AMERICAN JOURNAL OF INDUSTRIAL MEDICINE 54:118–127 (2011) Exposure to Anesthetic Gases and Congenital Anomalies in Offspring of Female Registered Nurses Kay Teschke, MPH, PhD, 1,2 Zenaida Abanto, MSc, 3 Laura Arbour, MD, 4 Kris Beking, BSc, 5 Yat Chow, MSc, 2 Richard P. Gallagher, MA, 6 Ben Jong, BSc, 5 Nhu D. Le, PhD, 6 Pamela A. Ratner, PhD, 3 John J. Spinelli, PhD, 6 and Helen Dimich-Ward, PhD 5 Background Studies of offspring of mothers exposed to anesthetic gases have shown associations with congenital anomalies reported by the mothers, but rarely in studies with objectively ascertained outcomes. We conducted a retrospective cohort study to examine associations between registry-ascertained congenital anomalies in offspring and anesthetic gas exposure of mothers employed as nurses. Methods A cohort of registered nurses in British Columbia, Canada, was linked to records of births and congenital anomalies from 1990 to 2000. Exposures were assessed via a survey of anesthetic gas use in all hospitals in the province and records of nurses’ jobs, departments, and hospitals. Results Departments most frequently reporting anesthetic gas use were operating rooms, post-anesthetic recovery rooms, and maternity units. In the cohort of 15,317 live-borne children of 9,433 mothers, 1,079 had congenital anomalies. Anomalies were associated with ever and probable maternal exposure to halogenated gases (ORs: 1.49, 95% CI: 1.04–2.13; and 2.61, 95% CI: 1.31–5.18, respectively) and to nitrous oxide (ORs: 1.42, 95% CI: 1.05–1.94; and 1.82, 95% CI: 1.11–2.99). Anomalies most frequently associated with exposure were those of the heart (OR, halogenated gases: 2.31, 95% CI: 1.07–4.97) and integument (OR, halogenated gases: 3.56, 95% CI: 1.53–8.32; OR, nitrous oxide: 3.02, 95% CI: 1.37–6.64). Gases most frequently associated with anomalies were halothane (predominantly used early in the study period), isoflurane, and sevoflurane (predominantly used later in the period). Conclusions In this study, where both exposures and outcomes were assessed objectively, certain congenital anomalies were associated with estimated anesthetic gas exposure. Am. J. Ind. Med. 54:118–127, 2011. ß 2010 Wiley-Liss, Inc. KEY WORDS: anesthetics; inhalation; congenital abnormalities; maternal exposure; occupational health nursing ß 2010 Wiley-Liss, Inc. *Correspondence to: Dr. KayTeschke, School of Population and Public Health, 2206 East Mall, University of British Columbia,Vancouver, CanadaV6T1Z3. E-mail: kay.teschke@ubc.ca Accepted 28 May 2010 DOI 10.1002/ajim.20875. Published online 6 July 2010 in Wiley InterScience (www.interscience.wiley.com) 1 School of Population and Public Health,Universityof British Columbia,Vancouver,Canada 2 School of Environmental Health, University of British Columbia,Vancouver, Canada 3 School of Nursing, University of British Columbia,Vancouver, Canada 4 Department of Medical Genetics, University of British Columbia,Vancouver, Canada 5 Department of Medicine, University of British Columbia,Vancouver, Canada 6 BC Cancer Research Centre,Vancouver, Canada Contract grant sponsor: WorkSafeBC; Contract grant number: RS2000/01-015; Contract grant sponsor: Canadian Institutes of Health Research; Contract grant number: 135329.