UHPLC-MS/MS progestin quantification methods.
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(DOCX)Click here for additional data file.We thank all the participants who participated in the WHICH clinical trial. We thank Karen van der Merwe for project administration and assistance in preparation and submission of the manuscript. We thank Marietjie Stander and Erick van Schalkwyk for assistance with the UHPLC-MS/MS assays.