Study selection
We included randomised control trials focussed on management of HDP where one treatment arm comprised of CCBs, and the study demographics explicitly stated involvement of Black pregnant women. Studies were included in our review if they met the following criteria: (1) study involved treatment of HDP; (2) study was of a randomised control trial design; (3) one of the treatment arms involved CCBs and (4) English full-text. Studies were excluded if relevant outcome data were not reported or there was no mention of ethnicity or race demographics within the study. We also excluded case-control studies, case reports, reviews, letters to editors, and animal/in vitro studies. Corresponding authors were contacted individually to obtain the full text article or where additional information was required if inclusion criteria were met based on the information provided in the abstract. All study abstracts were independently screened by two authors (J.J. and G.C.) with disagreements reviewed and settled by discussion. Following abstract screening, potentially eligible studies underwent full-text review by the same authors.