British Journal of Health Psychology (2016), 21, 31–51 © 2015 The British Psychological Society www.wileyonlinelibrary.com Health coaching to prevent excessive gestational weight gain: A randomized-controlled trial Helen Skouteris 1 *, Skye McPhie 1 , Briony Hill 1 , Marita McCabe 1 , Jeannette Milgrom 2 , Bridie Kent 3 , Lauren Bruce 1 , Sharon Herring 4 , Janette Gale 5 , Cathrine Mihalopoulos 6 , Sophy Shih 6 , Glyn Teale 7 and Jennifer Lachal 8 1 School of Psychology, Deakin University, Burwood, Victoria, Australia 2 School of Psychological Sciences, University of Melbourne, Parkville, Victoria, Australia 3 School of Nursing and Midwifery, Drake Circus, Plymouth University, Devon, UK 4 Section of General Internal Medicine, Department of Medicine, Temple University, Philadelphia, Pennsylvania, USA 5 Healthchange Australia, Bomaderry, New South Wales, Australia 6 Deakin Health Economics, Deakin University, Burwood, Victoria, Australia 7 Women’s and Children’s Services, Western Health, Sunshine Hospital, St Albans, Victoria, Australia 8 Carrington Health, Box Hill, Victoria, Australia Objectives. The objectives of this study were to evaluate the efficacy of a health coaching (HC) intervention designed to prevent excessive gestational weight gain (GWG), and promote positive psychosocial and motivational outcomes in comparison with an Education Alone (EA) group. Design. Randomized-controlled trial. Methods. Two hundred and sixty-one women who were <18 weeks pregnant consented to take part. Those allocated to the HC group received a tailored HC intervention delivered by a Health Coach, whilst those in the EA group attended two education sessions. Women completed m\easures, including motivation, psychosocial variables, sleep quality, and knowledge, beliefs and expectations concerning GWG, at 15 weeks of gestation (Time 1) and 33 weeks of gestation (Time 2). Post-birth data were also collected at 2 months post-partum (Time 3). Results. There was no intervention effect in relation to weight gained during pregnancy, rate of excessive GWG or birth outcomes. The only differences between HC and EA women were higher readiness (b = 0.29, 95% CIs = 0.03–0.55, p < .05) and the importance to achieve a healthy GWG (b = 0.27, 95% CIs = 0.02–0.52, p < .05), improved sleep quality (b = 0.22, 95% CIs = 0.44 to 0.03, p < .05), and increased knowledge for an appropriate amount of GWG that would be best for their baby’s health (b = 1.75, 95% CI = 3.26 to 0.24, p < .05) reported by the HC at Time 2. *Correspondence should be addressed to Helen Skouteris, School of Psychology, Deakin University, 221 Burwood Highway, Burwood, Vic. 3125, Australia (email: helen.skouteris@deakin.edu.au). DOI:10.1111/bjhp.12154 31