Contributions to authorship
SMC developed the concept for the study and initiated the protocol.
CE advised on the biochemistry components of the protocol and led the identification of potential recruits.
AS advised on practical points in the protocol and led the recruitment of subjects.
EJC led the department in which CEB conducted the HE4 assays and both contributed to the interpretation of findings.
All authors agreed the text of the manuscript.
The study was approved by Cambridge East Research Ethics Committee 225328, 28 December 2018.