Prenatal factors may help predict SIDS risk

Several prenatal factors can be used to help predict the risk of sudden infant death syndrome (SIDS), according to a report in the current issue of the journal Pediatrics.

"There is a very elaborate protocol for assessing postnatal risk factors in the investigation of (sudden infant) deaths, but the assessment of prenatal risk factors is very crude," Dr. Gordon C. S. Smith from Cambridge University in the UK told Reuters Health. "I would see this tool being used in the investigation of these deaths."

Smith and colleagues developed a simple model to predict the risk of SIDS based on obstetric characteristics. In a review of the possible risk factors for SIDS among 252,506 women, the researchers identified significant relationships between the risk for SIDS and the number of children a women has had, the mother's age and her own birthweight, as well as marital status, smoking status and sex of the infant.

A model that incorporated these factors was applied to a population of over 500,000 women and identified 12,387 infants (2.4 percent) who had an elevated risk of SIDS. There were 55 SIDS cases in this group, for an incidence of 44.4 per 10,000.

"Women with a previous SIDS event have an approximately fivefold risk for recurrence compared with the general population," the investigators write. In the UK, these mothers are offered a structured plan for the care of their next infant, which includes keeping a diary of symptoms, using a breathing monitor and scales, and having weekly home visits from a family health specialist.

The researchers say that women at high risk according to their model "might be offered a similar intervention," although additional evaluation of effectiveness and economic feasibility of this service will be needed.

Even in this group, however, "the absolute risk is 0.5 percent," Smith cautioned. Telling a woman that her infant has a high risk of SIDS "would potentially create a great deal of anxiety" and it is not clear that such a screening program will be beneficial.

Smith also pointed out that SIDS "is extremely rare in the majority of the population. Among the 50 percent (with) the lowest predicted risk, i.e., with healthy pregnancies, the incidence was 1 in 10,000."

SOURCE: Pediatrics, January 2006.