How is mast cell activation syndrome (MCAS) managed during pregnancy?

Management of Mast Cell Activation Syndrome During Pregnancy

Management of mast cell activation syndrome (MCAS) during pregnancy requires a multidisciplinary approach focused on trigger avoidance, prophylactic antihistamine use, as-needed corticosteroids, and epinephrine availability for anaphylaxis to minimize maternal and fetal risks. 1

Core Management Strategy

First-Line Approaches

• Multidisciplinary team management involving high-risk obstetrics, anesthesia, and allergy specialists during preconception, pregnancy, and peripartum period 1
• Trigger avoidance as the cornerstone of management 1
  • Identify and avoid individual triggers (foods, medications, temperature extremes, stress)
  • Pain management is critical as pain can trigger mast cell activation 1

Pharmacological Management

• H1 and H2 antihistamines as primary prophylactic therapy 1
  • Examples: cetirizine, fexofenadine (H1); famotidine, ranitidine (H2)
  • Titrate to minimize potential harm to fetus while controlling symptoms
• Corticosteroids for acute symptom flares or as needed 1
• Epinephrine auto-injector must be available at all times for anaphylaxis 1
• Anxiolytic agents (benzodiazepines) may be considered for severe anxiety that could trigger mast cell activation 1

Special Considerations

Peripartum Management

• Anesthetic considerations:
  • Safer anesthetic agents include propofol, sevoflurane, isoflurane 1
  • Safer analgesics include fentanyl, remifentanil 1
  • Safer local anesthetics include lidocaine, bupivacaine 1
  • Avoid muscle relaxants atracurium and mivacurium; use rocuronium or vecuronium if needed 1
  • Exercise caution with opioids like codeine or morphine 1

Management of Severe/Refractory Cases

• For severe cases unresponsive to conventional therapy, interferon-alfa may be considered 1
• Avoid cytoreductive therapies such as cladribine, imatinib, and midostaurin during pregnancy 1

Anaphylaxis Management

• Immediate intervention with:
  • Discontinuation of suspected trigger
  • Fluid resuscitation
  • Intravenous epinephrine for severe reactions
  • Corticosteroids and antihistamines as adjuncts 1
• Post-reaction workup:
  • Serum tryptase level within 30-120 minutes of symptom onset
  • Baseline tryptase after recovery for comparison 1

Monitoring and Outcomes

• Regular assessment of MCAS symptoms throughout pregnancy

• Potential complications to monitor:

  • Spontaneous miscarriages reported in 20-30% of pregnant women with mastocytosis 1
  • Symptoms related to mast cell mediator release observed in 11% of patients 1
  • Increased risk of preterm delivery in later stages of pregnancy 1

• Breastfeeding considerations: Consult with pediatrician and lactation consultant regarding medication safety during lactation 1

Important Caveats

• MCAS is not a contraindication to successful pregnancy, but requires vigilant management 1
• Limited evidence exists regarding impact of MCAS on pregnancy outcomes compared to general population 1, 2
• Early identification and control of MCAS prior to pregnancy is optimal for reducing complications 2
• Risk of anaphylaxis in perioperative period is higher in patients with mast cell disorders 1