Descriptive Epidemiology of infantile hypertrophic pyloric stenosis in United States Open Access

Renuka, Renuka (2017)

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Background: Infantile hypertrophic pyloric stenosis, commonly referred to as pyloric stenosis (PS) is characterized by muscular hypertrophy of the pyloric sphincter, causing obstruction of the gastric outlet in the newborns. The epidemiology and etiology of PS is not well-understood, with previous reports differing on prevalence estimates and characteristics associated with PS. The aim of this study was to conduct a comprehensive, population-based investigation of descriptive epidemiology of PS in the United States (U.S.).

Methods: Population-based data for cases with PS (n=16,320), delivered during 1999-2005 and enumerated from 11 U.S. birth defects surveillance programs, along with data for all live births (n=8,390,584) within the same time period and catchment areas were used to estimate PS prevalence and associations with selected infant and parental characteristics. Adjusted prevalence odds ratios (aPORs) and 95% confidence intervals (CIs) were estimated using multivariable logistic regression analyses for all cases combined and for isolated cases (without other major birth defects).

Results: The prevalence (per 10,000 live births) for all PS cases combined (n=16,320) was 19.45 (95% CI=19.15, 19.75); the prevalence for isolated cases (n=14,548; 89% of total) was 17.33. After adjusting for selected infant and parental characteristics, male sex, preterm gestation (<37 weeks), and young parental age (<20 years) were observed to be associated with an increased risk, whereas low birth weight (<2500 grams), higher maternal education (>high school), and non-white race/ethnicity were associated with a reduced risk among all cases combined and isolated cases. Subgroup analyses by sex for all PS cases yielded similar results, and also showed a higher prevalence of low birth weight and low gestational age among females compared to males.

Conclusions: This is the first large, multi-state, population-based study in the US on the prevalence of PS and associated infant and parental characteristics, including paternal race and ethnicity. Our findings offer an improved understanding of the prevalence of PS and descriptive characteristics of this defect in a large, well-described population, providing a continuum of information between 1999 and 2010, and serving as a sampling frame for future detailed investigations of infant and parental environmental and genetic risk factors for PS.

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