Abstract Study question How does the Positive Reappraisal Coping Intervention (PRCI) sustain coping during the early stages of a new pregnancy in women with recurrent pregnancy loss (RPL)? Summary answer The PRCI improved psychological well being by sustaining coping and providing psychological respite from the stress of uncertainty. What is known already Increased levels of maternal anxiety and uncertainty are common during the early stages of a new pregnancy following RPL when women wait for confirmatory scan of ongoing pregnancy, however psychological support is often limited. The PRCI is a self-administered coping tool developed for uncontrollable and unpredictable situations like waiting, theorised to achieve its benefits by promoting positive feelings alongside negative feelings in unrelenting stressor situations, sustaining coping. It has been shown to have benefits for those awaiting the outcome of fertility treatment and those experiencing RPL by increasing positive emotions, positive appraisals of the situation and emotional quality of life. Study design, size, duration We performed secondary analysis of qualitative data from a two-centred feasibility randomised controlled study on the effectiveness of the PRCI for psychological well being of women with RPL. Participants (n = 75) were recruited over a two-year period. Participants for the qualitative component of the study (n = 14), participated in semi-structured interviews exploring their experience of pregnancy following RPL, perception of study methods and the intervention. Participants/materials, setting, methods Participants were recruited from the Recurrent Miscarriage Clinic in two tertiary referral hospitals in the UK. Women who had experienced three or more pregnancy losses were eligible to participate. Semi-structured interviews were conducted face to face. Data for the secondary analysis were interview data from the intervention arm of the study, that received the PRCI. Interview transcripts were analysed using NVivo 12 software and the approach of Braun and Clarke (2006). Main results and the role of chance This secondary analysis focused on improving understanding of the mechanisms by which the PRCI was perceived to be effective at promoting maternal psychological well being during the challenging early stages of a new pregnancy following RPL. Inductive thematic analysis of the qualitative data identified three themes on which the main theme of ‘PRCI sustains coping’ was based, namely that PRCI: •· prevented further falling or spiralling down by stimulating questioning of negative thoughts and encouraging time out for oneself •· encouraged an ‘I can do this’ attitude, acting as a reminder of the positives and stimulating positive thinking in this experience •· was perceived a helpful coping resource to lean on The study identified that the PRCI was a ‘go to’ resource in taxing moments of need, conveying benefits to maternal psychological well being by restoring depleted coping resources, stimulating positive coping, and providing psychological respite from the stressor of uncertainty experienced during the early stages of a new pregnancy. There were no apparent downsides of use. These insights are consistent with theory of how positive reappraisal helps people carry on coping in challenging situations. Limitations, reasons for caution Since this is a secondary analysis, data was utilised from a study that was not originally designed to investigate the perceived mechanism of the PRCI, and as such the data should be interpreted cautiously. Wider implications of the findings PRCI has the potential to be made more widely available as an effective, safe, convenient, and low-cost intervention to provide emotional support in RPL clinics. It might also be a useful coping technique in other clinical contexts where patients/carers experience increased psychological strain because of prolonged periods of uncertainty. Trial registration number ISCTN43571276