A Core Outcome Set for Studies of Intrahepatic Cholestasis of Pregnancy: Results of International e‐Delphi and Consensus Processes

OBJECTIVE: To define standardised outcomes, the Core Outcome Set (COS) for reporting in studies of Intrahepatic Cholestasis of Pregnancy (ICP). DESIGN: e-Delphi survey and consensus process. SETTING: International. POPULATION: 155 individuals from Asia, Europe, Oceania, North and South America: 31 patients (20%), 121 clinicians (78%), and 3 researchers (2%). METHODS: Maternal and perinatal outcomes reported in studies of ICP were collated. Stakeholders in ICP research and clinical care scored the importance of each outcome using a 9-point Likert scale over three rounds; short-listed outcomes were ranked during face-to-face consensus meetings. The final COS was agreed by the Study Steering Committee. The study was registered prospectively with Core Outcome Measures in Effectiveness Trials. Ethical approval was granted by the King's College London Research Ethics Committee (KCL MRA-23/24-39574). MAIN OUTCOME MEASURES: From 54 manuscripts, 97 individual clinical outcomes were attributed to ICP. Twenty three outcomes were shortlisted by the e-Delphi surveys, the ranking of which enabled selection of 10 core outcomes. RESULTS: Maternal core outcomes comprise: total maternal bile acid (BA) concentration (maximum), gestational age at peak BA concentration, and itch impact on maternal wellbeing. Birth core outcomes comprise: stillbirth, gestational age at birth, and spontaneous preterm birth versus induced preterm birth. Neonatal core outcomes comprise: perinatal death within 7 days of birth, perinatal asphyxia, neonatal unit admission, and mechanical ventilation. CONCLUSIONS: Given the heterogeneity of reported outcomes, we have confirmed the need for a COS in ICP, standardising the minimum reported outcomes to reduce outcome reporting bias and research wastage.