Introduction

Sudden infant death syndrome (SIDS), once known as “cot death”, has been a somewhat controversial term that on one hand has been criticized for not being a proper diagnosis with pathognomonic features, contrasting on the other hand with situations where it has been uncritically and inconsistently applied to all manner of infant deaths. It has been argued that SIDS constitutes a disease with a single cause, an argument which is at odds with those who feel that it is instead a syndrome with common features, and probable heterogeneous and additive risk factors. For this reason it has been called a “diagnosis without a disease” (1). As will be evident from the following chapters, the debate continues.

The term “SIDS” is used when a sleeping infant, who has apparently been quite well, is found unexpectedly dead. Pathological evaluation, including ancillary testing, is unable to discern a cause of death (2-6). Despite the shortcomings of pathology, however, the SIDS story over the past several decades has been one of the great successes in infant healthcare. After specific environmental risk factors were identified in several large studies, awareness campaigns were initiated and promoted by SIDS organizations worldwide, which resulted in death rates from “SIDS” falling dramatically (7-10).

In the Australian context the number of SIDS deaths reduced from over 500 per year in 1988 to 134 per year in 1999 (11), which corresponded to a decrease in the average number of SIDS deaths per 100,000 livebirths from 196 in the 1980s to 52 deaths between 1997 and 2002. In California in the United States, the number of SIDS deaths per year fell from 110.5 deaths per 100,000 live births in 1990 to 47.2 deaths per 100,000 live births in 1998 (4). In more recent years SIDS death rates have levelled, although SIDS is still responsible for a large number of infant deaths globally (12-16).