Predicting SIDS

Maternal levels of a certain protein during the second trimester of pregnancy may help predict which infants are at greatest risk for sudden infant death syndrome.

That’s the key finding from a study out of Scotland that compared maternal blood levels of alpha-fetoprotein with infant deaths and other factors. Results showed women with the highest levels of the protein were nearly three-times as likely to have a baby that died of SIDS than those with the lowest levels.

The researchers conducted the study because higher levels of alpha-fetoprotein during the second trimester of pregnancy have been associated with a greater likelihood of stillbirth. Since babies who are stillborn have traits in common with infants who succumb to SIDS — such as reduced fetal growth — they wondered if higher levels might predict SIDS as well.

The study is based on medical records from more than 200,000 women who gave birth in Scotland. There were 114 cases of SIDS among the newborns.

The researchers note public health campaigns aimed at getting new parents to place their babies on their backs to sleep and refrain from exposing them to secondhand tobacco smoke have made a big dent in the number of infants dying from SIDS in recent years. Still, some infants continue to die from SIDS. They believe these findings may help explain why these deaths still take place.

“The observed association between elevated maternal serum alpha-fetoprotein levels during the second trimester and the incidence of SIDS suggests that an adverse intrauterine environment during the first half of pregnancy may be another important determinant of the risk of SIDS,” they write.

SOURCE: The New England Journal of Medicine, 2004;351:978-986