Bottles up risk for hypertrophic pyloric stenosis

It seems that bottlefeeding, compared with breastfeeding, more than doubles the risk for hypertrophic pyloric stenosis (HPS) in children, and that HPS is more common among children born to women who are older and multiparous, according to the largest study to date on the topic.

Researchers conducted a population-based study of singleton infants born in Washington State between 2003 and 2009. To be included in the research, the infants had to be aged younger than 6 months, diagnosed with HPS, and have received corrective surgery for the condition.

Using birth certificates and hospital discharge data, the investigators found that 19.5% of those children who were bottlefed developed HPS compared with 9.1% of those who were breastfed.

Although the association was unaffected by sex or maternal smoking status, it was significantly modified by maternal age and parity. Children born to mothers who were at least 35 years of age had about 6 times the risk of HPS as those born to mothers aged younger than 20 years. Those born to multiparous mothers had about twice the risk of those born to nulliparous moms.

The study also revealed that the incidence of HPS decreased over time, from 14 per 10,000 births in 2003 to 9 per 10,000 births in 2009. The investigators also found that the prevalence of breastfeeding increased over time, from 80% in 2003 to 94% in 2009.

The researchers are unsure of the mechanisms behind the associations.

The prevalence of HPS is generally reported to be somewhere between 2 and 4 per 1,000 live births, with greater prevalence among males than females and among white children than among Hispanics, Blacks, or Asians. 

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