Outpatient penicillin allergy evaluation during pregnancy and associated clinical outcomes

Beta-lactam antibiotics are often clinically indicated in the peripartum period, posing a challenge for pregnant women who report a penicillin allergy. Allergy verification testing is rarely performed during pregnancy, even though most women do not have a true allergy.

This study aimed to evaluate a hospital-wide multidisciplinary program introduced in August 2020 to identify, refer, evaluate, and test pregnant women with unverified penicillin allergies and assess its association with maternal and neonatal outcomes.

We conducted a retrospective cohort study at a large academic hospital of all pregnant women with a penicillin allergy documented in the electronic medical record who delivered from September 2020 to October 2021. Data were abstracted by medical record review. Women referred for penicillin allergy evaluation were compared with those who were not. Maternal outcomes were alternative antibiotic (clindamycin or vancomycin) use, postpartum infection, and maternal length of postpartum hospital stay. Neonatal outcomes were intensive care unit admission, postnatal blood draw, antibiotic treatment, and birth hospitalization length of hospital stay. Bivariate and multivariable analyses were performed.

Of 689 women with a documented penicillin allergy, 232 (33.7%) were referred for allergy evaluation during the study period. Of those referred, 175 (75.4%) underwent allergy consultation, and of these patients, 167 (95.4%) were considered appropriate for allergy verification testing. Of note, 117 women (70.1%) underwent skin testing with or without graded oral amoxicillin drug challenge, and all but 1 woman (99.1%) were found to be penicillin tolerant. Moreover, 5 additional women were delabeled of their penicillin allergy based on history and pharmacy confirmation of penicillin tolerance subsequent to index reaction. Referred women had a 62% lower likelihood of receiving an alternative antibiotic than those who were not referred, and this significance persisted even after adjusting for potential confounders (adjusted odds ratio, 0.49; 95% confidence interval, 0.27-0.89). Other maternal and neonatal adverse outcomes were less frequent in those referred, but these associations did not reach statistical significance.

This study documented the feasibility, safety, and clinical benefit of an outpatient penicillin allergy referral program for pregnant women. Referred patients were significantly less likely to receive alternative antibiotics; however, more patients are needed to assess whether there are additional clinical benefits.