Bottle feeding associated with increased risk of infant stomach obstruction

HPS typically occurs during an infant's first two months of life and surgery is needed to correct the obstruction, which occurs because of a thickening of the smooth muscle layer of the pylorus (the passage between the stomach and small intestines). Despite how frequently the condition occurs (about 2 cases per 1,000 births), its cause remains unknown, the authors write in the study background.

Jarod P. McAteer, M.D., M.P.H., of the Seattle Children's Hospital, and colleagues used Washington state birth certificates and discharge data to examine births between 2003 and 2009. The study included 714 infants admitted with HPS who had a procedure code for HPS surgery (pyloromyotomy). Study controls were infants without HPS. Breastfeeding status was recorded on Washington state birth certificates for all infants during the study period.

The findings indicate that that the incidence of HPS decreased from 14 per 10,000 births in 2003 to 9 per 10,000 births in 2009. Breastfeeding prevalence increased during that time from 80 percent in 2003 to 94 percent in 2009. Infants who developed HPS were more likely to be bottle fed compared with controls (19.5 percent vs. 9.1 percent). The odds of an infant developing HPS also increased when mothers were 35 years and older and multiparous (having given birth more than once).

"These data suggest that bottle feeding may play a role in HPS etiology, and further investigations may help to elucidate the mechanisms underlying the observed effect modification by age and parity," the study concludes.