Funding for this research was provided by:
Received: 21 April 2020
Accepted: 25 December 2020
First Online: 22 January 2021
Change Date: 6 March 2021
Change Type: Correction
Change Details: A Correction to this paper has been published:
Change Details: https://0-doi-org.brum.beds.ac.uk/10.1186/S12978-021-01110-1
Ethics approval and consent to participate
: The trial protocol was approved by the relevant ethics committees and regulatory agencies in each country, by the Special Programme of Research in Human Reproduction (HRP) research proposals review panel based at the World Health Organization (WHO) and by the WHO Ethics Review Committee.
: Not applicable.
: We declare no competing interests.