Most SIDS deaths occur when babies are between two months and four months old.

Although 90 percent of SIDS deaths occur by six months of age, older infants can die spontaneously and unexpectedly as well.

Most SIDS deaths happen when babies are between 2 months and 4 months of age.

In other words, the SIDS deaths would have occurred even if no vaccinations had been given.

Those guidelines weren't out when the SIDS deaths in Li's study occurred.

That advice is credited with a drop in SIDS deaths, writes Li.

First, Meadow's calculation was based on the assumption that two SIDS deaths in the same family are independent of each other.

A SIDS death happens while a baby is asleep.

Premature birth - increases risk of SIDS death roughly fourfold.

This has led some researchers to estimate that 5% to 20% of SIDS deaths are actually infanticides.