ObjectivesThe incidence of gallstone disease has increased recently in Korea and there seems to be an increased prevalence of gallstones when in association with pregnancy. Although the pathogenesis is incompletely defined, an altered motility of the gallbladder may contribute to the increased risk of gallstones during pregnancy.MethodsWe measured gallbladder volume using real-time ultrasonography to find out the mechanism for the changes of gallbladder motility during late pregnancy. Eighteen pregnant women took the gallbladder ultrasonography during their last trimester of pregnancy and after delivery: gallbladder volume and ejection fraction were calculated in each patient.ResultsFasting gallbladder volumes increased significantly in the last trimester of pregnancy (25.28± 14.26ml) compared with postpartum (17.44±5.82ml) (p<0.05). Gallbladder volumes measured after fatty meals showed more increment in pregnant women (10.13±7.19ml) than in those after delivery (4.34±3.36ml) (p<0.005). A significantly reduced gallbladder ejection fraction was found in the pregnant group (60.56± 18.80%) compared with those after delivery (77.48± 13.37%) (p<0.005).ConclusionGallbladder motility in late pregnancy shows significant impairment compared with that in postpartum. Thus, we suggest that gallbladder hypomotility may occur during late pregnancy, and this impairment of gallbladder motility may play an important role in gallstone formation.