What influences women’s decisions to participate in trials for prevention of venous thromboembolism during pregnancy and the puerperium: a qualitative study

BACKGROUND: Thromboprophlyaxis for the prevention of venous thromboembolism during pregnancy and the puerperium is widespread, but there is a lack of evidence on the risks and benefits of thromboprophylaxis within this population. Trials involving pregnant women often struggle to recruit and retain participants which makes It difficult to improve the evidence base. We undertook qualitative evaluation of patient perspectives of pregnancy/postpartum thromboprophylaxis to understand willingness to participate in future trials. METHODS: We undertook four focus groups of women who had thromboprophylaxis due to prior VTE (n = 10) or been offered thromboprophylaxis due to other risk factors (n = 12) during pregnancy and the puerperium. Focus groups were held online between November 2021 and January 2022. We recruited via social media and national special interest groups representing diverse cultural and socio-economic backgrounds, sampling purposively for condition, age, ethnicity, and socio-economic status. Participants received a £50 voucher. We transcribed focus groups and analysed data using thematic analysis. RESULTS: A lack of knowledge around the risks and benefits of thromboprophylaxis influenced how women perceived future trial participation. Limited understanding of thromboprophylaxis risks led to a lack of equipoise among participants who only identified benefits from treatment. Some women were unaware of why they had been given thromboprophylaxis but still perceived placebo as an inferior option. Concerns around injecting thromboprophylaxis were often minimised and ignored by healthcare professionals yet influenced treatment adherence. However, these negative experiences also motivated women to participate in future trials to receive a higher standard of care, as well as improving future care for others. CONCLUSIONS: Trial treatment adherence may be affected by negative experiences of injecting and limited understanding of why they had been offered thromboprophylaxis. To improve recruitment and retention in pregnancy and puerperium clinical trials, women need to be given clear explanations of the risks and benefits of treatment and understand where there is genuine clinical equipoise. Improved communication may also improve the experience and treatment adherence for women currently being offered thromboprophylaxis.