Maternal smoking and risk of hypertrophic infantile pyloric stenosis: 10 year population based cohort study

Abstract

We conducted the study between 1 January 1991 and 31 December 2000 in the Danish county of North Jutland and included data on all women who delivered a live infant after 28 weeks' gestation. The county birth registry contains information on all births since 1 January 1991. The main data comprise maternal age, self reported smoking status at the first visit to the midwife, birth order, gestational age, length and weight of neonates at birth, civil status, and civil registry numbers for both mother and child.