What is the recommended approach to managing a high-risk pregnancy with pre-existing medical conditions?

Managing High-Risk Pregnancy with Pre-Existing Medical Conditions

Women with pre-existing medical conditions planning pregnancy should achieve disease quiescence or optimal control before conception, transition to pregnancy-compatible medications, and be co-managed by a multidisciplinary team including specialists in their specific condition alongside maternal-fetal medicine. 1

Pre-Conception Optimization

Disease control before pregnancy is paramount - entering pregnancy with active or poorly controlled disease significantly increases maternal and fetal complications across all conditions. 1

Essential Pre-Pregnancy Steps:

• Achieve disease remission or low activity for at least several months before attempting conception, as this dramatically improves outcomes for both mother and baby 1
• Switch all teratogenic medications to pregnancy-compatible alternatives and observe for adequate efficacy before conception - this includes discontinuing ACE inhibitors, angiotensin receptor blockers, statins, warfarin, and most category D/X medications 1
• Optimize glycemic control in diabetic women to A1C <6.5% (48 mmol/mol) if achievable without significant hypoglycemia, as this minimizes risk of congenital anomalies, preeclampsia, and preterm birth 1
• Assess organ function including renal function (creatinine, urinary albumin-to-creatinine ratio), cardiac function (echocardiography for cardiac conditions), and liver function as indicated 1

Contraindications to Pregnancy:

Pregnancy should be strongly discouraged or contraindicated in women with: 1

• Pulmonary arterial hypertension (maternal mortality 20-50%) 1
• Severe left ventricular outflow tract obstruction 1
• Eisenmenger syndrome with oxygen saturation <85% 1
• Severe heart failure or significant cardiac damage 1
• Treatment-requiring overt myelofibrosis 1

Condition-Specific Management During Pregnancy

Cardiovascular Disease:

• Continue beta-blockers throughout pregnancy for conditions like Marfan syndrome with aortic root involvement 1
• Perform serial echocardiograms before, during, and after pregnancy for inherited aortic conditions 1
• Plan delivery mode early: cesarean section reserved for aortic roots >4.5 cm or delayed second stage; vaginal delivery preferred for most others 1
• Avoid vasopressors unless hypotension is intractable and unresponsive to fluid resuscitation, as they adversely affect uteroplacental perfusion 2

Diabetes Mellitus:

• Maintain tight glycemic control with fasting glucose <95 mg/dL (5.3 mmol/L) and 1-hour postprandial <140 mg/dL (7.8 mmol/L) 1
• Target A1C <6% (42 mmol/mol) during pregnancy if achievable without significant hypoglycemia; may relax to <7% (53 mmol/mol) if needed 1
• Use continuous glucose monitoring in addition to self-monitoring to reduce macrosomia and neonatal hypoglycemia, particularly in type 1 diabetes 1
• Metformin is compatible with pregnancy - limited data show no clear association with major birth defects or miscarriage, though poorly controlled diabetes itself increases risks substantially 3

Rheumatic and Autoimmune Diseases:

• Continue hydroxychloroquine in SLE patients throughout pregnancy 1
• Start low-dose aspirin in antiphospholipid antibody-positive patients 1
• Add prophylactic heparin for obstetric antiphospholipid syndrome; therapeutic heparin for thrombotic antiphospholipid syndrome 1
• Monitor disease activity with laboratory assessment at least once per trimester 1
• Perform serial fetal echocardiography weeks 16-26 in anti-Ro/La positive patients due to risk of congenital heart block 1

Liver Disease:

• Plan delivery at 35-36 weeks for intrahepatic cholestasis with bile acids ≥100 μmol/L due to sudden fetal demise risk 1
• Delay delivery until ≥37 weeks for lower bile acid levels 1
• Deliver at 38-39 weeks for most pre-existing liver disorders 1
• Prepare for hemorrhage risk in portal hypertension, cirrhosis, HELLP syndrome, or acute fatty liver - ensure cross-matched blood products and IV access 1

Myeloproliferative Neoplasms:

• Administer aspirin to all JAK2-mutated essential thrombocythemia patients or those with cardiovascular risk factors 1
• Maintain hematocrit <45% with phlebotomy in polycythemia vera 1
• Use interferon-alpha (pegylated 45 mcg subcutaneously weekly) for high-risk patients or those with recurrent fetal loss 1
• Prescribe therapeutic LMWH for patients with prior venous thrombosis 1

Monitoring and Delivery Planning

Frequency of Visits:

• Low-risk patients with well-controlled conditions can be managed locally with specialist consultation available 1
• Higher-risk patients require management at or from a tertiary cardiac/specialty center 1
• Highest-risk patients need admission from approximately 20 weeks gestation 1

Delivery Considerations:

• Vaginal delivery is preferred for most conditions unless specific contraindications exist 1
• Epidural anesthesia is favored but avoid excessive vasodilatation in cyanotic patients or those with fixed stroke output 1
• Regional anesthesia may be contraindicated by maternal thrombocytopenia or coagulopathy, requiring general anesthesia for cesarean or systemic opiates for vaginal delivery 1
• Antibiotic prophylaxis is discretionary for most cardiac conditions during delivery 1

Critical Pitfalls to Avoid:

• Never defer indicated radiographic studies including CT scans due to fetal radiation concerns - maternal assessment takes priority 2
• Do not use diagnostic ultrasound to rule out placental abruption in trauma - it lacks sensitivity and management should not be delayed 2
• Avoid supine positioning after mid-pregnancy - manually displace uterus or use left lateral tilt to prevent inferior vena cava compression 2
• Do not inflate abdominal portion of military anti-shock trousers as this reduces placental perfusion 2

Postpartum Management

• Monitor closely for 24 hours after delivery due to significant hemodynamic changes and fluid shifts 4
• Risk of thromboembolism peaks in the postpartum period, particularly in myeloproliferative neoplasms where blood counts normalize within 4-6 weeks 1
• Breastfeeding considerations: metformin is present in breast milk at low levels (0.11-1% of maternal weight-adjusted dose) with milk/plasma ratio 0.13-1.0 3
• Postpartum hemorrhage risk is elevated in conditions causing coagulopathy, thrombocytopenia, or portal hypertension 1