The Mechanism of SIDS

1/06/2010

Although much research has been carried out over the past twenty years into the mechanism of SIDS, no definitive cause has been identified. Perinatal risk factors such as premature birth, low birth weight, being one of a multiple pregnancy or being exposed to maternal smoking in utero have all been identified as significant risk factors for SIDS. Environmental risk factors such as prone sleeping position, infant overheating or overcooling, and ambient room temperatures above 24°C, have also been identified. In addition, social factors such as infants born to teenage mothers, young and unsupported mothers, and mothers of low socioeconomic status, increase the risk for SIDS.

Currently, many researchers investigating the mechanism of SIDS believe that an infant dies only when a number of factors occur simultaneously. This hypothesis encompasses both epidemiological and scientific data on SIDS. It is also well documented that the incidence of SIDS peaks between 2 – 4 months of age. During this period, major changes are occurring in virtually all physiological systems, as infants attain adaptive mechanisms, enabling them to maintain homeostasis (balance). These include automatic control of ventilation, sleep/wake state organisation, temperature regulation and development of circadian rhythms. If during this critical period the “at risk” infant is also exposed to an external stressor, such as a respiratory tract or gastrointestinal infection, fever, the prone sleeping position, or hypothermia due to over wrapping, then the threshold for SIDS may be reached (Filiano & Kenny 1994).