Delivering optimal weight gain advice to pregnant women by lead maternity carer midwives in a real-world setting to optimise health outcomes (DOT study): a case study protocol.

backgroundExcess gestational weight gain (GWG) occurs in up to 70% of women who birth. Excess GWG increases the risk of adverse outcomes in both mother and baby including gestational diabetes, pre-eclampsia, postpartum weight retention, large for gestational age babies, and adiposity among children. Antenatal lifestyle interventions can limit excess GWG. However, successful translation of interventions into routine antenatal care are seldom, and interventions involving midwives are uncommon. Following a successful feasibility study, the main aims of this study are to determine if the Delivering Optimal weighT gain advice in pregnancy (DOT) intervention is acceptable to midwives, acceptable and accessible to pregnant women, leads to improved pregnancy outcomes and reduces health inequities for Māori.

methodsThis is a mixed-methods case study in Te Tai Tokerau (Northland), Aotearoa New Zealand where 37.4% of the total, and half the birthing population are Māori. Independent Lead Maternity Carer midwives (15-20) will be trained to deliver the DOT intervention to 150-200 pregnant women aged ≥ 18 years. Women with pre-existing health conditions requiring specialist obstetric or dietetic care identified at the first antenatal visit will be excluded. The DOT intervention is goal-based and utilises the Starting the Conversation: Diet questionnaire. It is delivered over three visits, the first before 15 weeks gestation then 3-4 weekly. Routinely recorded clinical data including self-reported ethnicity, gravidity and parity, estimated date of delivery, anthropometry, blood pressure, antenatal blood tests, date and mode of delivery and infant birth weight will be collated. Costs associated with intervention delivery will be identified. The primary outcome measures are recruitment and retention. The secondary outcome measures are the cost of intervention delivery, rate of GWG, and birth weight. The acceptability of, and accessibility to, the intervention (enablers and barriers) will be explored qualitatively. Quantitative variables will be summarised using standard statistical methods. The rate of GWG will be described using linear mixed effect models. Qualitative data will be analysed thematically. DISCUSSION: A key goal of this research is to improve the repeatedly documented poor and inequitable health outcomes for Māori. A case study, unlike a RCT, will enable the context of the study to be considered.

trial registrationACTRN12623001228673 with the Australian New Zealand Clinical Trials Registry: 29 November 2023.