What three factors must align according to the Triple-Risk Model for SIDS?

A vulnerable infant, a critical developmental period, and an outside stressor.

The Triple-Risk Model posits that SIDS results from the simultaneous convergence of three distinct elements. The first element is the vulnerable infant, suggesting an underlying biological predisposition, possibly subtle abnormalities in the brain stem circuits controlling vital functions like arousal and breathing. The second element is the critical developmental period, often identified as the time when the infant's respiratory and cardiac control systems are rapidly maturing, frequently occurring between two and four months of age. The third element is the external stressor, which acts as an environmental factor that overwhelms the fragile control systems of the infant, such as sleeping in the prone position or experiencing overheating.