ACORN: A multi-site randomised COntrolled trial to evaluate the impact of a group tReatment for aNtenatal anxiety

Background: 27% of women will experience mental health difficulties during pregnancy (1), of which 99% are common mental health problems (1); anxiety is the most prevalent with 15-22% of women struggling with significant anxiety (2). This is a serious concern because anxiety is disabling, symptoms do not improve without treatment, often persist postnatally and for some, lead to depression. High anxiety during pregnancy is also related to risk for negative childbirth outcomes and child development including poorer social, emotional and cognitive development (3). Maternal anxiety that persists after birth can lead to impaired bonding and parenting difficulties (4). The impact of untreated perinatal mental health problems costs England over £8 billion for each birth cohort (5). Despite the extent and severity of antenatal anxiety, there is a striking lack of high-quality intervention research about the best help for mothers. In the NHS, most mothers with antenatal anxiety (65%) can receive treatment in primary mental health care (Improving Access to Psychological Therapies, IAPT), but IAPT lacks treatments that specifically address antenatal anxiety and few pregnant women currently engage with IAPT (<30%; 6,7). To address this gap, we co-developed and tested a 5-session group intervention (CALM) that gives pregnant women tools to manage their antenatal anxiety, based on extensive consultation about their needs. The intervention is co-delivered by a healthcare and psychological worker, includes partners/close supporter and encourages peer support amongst members. Aims and Objectives: Our feasibility study established that women and their partners can be readily recruited to the CALM intervention and view treatment positively. CALM reduced mothers’ anxiety. We now propose a fully powered trial to evaluate whether CALM plus usual treatment is more effective in reducing antenatal anxiety compared to usual treatment on its own. We will test whether CALM 1) improves anxiety in pregnant women; 2) has sustained benefits up to a year after the baby is born; 3) improves the parent-infant relationship and child development and 4) is cost-effective for the NHS to deliver. We will also interview participating parents and care providers to identify components of the CALM intervention that are perceived to be most beneficial and the best ways to ensure CALM fits within the NHS. Methods: Over an 18-month-period, we will recruit 484 women to the trial from five urban and rural sites with varied ethnic and income compositions. We will work with community connectors to engage pregnant women from diverse backgrounds. We will deliver CALM remotely/online because our experts-by-experience recommended this approach to improve parents’ participation. Many perinatal psychological treatments are already being delivered online across the NHS and in clinical trials. We will have a tablet loan library (and data) allowance for those who need this. Impact: Our team has extensive experience developing, testing, and implementing perinatal mental health treatments into NHS services. We have expertise in trial design, service user involvement, health economics, child development, statistics, and process evaluation. If funded, this will be the first large trial to test the effectiveness and long-term benefits of a group treatment for antenatal anxiety. It has the potential to make a real difference to women and families and could be delivered widely across the NHS.