[1] Univ Stellenbosch, MediClin Panorama, Cape Town, South Africa
[2] Univ Stellenbosch, Dept Obstet & Gynecol, Cape Town, South Africa
[3] Case Western Reserve Univ, Sch Med, Dept Surg, Cleveland Clin,Lerner Coll Med, Cleveland, OH 44106 USA
[4] Chinese Univ Hong Kong, Dept Obstet & Gynecol, Prince Wales Hosp, Shatin, Hong Kong, Peoples R China
[5] Massachusetts Gen Hosp, Dept Med, Boston, MA 02114 USA
[6] Harvard Univ, Sch Med, Boston, MA USA
[7] Columbia Univ, Dept Obstet & Gynecol, New York, NY USA
[8] Univ Geneva, CH-1211 Geneva 4, Switzerland
[9] Univ Oxford, Oxford OX1 2JD, England