Smoking during pregnancy and infantile colic

Objective. To evaluate the association between maternal smoking during preg nancy and infantile colic (IC). Methods. A follow-up study of singleton infants delivered by Danish mothers at the Aarhus University Hospital from May 1991 to February 1992 and still living in the municipality of Aarhus at the age of 8 months was conducted. A total of 1820 mothers and their infants were included. Self-administered questionnaires were used to collect data on smoking, other lifestyle facto rs, and sociodemographic variables at 16 and 30 weeks of gestation and 8 mo nths postpartum. IC was defined in the 8-month questionnaire and based on W essel's criteria, except that we used only the crying criterion. Results. IC was seen in 10.8% of all infants. We observed a twofold increas ed risk of IC among infants whose mothers smoked 15 or more cigarettes per day during their pregnancy( relative risk: 2.1; 95% confidence interval: 1. 4-3.2) or in the postpartum period (relative risk: 2.0; 95% confidence inte rval: 1.3-3.1). Women who smoked continuously during pregnancy and the post partum period had a relative risk of 1.5 (95% confidence interval: 1.1-2.0) of having a infant with IC compared with women who did not smoke during th is period. Adjustment for maternal age, parity, marital status, alcohol int ake, birth weight, gestational age, breastfeeding, caffeine intake postpart um, and paternal smoking did not change the effect measures. Conclusion. The results indicate that maternal smoking during pregnancy may increase the risk of IC.