ArticlesSimultaneous Sudden Infant Death Syndrome: A Proposed Definition and Worldwide Review of CasesKoehler, Steven A. Ph.D; Ladham, Shaun M.D; Shakir, Abdulrezzak M.D; Wecht, Cyril H. M.D., J.DAuthor Information From the Graduate Program of Forensic Epidemiology (S.A.K.) and the Graduate School of Public Health, University of Pittsburgh; the Allegheny County Coroner’s Office, Forensic Pathology Laboratory (S.L., A.S.); and the Allegheny County Coroner’s Office (C.H.W), Pittsburgh, Pennsylvania. Manuscript received January 20, 1999; revised January 25, 2000; accepted May 19, 2000. Address correspondence and reprints to S. A. Koehler, Ph.D., Allegheny County Coroner’s Office, 542 Fourth Avenue, Pittsburgh, PA 15219, U.S.A. The American Journal of Forensic Medicine and Pathology: March 2001 - Volume 22 - Issue 1 - p 23-32 Buy Abstract Epidemiologic studies of sudden infant death syndrome (SIDS), the leading cause of death of infants during the postperinatal period (7–365 days), have mainly focused on the deaths of single infants. Simultaneous sudden infant death syndrome (SSIDS), the death of a pair of twins occurring at the same time, has received limited attention within the medical community. To the authors’ knowledge, this article is the first to describe the 41 SSIDS cases cited in the world literature from 1900 to 1998 by the location of death, a summary of the circumstances surrounding the deaths, and evaluation of these cases in terms of a proposed definition of SSIDS. This evaluation critiques whether the 41 pairs of SSIDS cases adhere to a newly proposed definition of SSIDS. Twin infant deaths must meet all three criteria to be considered SSIDS. The study found that only 12 pairs of twins met all three criteria (29.2%), nine pairs met two criteria (21.9%), alternative cause of death was offered in five pairs of twins (12.1%) and in the remaining 15 pairs (36.6%), only limited information was available; therefore, no conclusions could be reached. © 2001 Lippincott Williams & Wilkins, Inc.