What are the key practical insights from the new World Health Organization (WHO) guidelines for diabetes and pregnancy?

Key Practical Insights from WHO Guidelines for Diabetes and Pregnancy

Critical Note on Evidence

The provided evidence does not contain the WHO 2024 global guidelines for diabetes and pregnancy referenced in your question. The evidence consists primarily of American Diabetes Association (ADA) Standards of Care (2018-2025) and American College of Obstetricians and Gynecologists (ACOG) recommendations. I will provide key practical insights from these most recent high-quality guidelines, which represent the current standard of care. 1, 2

Preconception Care: The Foundation of Success

Achieve A1C <6.5% before conception to prevent congenital malformations and spontaneous abortion. 2

Medication Management Before Pregnancy

• Immediately discontinue ACE inhibitors, angiotensin receptor blockers, and statins when planning pregnancy, as these are teratogenic 1, 2
• Transition to pregnancy-safe alternatives for blood pressure and lipid control before conception 1
• Initiate folic acid 400-800 mg daily to reduce neural tube defects 1, 2

Essential Preconception Screening

• Comprehensive ophthalmologic examination for retinopathy assessment 1, 2
• Renal function testing (serum creatinine and urine albumin-to-creatinine ratio) 1
• Thyroid function (TSH) screening 1
• ECG for women ≥35 years or those with cardiac symptoms 1
• Use effective contraception until glycemic targets are achieved 2

Glycemic Targets During Pregnancy: Stricter Than Standard Care

The most critical practical change is understanding that pregnancy requires dramatically lower glucose targets than non-pregnant management. 1, 2

Specific Blood Glucose Targets

• Fasting: 70-95 mg/dL (3.9-5.3 mmol/L) 1, 2, 3
• 1-hour postprandial: 110-140 mg/dL (6.1-7.8 mmol/L) OR 1, 2
• 2-hour postprandial: 100-120 mg/dL (5.6-6.7 mmol/L) 1, 2

A1C Targets

• Primary target: <6% (42 mmol/mol) if achievable without significant hypoglycemia 1, 2
• Alternative target: <7% (53 mmol/mol) if hypoglycemia risk is high 1
• A1C is a secondary measure only—self-monitoring of blood glucose is primary 1
• A1C physiologically decreases during pregnancy due to increased red blood cell turnover, making it less reliable 1

Monitoring Strategy: Postprandial Focus

Postprandial glucose monitoring is superior to preprandial monitoring alone and reduces preeclampsia risk. 1, 2

Practical Monitoring Protocol

• Check blood glucose 4-7 times daily: fasting, preprandial, and 1-2 hours postprandial 3
• Preprandial testing is essential for adjusting rapid-acting insulin doses with basal-bolus therapy 1
• Continuous glucose monitoring (CGM) is an adjunct, NOT a replacement for self-monitoring 1, 2
• CGM reduces large-for-gestational-age births and neonatal hypoglycemia in type 1 diabetes 1, 2
• Do NOT use estimated A1C or glucose management indicator calculations from CGM during pregnancy—they are inaccurate 1

Insulin Management: The Gold Standard

Insulin is the preferred first-line medication for all types of diabetes during pregnancy. 1, 2, 4

Insulin Physiology Changes During Pregnancy

• First trimester (weeks 0-16): Enhanced insulin sensitivity, DECREASED insulin requirements, increased hypoglycemia risk 1
• Second/third trimester (weeks 16-36): Progressive insulin resistance, insulin requirements typically DOUBLE by week 36 1
• Immediately postpartum: Dramatic DROP in insulin requirements after placental delivery—rapid dose reduction essential to prevent hypoglycemia 1, 2

Practical Insulin Dosing Algorithm

• Early pregnancy: Decrease basal rates by 10-30% from preconception doses 3
• Mid-to-late pregnancy: Increase insulin by approximately 5% weekly to match rising insulin resistance 3
• Sudden decrease in insulin requirements: May indicate placental insufficiency—requires immediate evaluation 1

Hypoglycemia Education is Mandatory

• Educate patient AND family members on recognition, prevention, and treatment of hypoglycemia 1, 2
• Women with type 1 diabetes have altered counterregulatory response during pregnancy, decreasing hypoglycemia awareness 1
• Ketone strips must be provided for home use—pregnancy is a ketogenic state with diabetic ketoacidosis risk at lower glucose levels than non-pregnant state 1

Gestational Diabetes Management

Initial treatment is medical nutrition therapy and exercise for 1-2 weeks; if targets not met, initiate insulin. 2

Treatment Algorithm

• Start with consistent carbohydrate intake matched to activity level 1, 2
• Limit processed foods, fatty red meat, and sweetened beverages 1
• If glucose targets not achieved within 1-2 weeks, start insulin 2
• Metformin crosses the placenta with higher umbilical cord levels than maternal levels 1, 5
• Long-term offspring outcomes with metformin are unknown—patients must be informed 1, 5

Preeclampsia Prevention

Prescribe low-dose aspirin 60-150 mg daily (typically 81 mg) from end of first trimester until delivery. 1

• Diabetes significantly increases preeclampsia risk 1
• Aspirin should be started after 12 weeks gestation 1

Retinopathy Monitoring

Rapid implementation of tight glycemic control in women with existing retinopathy can worsen retinopathy. 1

• Comprehensive ophthalmologic examination at baseline 2
• Close monitoring throughout pregnancy for progression 1
• Treatment if indicated during pregnancy 1

Common Pitfalls to Avoid

Insufficient Insulin Dose Escalation

• Failure to increase insulin adequately in second/third trimester leads to hyperglycemia and fetal complications 3
• Insulin requirements typically double by week 36—anticipate this 1

Over-Reliance on A1C

• A1C does not capture postprandial hyperglycemia, which drives macrosomia 1
• Self-monitoring of blood glucose is the primary tool 1, 2

Fear of Hypoglycemia Leading to Inadequate Control

• While hypoglycemia risk is real, inadequate glycemic control causes greater fetal harm 3
• Balance is achieved through frequent monitoring and patient education, not by accepting higher glucose targets 2

Ignoring Carbohydrate Consistency

• Inconsistent carbohydrate intake makes insulin dosing nearly impossible 3
• Women with diabetes must eat consistent carbohydrate amounts to match insulin administration 1

Postpartum Management

Insulin requirements drop dramatically immediately after placental delivery—rapid dose reduction is essential. 1, 2

• Women become extremely insulin sensitive postpartum 1
• May initially require much less insulin than prepartum period 1
• Women with gestational diabetes require postpartum screening for persistent diabetes at 4-12 weeks using 75-g oral glucose tolerance test 1
• Good glucose control supports lactation 4