The incidence of infantile hypertrophic pyloric stenosis and its association with folic acid supplementation during pregnancy: A nested case–control study

Nested case-control study examining 1,899 IHPS cases in Israel (1999-2015) found declining incidence from 4.3 to 2.1 per 1,000 live births, potentially associated with increased maternal folic acid supplementation during pregnancy. Study matched cases with 7,350 controls to assess relationship between prenatal folic acid consumption and IHPS risk.