[영문]Background.Pregnant women suffer from sleep disturbance, which may be aggravated by smoking and/or drinking. We investigate here the joint effect of smoking and drinking with respect to sleep disturbance during pregnancy.Methods.Survey of about 16,000 pregnant women in Japan, conducted in 2002 using a self-administered questionnaire.Results.Both smoking and drinking increased the odds of sleep disturbances, such as subjective insufficient sleep, difficulty in initiating or maintaining sleep, early-morning awakening, short sleep duration, excessive daytime sleepiness and restless legs syndrome. The joint odds ratios for smoking and drinking corresponded more or less to the products of the odds ratio for smoking or drinking.Conclusion.Smoking and drinking are independently associated with increased sleep disturbance during pregnancy, in addition to their other well-known side-effects.