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BACKGROUND Peri-operative fasting guidelines allow clear fluids including tea without milk to be consumed up to 2 h before surgery. Recent evidence has shown that a modest amount of milk consumed with clear fluids does not significantly slow gastric emptying. OBJECTIVES The aim of this study was to compare the gastric emptying of tea with milk versus water using ultrasonography in fasted pregnant patients. DESIGN A randomised controlled trial quantifying gastric emptying in two groups using ultrasonography by an operator blinded to the group allocation. SETTING Department of Anaesthesia and Peri-operative Medicine, Coombe Women and Infants University Hospital, Dublin. The study was conducted between October 2018 and June 2019. PARTICIPANTS Total 50 nonlabouring pregnant women, more than 36 weeks gestation. INTERVENTIONS After a standard overnight fast, women were randomised to either 250 ml of water or 250 ml of tea with milk. All patients underwent a gastric ultrasound assessment at regular intervals for 2 h after consumption of their drink. MAIN OUTCOME MEASURE The primary outcome was the difference in gastric antrum cross-sectional area (CSA) at 2 h. RESULTS A total of 50 women were recruited to the study. There was no significant difference in the median [IQR] gastric antrum CSA in either group at 2 h: 3.2 cm [2.3 to 3.7] vs. 3.1 cm [2.6 to 3.9]; P = 0.720. The gastric antrum CSA had returned to its baseline measurement in both groups by 90 min. CONCLUSION The change of gastric antrum CSA after 250 ml of tea with milk is similar to a corresponding volume of water in fasted pregnant patients. This study could help inform future peri-operative fasting guidelines regarding the use of a modest volume of milk with clear fluids. TRIAL REGISTRY NUMBER NCT03694509 ClinicalTrials.gov.