Umbilical artery pH values at birth and risk of asthma at 5 to 6 years of age.

BACKGROUND Intrapartum factors may have a role in the development of asthma and allergic diseases among offspring. OBJECTIVE To investigate the association between umbilical arterial pH values at birth and asthma, allergic rhinitis, and atopic eczema in children. METHODS We performed a case-control study of 222 asthmatic children and 183 control children aged 5 to 6 years with umbilical artery pH values recorded at birth. Associations were evaluated using logistic regression analysis. RESULTS Asthmatic children had significantly lower umbilical artery pH values at birth than nonasthmatics, even after adjusting. Children who were born with pH values of 7.20-7.25 had a 2.62-fold (95% confidence interval [CI], 1.31-5.23) higher risk of asthma and children who were born with umbilical arterial pH values < or = 7.19 had a 3.22-fold (95% CI, 1.51-6.87) higher risk of asthma than children who were born with umbilical arterial pH values of 7.26-7.30. In contrast, children who were born with umbilical arterial pH values > or = 7.30 had a 0.41-fold lower risk of atopic eczema than children who were born with umbilical arterial pH values of 7.26-7.30. No such association was detected between umbilical artery pH values and allergic rhinitis. CONCLUSIONS Stressful events at birth may play an important role in the development of asthma during early childhood. In contrast, higher umbilical arterial pH values were associated with a decreased risk of parent-reported atopic eczema at 5-6 years.