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 ≤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 ≥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.

Key words: Asthma. Birth. Allergic rhinitis. Atopic eczema. pH. Umbilical cord.