[1] Katutura State Hosp, Dept Obstet & Gynaecol, Windhoek, Namibia
[2] Univ Med Ctr Groningen, Dept Hlth Sci, Global Hlth Unit, Groningen, Netherlands
[3] Med Ctr Leeuwarden, Dept Obstet & Gynaecol, Leeuwarden, Netherlands
[4] Leiden Univ, Dept Obstet & Gynaecol, Med Ctr, Leiden, Netherlands
[5] Vrije Univ Amsterdam, Fac Sci, Athena Inst, Amsterdam, Netherlands
[6] Univ Med Ctr Hamburg Eppendorf, Dept Med, Hamburg, Germany
[7] Borders Gen Hosp, Dept Obstet & Gynaecol, Melrose, Scotland