Severe allergic reactions (anaphylaxisAnaphylaxis A severe allergic reaction that can turn fatal without treatment. Patients with SM are at a higher risk of developing anaphylaxis.) during pregnancy are rare, only affecting about two to three in every 100,000 births. However, women with mast cellMast cell A type of white blood cell produced in the bone marrow. They help defend against infections and play a key role in allergic reactions. In SM, mast cells become overactive and build up throughout the body. disorders such as systemic mastocytosis (SM) are at higher risk, according to a recent review published in The Journal of Allergy and Clinical Immunology: In Practice.
Typical symptoms of anaphylaxis in women with mast cell disorders include widespread redness, flushing, itchy palms and soles, facial swelling, racing heart, dizziness, low blood pressure, nausea, stomach pain, bloating and diarrhea. Anaphylaxis is dangerous for both the mother and the baby.
In mastocytosisMastocytosis Rare disease caused by the buildup of mast cells. Cutaneous mastocytosis primarily affects the skin and is more common in children, while systemic mastocytosis affects internal organs and is more common in adults., there are too many mast cells — cells that cause allergic reactions — in the body. During pregnancy, the uterus naturally fills with more mast cells, raising the risk of anaphylaxis.
Doctors recommend that all pregnant women who have previously had a severe allergic reaction should have a baseline tryptaseTryptase A protein enzyme that is primarily produced by mast cells and stored in small pockets within the cells, known as granules. High levels of tryptase are a key indicator of SM. blood test. This helps identify whether an underlying condition such as a mast cell disorder might be putting them at higher risk.
Certain drugs can also trigger an increase in mast cells and lead to anaphylaxis. “Pregnant women with clonal and nonclonal mast cell disorders should be monitored when exposed to MRGPRX2 binding drugs such as neuromuscular blocking agents, quinolones, vancomycin, and morphine,” the review’s authors said.
The review also recommends that pregnant women with mastocytosis take antihistaminesAntihistamines Medications that block the effects of histamine, the chemical found in mast cells that is responsible for many of the symptoms of SM, as well as many allergic reactions. (both H1 and H2 blockers) before delivery as a precaution. EpinephrineEpinephrine Also called adrenaline, this hormone is used in emergency situations to reverse symptoms during a severe allergic reaction (anaphylaxis). — the first treatment if anaphylaxis happens — is safe during pregnancy.
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In a study of 45 women with mastocytosis described in the review, about one in 10 had a severe allergic reaction during pregnancy, and about one in five found their symptoms got worse, usually in the last three months of pregnancy. In most cases, the severe allergic reactions happened without any obvious trigger.
Just over a third of women in the study were given antihistamines and steroids before delivery as a precaution. Around one in 10 experienced some worsening of symptoms during delivery. Importantly, no mothers or babies died.
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