[1] Oregon Hlth & Sci Univ, Dept Obstet & Gynecol, Portland, OR 97201 USA
[2] Univ Stellenbosch, Tygerberg Hosp, Dept Obstet & Gynaecol, Fac Med & Hlth Sci, Francie van Zyl Dr, ZA-7505 Cape Town, South Africa
[3] Oregon Hlth & Sci Univ, Fertil Regulat Grp, Portland, OR USA
[4] Fudan Univ, NHC Key Lab Reprod Regulat, Shanghai Inst Biomed & Pharmaceut Technol, Shanghai, Peoples R China
[5] Amer Soc Emergency Contracept, Princeton, NJ USA
[6] Beth Israel Deaconess Med Ctr, Boston, MA 02215 USA