We used the WHO MultiCountry Survey on Maternal and Newborn Health (WHO
MCS) to create our reference population. Detailed description of this study has been published elsewhere.21 Briefly,
the WHO MCS was a cross-sectional study implemented in
359 health facilities in 29 countries. Countries, provinces (or
other equivalent political divisions within countries), and
health facilities were randomly selected to participate in the
WHO MCS through a stratified, multistage cluster sampling
strategy. Health facilities were only eligible if they dealt with