Pragmatic cluster randomised trial of a free telephone-based health coaching program to support women in managing weight gain during pregnancy: the Get Healthy in Pregnancy Trial

Background: Excessive gestational weight gain can result in poor maternal and child health outcomes. Estimates from single studies indicate the prevalence of excessive gestational weight gain in Australia could lie between 38 and 67 %. The risk of excessive weight gain can be reduced through healthy eating and exercise. We describe the rationale and methods of the Get Healthy in Pregnancy Service, a trial service which aims to support women in achieving appropriate gestational weight gain through an existing telephone-based health coaching service.Methods/Design: This study aims to compare the effectiveness of a telephone-based health coaching program versus provision of information only in supporting pregnant women to achieve appropriate gestational weight gain. A pragmatic stratified clustered randomised controlled trial will be conducted with 710 women who present to 5 hospitals for their first antenatal appointment during the recruitment period (6-8 months), have a pre-pregnancy body mass index (BMI) >= 18.50 (healthy weight or above), are 18 years and over, singleton gestation, English speaking, have no pre-existing medical conditions that may limit their ability to exercise or require a restricted diet and are 18 weeks or less gestation. Hospitals will be randomised into one of two intervention models: a) information only; or b) information plus 10 telephone-based health coaching sessions with a university qualified coach. Both interventions will set a weight-range target with pregnant women. The women attending antenatal clinics at participating hospitals will be screened at their initial hospital appointment to assess their eligibility. Women recruited to the trial will have a number of measures recorded including anthropometrics (self-reported height and weight) and dietary and physical activity scores during and following pregnancy. These measurements will be collected at baseline (prior to 18 weeks gestation), 36 weeks gestation and 12 months post-birth.Discussion: This study responds to a need for an effective intervention that targets excessive gestational weight gain at a population level. This study investigates the potential for an innovative intervention combining two existing services; a free state-wide telephone-based health coaching service and hospital-based antenatal care to support pregnant women to achieve healthy weight gain during pregnancy. The use of existing services provides the potential for immediate post-study implementation. While the impacts of telephone-based lifestyle programmes have been tested in a number of settings, there are few studies which evaluate the effectiveness and acceptability of telephone support in achieving healthy gestational weight gain in association with routine antenatal care.