What causes SIDS?

As the name implies, SIDS is the sudden and unexplained death of an infant who is younger than 1 year old. It is a frightening prospect because it can strike without warning, usually in a seemingly healthy infant. Most SIDS deaths are associated with sleep (hence the common reference to "crib death"), and infants who die of SIDS show no signs of suffering. - KidsHealth

Professor B. Knight says: “It now seems obvious that there is no single cause of cot death." Therefore, several factors combined, may be the cause of death. Some known factors are: young maternal age at birth, retarded growth of development, low birth weight, and maternal smoking. Another factor, such as Hemoglobin F, can cause serve as a useful marker for those babies at risk.

What can be done?

Unfortunately, we cannot expect to prevent all SIDS deaths now. To do so requires a much greater understanding of SIDS, which will be achieved only with a commitment from those who value babies and with a considerably expanded research effort.

However, there are things that can be done to reduce the risk of SIDS. Get medical care early in pregnancy, preferably within the first three months, followed by regular checkups at the doctor's office or health clinic. Make every effort to assure good nutrition. These measures can reduce the risk of premature birth, a major risk factor for SIDS. – American Sids Institute