ObjectiveThe ACROBAT pilot trial of early cryoprecipitate for severe postpartum haemorrhage used deferred consent procedures. Pretrial discussions with a patient and public involvement group found mixed views towards deferred consent. This study aimed to build an understanding of how the deferred consent procedures worked in practice, to inform plans for a full-scale trial.SettingQualitative interview study within a cluster-randomised pilot trial, involving four London maternity services.ParticipantsIndividual interviews were conducted postnatally with 10 women who had received blood transfusion for severe postpartum haemorrhage and had consented to the trial. We also interviewed four ‘recruiters’—two research midwives and two clinical trials practitioners who conducted trial recruitment.ResultsConsent procedures in the ACROBAT pilot trial were generally acceptable and the intervention was viewed as low risk, but most women did not remember much about the consent conversation. As per trial protocol, recruiters sought to consent women before hospital discharge, but this time pressure had to be balanced against the need to ensure women were not approached when distressed or very unwell. Extra efforts had to be made to communicate trial information to women due to the exhaustion of their recovery and competing demands for their attention. Participant information was further complicated by explanations about the cluster design and change in transfusion process, even though the consent sought was for access to medical data.ConclusionOur findings indicate that deferred consent procedures raise similar concerns as taking consent when emergency obstetric research is occurring—that is, the risk that participants may conflate research with clinical care, and that their ability to process trial information may be impacted by the stressful nature of recovery and newborn care. A future trial may support more meaningful informed consent by extending the window of consent discussion and ensuring trial information is minimal and easy to understand.Trial registration numberISRCTN12146519.