An implementation intervention to increase the routine provision of antenatal care addressing gestational weight gain: study protocol for a stepped-wedge cluster trial

Abstract
Background
Weight gain during pregnancy that is outside of recommended levels is associated with a range of adverse outcomes for the mother and child, including gestational diabetes, pre-eclampsia, preterm birth, and obesity. Internationally, 60–80% of pregnant women report gaining weight outside of recommended levels. While guideline recommendations and RCT evidence support the provision of antenatal care that supports healthy gestational weight gain, less than 10% of health professionals routinely weigh pregnant women; discuss weight gain, diet, and physical activity; and provide a referral for additional support. This study aims to determine the effectiveness of an implementation intervention in increasing the provision of recommended gestational weight gain care by maternity services.

Methods
A stepped-wedge controlled trial, with a staggered implementation intervention, will be conducted across maternity services in three health sectors in New South Wales, Australia. The implementation intervention will consist of evidence-based, locally-tailored strategies including guidelines and procedures, reminders and prompts, leadership support, champions, training, and monitoring and feedback. Primary outcome measures will be the proportion of women who report receiving (i) assessment of gestational weight gain; (ii) advice on gestational weight gain, dietary intake, and physical activity; and (iii) offer of referral to a telephone coaching service or local dietetics service. Measurement of outcomes will occur via telephone interviews with a random sample of women who attend antenatal appointments each week. Economic analyses will be undertaken to assess the cost, cost-consequence, cost-effectiveness, and budget impact of the implementation intervention. Receipt of all care elements, acceptance of referral, weight gain during pregnancy, diet quality, and physical activity will be measured as secondary outcomes. Process measures including acceptability, adoption, fidelity, and reach will be reported.

Discussion
This will be the first controlled trial to evaluate the effectiveness of a implementation intervention in improving antenatal care that addresses gestational weight gain. The findings will inform decision-making by maternity services and policy agencies and, if the intervention is demonstrated to be effective, could be applied at scale to benefit the health of women and children across Australia and internationally.

Trial registration
Australian and New Zealand Clinical Trials Registry, ACTRN12621000054819. Registered on 22 January 2021