[1] Univ Witwatersr, Chris Hani Baragwanath Acad Hosp CHBAH, Natl Hlth Lab Serv NHLS, Div Anat Pathol, Johannesburg, South Africa
[2] Univ Malawi, Coll Med, Fac Hlth Sci, Zomba, Malawi
[3] Chris Hani Baragwanath Acad Hosp, Fac Hlth Sci, Dept Obstet & Gynaecol, Johannesburg, South Africa
[4] Univ Witwatersrand, Chris Hani Baragwanath Acad Hosp, Fac Hlth Sci, Johannesburg, South Africa