Blood pressure postpartum (BP2) RCT protocol: Follow-up and lifestyle behaviour change strategies in the first 12 months after hypertensive pregnancy

Objectives: Women who had hypertensive disorders of pregnancy (HDP) are twice as likely to experience maternal cardiovascular disease later in life. The primary aim of this study (BP2) is to compare outcomes of 3 different management strategies, including lifestyle behaviour change (LBC), in the first 12 months postpartum in women who had HDP in their preceding pregnancy. Secondary aims include assessing the effects on other cardiometabolic parameters. Study design: Three-arm multicentre randomised trial in metropolitan Australian hospitals, (registration: ACTRN12618002004246) target sample size 480. Participants are randomised to one of three groups: 1) Optimised usual care: information package and family doctor follow-up 6 months postpartum 2) Brief intervention: information package as per group 1, plus assessment and brief LBC counselling at a specialised clinic with an obstetric physician and dietitian 6 months postpartum 3) Extended intervention: as per group 2 plus enrolment into a 6 month telephone-based LBC program from 6 to 12 months postpartum. All women have an outcome assessment at 12 months. Main outcome measures: Primary outcomes: (a) BP change or (b) weight change and/or waist circumference change. Secondary outcomes: maternal health-related quality of life, engagement and retention in LBC program, biochemical markers, vascular function testing, infant weight trajectory, incremental cost-effectiveness ratios. The study is powered to detect a 4 mmHg difference in systolic BP between groups, or a 4 kg weight loss difference/2cm waist circumference change. Conclusions: BP2 will provide evidence regarding the feasibility and effectiveness of postpartum LBC interventions and structured clinical follow-up in improving cardiovascular health markers after HDP.