Aspirin Desensitization Safe in Pregnancy With NSAID Allergy

TOPLINE:

Aspirin desensitization protocol enables 94.1% of pregnant women with nonsteroidal anti-inflammatory drug (NSAID) hypersensitivity to tolerate daily aspirin for preeclampsia prevention. Among 28 completed pregnancies, preeclampsia occurred in 14.3% of cases at a median gestational age of 37 weeks.

METHODOLOGY:

• A cross-sectional study enrolled 34 pregnant women with moderate to high-risk factors for preeclampsia and self-reported nonsteroidal anti-inflammatory drug hypersensitivity between January 2021 and November 2024.
• Participants underwent supervised desensitization in outpatient allergy clinics, receiving sequential oral aspirin doses (1 mg, 2 mg, 4 mg, 8 mg, 16 mg, 32 mg, 37 mg, and 50 mg) at 20-minute intervals to reach final doses of 100 mg or 150 mg.
• Researchers monitored maternal blood pressure, pulse rate, and oxygen saturation after each dose, with continued observation for 1 hour post-final dose to assess adverse reactions and uterine contractions.

TAKEAWAY:

• Of the 34 participants, 16 (47.1%) developed periorbital angioedema, with seven (20.6%) reacting to 100 mg cumulative aspirin dose and nine (26.5%) to 150 mg dose.
• All mucocutaneous reactions were mild and manageable with antihistamines, with no episodes of anaphylaxis, bronchial symptoms, or serious adverse events requiring epinephrine or hospitalization.
• Among the 32 (94.1%) women who continued daily aspirin post-desensitization, 17 (53.1%) received 150-mg doses, while 15 (46.9%) received 100-mg doses.
• In the 28 completed pregnancies, all resulted in live births with preeclampsia occurring in four (14.3%) cases at a median gestational age of 37 weeks (interquartile range, 36.6-37.2).

IN PRACTICE:

“While angioedema as an initial reaction to NSAIDs is a recognized risk factor for aspirin desensitization failure in nonpregnant adults, our series found that pregnant individuals exhibited only mild, antihistamine-responsive symptoms during desensitization, which did not prevent the continued use of aspirin until 36 weeks’ gestation. We speculate that one possible explanation is the physiological decline in interleukin-4 (IL-4) levels during pregnancy, which might reduce the IL-4–dependent expression of proinflammatory cysteinyl-leukotrienes, namely leukotriene C4, thus facilitating a favorable response to desensitization and subsequent tolerance to aspirin in the antenatal period,” wrote the authors of the study.

SOURCE:

The study was led by Pradip Dashraath, MRCOG, Department of Obstetrics and Gynaecology, Division of Maternal-Fetal Medicine, National University Hospital in Singapore. It was published online in American Journal of Obstetrics and Gynecology.

LIMITATIONS:

According to the authors, the study was limited by a small sample size and the absence of a control group. The researchers note that these preliminary results need validation through a prospective, multinational study to account for geographic and genotypic variations in allergy phenotypes.

DISCLOSURES:

The study was funded by the National University Health System Seed Fund (NUHSRO/2021/105/RO5+6/Seed-Sep/08) and approved by the National Healthcare Group Domain Specific Review Board, Singapore. The authors reported no competing interests.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.