Penicillin allergy evaluation in pregnancy: Safety, efficacy, and antibiotic use outcomes

Objective: Penicillin allergy (PA) is associated with an increased risk for cesarean delivery, prolonged postpartum hospital stay, and less-preferred antibiotic prophylaxis and treatment. However, the majority of pregnant women with PA can safely receive penicillin after an allergy evaluation. We aimed to evaluate the safety and efficacy of PA delabeling across all trimesters and to characterize rates of first-line Group B Streptococcus (GBS) prophylaxis after PA delabeling. Methods: We conducted a retrospective analysis of clinical visits for pregnant women with PA referred to Duke Allergy and Immunology Clinic from October 2023 through May 2025. Outcome measures included removal of the PA label and subsequent peripartum antibiotic use. Results: Of the 117 pregnant patients with PA evaluated in the Allergy and Immunology clinic, 112 (96%) underwent PA testing, with gestational age spanning all trimesters. Two patients (2%) had direct oral challenge, which was tolerated without adverse reaction. The other 110 patients (98%) had skin testing, of which 106 (96%) were negative. Of these, 101 women (95%) subsequently passed oral amoxicillin challenge. All patients with negative testing results were delabeled. Among these, 30 women required GBS prophylaxis. Yet, 10 women (33%) received a penicillin alternative or no antibiotics. In total, 18 women were delabeled and reexposed to intrapartum penicillin. None had adverse reactions. Conclusion: PA evaluation is likely safe and effective through all trimesters of pregnancy. Further research, including randomized controlled trials, are needed to expand this knowledge. Most pregnant women referred for PA evaluation can have PA delabeled. Surprisingly, a large portion of women did not receive first-line GBS prophylaxis despite PA removal, reiterating the need for improved interdisciplinary communication.