Safety and outcomes of penicillin allergy evaluation in pregnant women

Background: Penicillin allergy in pregnancy is associated with increased morbidity and the use of less effective antibiotics. Penicillin allergy evaluation in pregnancy is now recommended as per obstetrical guidelines but remains infrequent.

Objective: We studied pregnant women who underwent penicillin allergy evaluation in an allergy clinic to assess the effectiveness and safety of penicillin skin testing (PST) and incremental drug challenge (IDC) in pregnancy.

Methods: Index drug reactions, PST, and IDC results were reviewed. Antibiotic use, pregnancy outcomes, and pregnancy complications were compared with a control cohort of pregnant women with penicillin allergy who did not undergo allergy evaluation before delivery.

Results: Penicillin allergy was evaluated in 136 women. Culprit drugs included penicillin (37%), amoxicillin (30%), and unknown (20%). Index reactions occurred greater than 5 years ago in 91%, and these reactions were cutaneous or unknown in 92%. Of the 133 patients who underwent skin testing, 131 (99%) had negative or equivocal results and proceeded to incremental challenge. All 131 women passed penicillin IDC. Of the 69 women who ultimately used intrapartum beta-lactam antibiotics, all but 1 patient tolerated them. Women who underwent penicillin allergy evaluation did not have an increased risk of cesarean delivery or other pregnancy complications when compared with women without penicillin allergy evaluation.

Conclusion: PST and IDC can be safely conducted in pregnant women. When evaluated as low risk, most women tolerate IDC and can receive penicillin intrapartum without adverse reactions or negative pregnancy outcomes.