SIDS is defined as the sudden death of an infant that is unexpected by history and unexplained by a thorough postmortem examination, which includes a complete autopsy, investigation of the scene of death, and review of the medical history.

An autopsy is essential to identify natural causes of sudden, unexpected death such as congenital anomalies or infection and to diagnose traumatic child abuse.

Although autopsy reveals no pathognomonic findings suggestive or required for the diagnosis, but some common findings are often found. SIDS is the third leading cause of infant mortality in the United States, accounting for 8 per cent of all infant deaths.

Despite the decline in SIDS rates by more than 50 per cent in Canada, the US and many other countries, it continues to be the leading cause of infant death, Currently it accounts for about 25 per cent of all deaths of babies between 1 month and 1 year of age in the West.

The decline in rate is attributed largely to educational campaigns.

The reduction in risk appears to be related primarily to the decrease in placing infants prone (face and tummy on the bed) for sleep and the increase in placing them supine (face upwards).

A number of other risk factors also have significant associations with SIDS — like maternal smoking and alcohol use, intrauterine hypoxia, maternal nutritional deficiency, thermal stress, colder season etc. There are no authentic data on the incidence of SIDS in Indian infants.

There have been studies to show that mutations in cardiac ion channel may put some infants at risk for SIDS.

The actual risk for SIDS in individual infants is also determined by complex interactions between genetic and environmental risk factors.

There appears, for instance, to be an interaction between prone sleep position and impaired respiratory and arousal responsiveness.

No method currently exits to identify future SIDS cases at birth, but it is possible to identify infants at high risk of SIDS based on combinations of established risk factors.

The current challenge is to spread awareness about the condition and the surveillance of SIDS trend in the country.

Dr Anupam Sibal is Senior Consultant, Paediatric Gastroenterology and Hepatology, Indraprastha Apollo, New Delhi

Dr Nishant Wadhwa is Paediatric Gastroenterologist and Hepatologist, Indraprastha Apollo,New Delhi

Sids: The Do’s and Don’ts

• Term and pre-term infants should be placed on their back to sleep. There are no adverse health outcomes from the supine sleeping position. Also, do not place babies on their side.

• Infants should sleep in their own crib or bassinet. Placing the crib or bassinet near the mother’s bed will not hamper breast-feeding and contact. Do not put sleeping babies in a bed or sofa or chair with other children. They should not be brought into bed with parents who are exclusively tired or sedated or inebriated.

• Use a firm mattress for the baby’s bed. Waterbeds, sofas, soft mattresses or other soft surfaces should not be used.

• It is better to avoid keeping soft materials in the infant’s sleep environment. These include pillows, comforters, quilts, sheepskins, cushion-like bumper pads and stuffed toys. Because loose bedding may be hazardous, blankets, if used, should be tucked in around the crib mattress. Sleep clothing, such as a sleep sack, may be used in place of blankets.

• Avoid overheating and over-bundling. The baby should be lightly clothed for sleep and the the mostat set at a comfortable temperature.

• Mothers should not smoke during pregnancy, and babies should not be exposed to secondhand smoke.