first trimester 4
• Increase during second and third trimesters 4, 5
• Decline rapidly after delivery of placenta 2, 4

Continuous Glucose Monitoring

CGM can help achieve glycemic goals (time in range, time above range) in type 1 diabetes and pregnancy and may be beneficial for other types of diabetes in pregnancy. 1 The CONCEPTT study demonstrated improved outcomes with CGM use. 1

Medical Nutrition Therapy

Referral and Dietary Goals

Refer to registered dietitian nutritionist within first week of diagnosis to establish individualized food plan. 1, 3 The diet must provide: 3

• Minimum 175g carbohydrate daily - do not restrict below this level as it may compromise fetal growth 3
• 71g protein daily 3
• 28g fiber daily 3
• Emphasis on monounsaturated and polyunsaturated fats while limiting saturated fats and avoiding trans fats 1, 3

Carbohydrate Management

Consistent carbohydrate intake is critical to match insulin dosing and avoid hyperglycemia or hypoglycemia. 1, 2 Establish insulin-to-carbohydrate ratios. 1 Focus on nutrient-dense whole foods including fruits, vegetables, legumes, whole grains, and healthy fats with omega-3 fatty acids. 1

Avoid ketogenic diets, Paleo diets, and any diet severely restricting macronutrients during pregnancy. 1

Monitoring Schedule During Pregnancy

Blood Glucose Monitoring Frequency

• Fasting glucose daily upon waking 3
• Postprandial glucose after each main meal (breakfast, lunch, dinner) 3
• Choose either 1-hour OR 2-hour postprandial measurements consistently 3

Fetal Surveillance

• Ultrasound monitoring of fetal abdominal circumference beginning in second and early third trimesters, repeated every 2-4 weeks 3
• Consider intensifying glycemic control when fetal abdominal circumference >75th percentile 3
• Teach mothers to monitor fetal movements during last 8-10 weeks and report any reduction immediately 3

Maternal Surveillance

• Blood pressure and urinary protein at each prenatal visit to detect preeclampsia 3
• Monthly A1C if used (though blood glucose monitoring is primary) 3

Retinopathy Monitoring

Women with preexisting diabetic retinopathy need close monitoring during pregnancy to assess for progression and provide treatment if indicated. 1, 2 Rapid implementation of euglycemia can worsen retinopathy, so glycemic optimization should be gradual when retinopathy is present. 2

Preeclampsia Prevention

Prescribe low-dose aspirin 60-150 mg/day by end of first trimester (soon after 12 weeks' gestation) to lower risk of preeclampsia in all women with type 1 or type 2 diabetes. 2, 6

Special Considerations

Hypoglycemia Risk

Rates of severe hypoglycemia increase during pregnancy. 6 Glucagon should be available to the patient and close contacts should be trained in its use. 6 Hypoglycemia unawareness requires special caution. 4

Euglycemic DKA in Pregnancy

Pregnancy creates accelerated starvation and ketosis at lower glucose levels - DKA can occur with glucose <200-250 mg/dL. 7 If euglycemic DKA develops, start continuous IV insulin immediately even with normal glucose, while simultaneously administering 10% dextrose IV to meet placental and fetal carbohydrate demands. 7 Monitor β-hydroxybutyrate levels to assess treatment response. 7

Nephropathy Considerations

Women with protein excretion ≥190 mg/24h are at increased risk for hypertensive disorders during pregnancy; those with ≥400 mg/24h are also at risk for intrauterine growth retardation. 1 Blood pressure goals must be carefully considered, with lower treatment thresholds potentially required. 6

Postpartum Management

Immediate Postpartum

Insulin requirements decrease dramatically after delivery of the placenta. 2, 4 Anticipate rapid reduction in insulin needs. 1

Testing for Persistent Diabetes

All women with gestational diabetes must be tested at 4-12 weeks postpartum using 75g oral glucose tolerance test with non-pregnancy diagnostic criteria. 3, 2 Do not use A1C at this visit because concentration may still be influenced by pregnancy changes and/or peripartum blood loss. 3

Long-Term Follow-Up

Women with history of gestational diabetes have 50-70% risk of developing type 2 diabetes over 15-25 years. 3, 2 Perform lifelong screening for diabetes at least every 3 years. 3

Contraception Planning

Discuss and implement contraceptive plan with all women with diabetes of reproductive potential before discharge. 2, 6 Long-acting reversible contraception should be emphasized to allow appropriate preconception planning for future pregnancies. 6

Common Pitfalls to Avoid

• Do not wait for hyperglycemia to diagnose DKA in pregnancy - euglycemic DKA is common and easily missed 7
• Do not give insulin without dextrose in pregnant women with DKA - this fails to meet fetal metabolic needs 7
• Do not reduce carbohydrates below 175g/day - may compromise fetal growth 3
• Do not rely solely on A1C - it doesn't adequately capture postprandial hyperglycemia that drives macrosomia 3
• Do not use metformin or glyburide as first-line therapy - inferior outcomes compared to insulin 3