[1] Vanderbilt Univ, Vanderbilt Inst Global Hlth, Med Ctr, Nashville, TN 37232 USA
[2] Kaduna State Univ, Barau Dikko Teaching Hosp, Dept Hematol & Blood Transfus, Kaduna, Nigeria
[3] Univ Ghana, Dept Obstet & Gynecol, Med Sch, Accra, Ghana
[4] Korle Bu Teaching Hosp, Dept Obstet & Gynecol, Accra, Ghana
[5] Univ Oslo, Inst Hlth, Fac Med, Dept Community Med & Global Hlth, Oslo, Norway