Key Findings from Recent Birth Defects and Pediatric Genetics Branch Projects

Pyloric Stenosis Linked to Use of Oral Erythromycin in Newborns

CDC scientists and the Knox County (Tennessee) Health Department investigated a cluster of pyloric stenosis possibly linked to oral erythromycin.

• Pyloric stenosis is a disorder in which a muscle at the bottom of the stomach is enlarged, blocking the outlet of the stomach. It affects 1-3 infants per 1000 live-born infants.
    

• Approximately 90% of babies born in one hospital in Knoxville in February 1999 received oral erythromycin to prevent whooping cough following a whooping cough outbreak among newborn babies born at that hospital. The rate of pyloric stenosis among babies born at this hospital in February 1999 was nearly seven times higher than among babies born there during the previous 2 years.
    

• In a cohort study of infants born in January and February 1999 at the same hospital, approximately 5% (7 of 157) of the newborns who received oral erythromycin developed pyloric stenosis.
    

• The seven babies in this investigation who took erythromycin and developed pyloric stenosis were less than 3 weeks old when they began taking erythromycin; four of them were less than 1 week old when they began erythromycin.
    

• We recommended that physicians use caution when prescribing erythromycin to newborns and that guidelines for the use of erythromycin in newborns be reexamined.

Results published in: Lancet 1999;354:2101-5 (Abstract) and MMWR 1999;48:1117-1120 (Full Text).