What are the risk factors for infantile hypertrophic pyloric stenosis (IHPS)?

From the Guidelines

Infantile hypertrophic pyloric stenosis is associated with several risk factors, including male sex, genetic predisposition, Caucasian ethnicity, young maternal age, smoking during pregnancy, and exposure to macrolide antibiotics in the first two weeks of life, as suggested by a study published in 2020 1. The condition typically presents between 2-8 weeks of age with projectile vomiting. Key risk factors include:

• Male sex, with boys being affected 4-6 times more frequently than girls
• Genetic component, with a 5-20 times increased risk in siblings of affected infants and higher concordance in monozygotic twins
• Caucasian ethnicity, associated with higher incidence compared to other racial groups
• Maternal factors, such as young maternal age, smoking during pregnancy, and bottle feeding rather than breastfeeding
• Certain medications, particularly macrolide antibiotics like erythromycin, especially when given to infants in the first two weeks of life, as noted in a study published in 2020 1
• Infants with certain blood types, such as B and O, may have slightly higher risk
• Seasonal variations, with higher rates in late summer and early fall in some studies
• Premature infants may have a slightly increased risk Understanding these risk factors can help clinicians maintain appropriate vigilance in high-risk infants, potentially leading to earlier diagnosis and treatment, as discussed in a study published in 2020 1.

From the Research

Risk Factors for Infantile Hypertrophic Pyloric Stenosis

• The etiology of infantile hypertrophic pyloric stenosis (IHPS) is largely unknown 2.
• Several factors have been associated with an increased risk of developing IHPS, including:
  • Genetic and environmental factors 3
  • Bottle feeding 3
  • Younger maternal age 3
  • Maternal smoking 3
  • Erythromycin administration in the first two weeks of life 3
  • Familial aggregation, with a family history seen in 47.9 percent of siblings 3

Demographic Risk Factors

• IHPS is the most common gastrointestinal disease among infants 3
• It occurs as an isolated condition or together with other congenital anomalies 3
• The condition is more common in males, with 86.4% of respondents in one study being male 4

Clinical Risk Factors

• Infants with IHPS typically present with projectile vomiting associated with symptoms of failure to thrive 3
• An olive-like mass palpable in the right upper abdominal quadrant is a common finding, although this is being reported less frequently due to earlier diagnosis by ultrasound 3