Contents: Clinical Expert SeriesPenicillin Allergy in Pregnancy Moving From “Rash” Decisions to Accurate DiagnosisTurrentine, Mark A. MD; King, Tekoa L. CNM, MPH; Silverman, Neil S. MDAuthor Information Department of Obstetrics and Gynecology, Baylor College of Medicine, Houston, Texas; and the School of Nursing, University of California at San Francisco, San Francisco, and the Center for Fetal Medicine and Women's Ultrasound, Department of Obstetrics and Gynecology, David Geffen School of Medicine at the University of California, Los Angeles, Los Angeles, California. Corresponding author: Mark A. Turrentine, MD, Department of Obstetrics and Gynecology, Baylor College of Medicine, Houston, TX; email: [email protected]. Financial Disclosure The authors did not report any potential conflicts of interest. Each author has indicated that he or she has met the journal's requirements for authorship. Peer reviews and author correspondence are available at http://links.lww.com/AOG/B686. Obstetrics & Gynecology: February 2020 - Volume 135 - Issue 2 - p 401-408 doi: 10.1097/AOG.0000000000003662 Buy Metrics AbstractIn Brief The emergence of beta-lactam–resistant pathogenic organisms has resulted in limitation or even elimination of drugs such as penicillin and ampicillin from available antibiotic choices for treating common infections in obstetrics and gynecology. In clinical situations for which penicillins and cephalosporins are appropriate or recommended first-line agents, the problem of patient-reported penicillin allergies has led to routine use of alternative but potentially less effective agents. The use of broader-spectrum and potentially suboptimal alternative antibiotic regimens for intrapartum antibiotic prophylaxis against group B streptococcus or for surgical prophylaxis for cesarean delivery in women with a reported penicillin allergy may affect these women during labor and birth. Most individuals who report a penicillin allergy are neither truly allergic nor at risk of developing a hypersensitivity reaction after exposure to penicillin. The available evidence suggests that there are important roles for both targeted history-taking, to determine the nature of drug allergies and penicillin allergy testing in pregnant women, to optimize their antibiotic-related treatment both during pregnancy and for their lifetimes. Wider consideration and adoption of penicillin allergy testing in pregnant women specifically, as well as the general population of women cared for by providers of obstetrics and gynecology, is recommended. Pregnant women with a history of a penicillin allergy with an unknown or immunoglobulin E–mediated reaction would benefit from penicillin allergy testing. © 2020 by the American College of Obstetricians and Gynecologists. Published by Wolters Kluwer Health, Inc. All rights reserved.