Evaluation of penicillin allergy labels in pregnancy reduces beta-lactam alternative antibiotic use in GBS-positive patients.


Penicillin allergy evaluation and subsequent delabeling reduces unnecessary alternative antibiotic use and is safe for pregnant patients, according to new research presented at AAAAI 2026.

“Beta-lactam allergy labels in pregnancy lead to use of alternative antibiotics that are associated with increased risk of adverse outcomes. Therefore, it is important to evaluate methods of beta-lactam allergy testing in pregnancy and their safety. This research suggests that beta-lactam allergy evaluation in pregnancy reduces alternative antibiotic use,” said Divya L. Jasthi, MD, MPH, primary author of the study.

In this single-center retrospective study, researchers examined third trimester pregnant patients referred for penicillin allergy testing from June 2023 to August 2025. To assess methods and outcomes of allergy delabeling, researchers used descriptive analysis and chi-squared analysis to understand the association between testing and alternative antibiotic use.

Among the 111 patients referred for penicillin allergy evaluation, 58 underwent evaluation, 39 of which were through 10/90 challenges, and 19 received penicillin skin testing followed by a full-dose challenge. Only one patient had a positive skin test, while two participants reacted to an amoxicillin challenge despite having a negative skin test. All patients who underwent 10/90 challenges passed, and, among 71 deliveries, 35 patients had penicillin evaluation. Of the 13 GBS-positive patients, only eight underwent penicillin allergy evaluation, leaving five unevaluated. Three patients who did not undergo evaluation received beta-lactam alternative antibiotics during delivery, and researchers noted that an absence of penicillin allergy evaluation was significantly associated with receiving alternative antibiotics in GBS-positive patients (X2 = 6.24,<em> p</em> =0.0125).

The researchers suggested that direct oral challenges in pregnancy should be increasingly considered as penicillin skin testing in the study did not predict reactions in some of the participants. Future study is encouraged toward evaluating outcomes with different testing methodologies to better understand patient care outcomes.