What is the recommended management for type 2 diabetes mellitus (T2DM) in pregnancy?

Management of Type 2 Diabetes Mellitus in Pregnancy

Insulin is the preferred agent for management of type 2 diabetes mellitus during pregnancy, as it does not cross the placenta to a measurable extent and has the strongest safety profile for both mother and fetus. 1, 2

First-Line Treatment Approach

• Insulin therapy should be initiated or continued as the primary treatment for T2DM in pregnancy
  • Both multiple daily injections and insulin pump therapy are appropriate delivery methods 2
  • Insulin requirements typically increase significantly during the second and third trimesters due to increasing insulin resistance
  • Higher doses may be needed compared to type 1 diabetes, sometimes requiring concentrated insulin formulations 1, 2

Glycemic Targets

• Strict glycemic control is essential to reduce maternal and fetal complications:
  • Fasting: 70-95 mg/dL
  • 1-hour postprandial: 110-140 mg/dL
  • 2-hour postprandial: 100-120 mg/dL
  • A1C target <6% if achievable without significant hypoglycemia 2

Lifestyle Management

• Medical nutrition therapy with an individualized meal plan developed by a registered dietitian
• Weight gain recommendations:
  • Overweight women: 15-25 lbs
  • Obese women: 10-20 lbs 1, 2
• Regular physical activity as tolerated and appropriate for pregnancy

Special Considerations and Monitoring

1. Hypoglycemia risk: Women have increased risk of hypoglycemia in the first trimester and altered counterregulatory responses that may decrease hypoglycemia awareness 1, 2

   • Patient and family education about prevention, recognition, and treatment is crucial

2. Diabetic ketoacidosis (DKA) risk: Pregnancy is a ketogenic state, and DKA can occur at lower blood glucose levels

   • Prescribe ketone strips and provide education on DKA prevention and detection 1, 2

3. Preeclampsia prevention: Prescribe low-dose aspirin (81 mg/day) from the end of the first trimester until delivery 1, 2

4. Blood pressure targets: 120-160/80-105 mmHg to optimize maternal health and minimize impaired fetal growth 1

5. Retinopathy monitoring: Rapid implementation of tight glycemic control can worsen retinopathy; regular eye exams are recommended each trimester 2

Role of Metformin

While insulin remains the preferred treatment, there is emerging evidence regarding metformin:

• Metformin crosses the placenta, with umbilical cord blood levels equal to or higher than maternal levels 1
• The MiTy trial showed that adding metformin to insulin in women with T2DM resulted in:
  • Better glycemic control
  • Less maternal weight gain
  • Lower insulin requirements
  • Fewer cesarean births
  • However, metformin-exposed infants weighed less and had a higher proportion of small-for-gestational-age babies 3

Postpartum Considerations

• Insulin requirements drop dramatically after delivery of the placenta 1, 2
• Women become very insulin sensitive immediately postpartum and may require much less insulin than during pregnancy
• Return to pre-pregnancy insulin sensitivity occurs over 1-2 weeks 2
• Postpartum screening for persistent diabetes or prediabetes with a 75-g OGTT at 4-12 weeks 1
• Consider metformin for postpartum diabetes prevention in women with previous GDM 4
• Implement a contraceptive plan for all women with diabetes of reproductive potential 1

Pitfalls to Avoid

1. Inadequate monitoring: Frequent blood glucose monitoring and insulin dose adjustments are essential throughout pregnancy due to changing insulin requirements
2. Delayed recognition of DKA: Remember that DKA can occur at lower blood glucose levels during pregnancy
3. Ignoring signs of placental insufficiency: A rapid reduction in insulin requirements in late pregnancy may indicate placental insufficiency and requires immediate evaluation
4. Overlooking hypoglycemia risk: Especially in the first trimester and immediately postpartum
5. Failing to adjust insulin doses postpartum: Insulin requirements decrease by approximately 34% compared to pre-pregnancy levels immediately after delivery 2

By following these guidelines, T2DM can be effectively managed during pregnancy to optimize outcomes for both mother and baby.