[1] Acad Med Ctr, Dept Obstet & Gynaecol, POB 22770, NL-1100 DE Amsterdam, Netherlands
[2] Vrije Univ Amsterdam Med Ctr, Dept Obstet & Gynaecol, POB 7057, NL-1007 MB Amsterdam, Netherlands
[3] Univ Med Ctr Utrecht, Julius Ctr Hlth Sci & Primary Care, POB 85500, NL-3508 GA Utrecht, Netherlands
[4] Univ Amsterdam, Acad Med Ctr, Clin Res Unit, POB 22770, NL-1100 DE Amsterdam, Netherlands
[5] Groene Hart Hosp, Dept Obstet & Gynaecol, POB 1098, NL-2800 BB Gouda, Netherlands
[6] Onze Lieve Vrouwe Gasthuis West, Dept Obstet & Gynaecol, POB 9243, NL-1006 AE Amsterdam, Netherlands
[7] Univ Groningen, Univ Med Ctr Groningen, Dept Obstet & Gynaecol, POB 30001, NL-9700 RB Groningen, Netherlands
[8] Atrium Med Ctr, Dept Obstet & Gynaecol, POB 4446, NL-6401 CX Heerlen, Netherlands
[9] Maastricht Univ, Dept Obstet & Gynaecol, Med Ctr, POB 5800, NL-6202 AZ Maastricht, Netherlands
[10] Deventer Hosp, Dept Obstedtr & Gynaecol, POB 5001, NL-7400 GC Deventer, Netherlands
[11] Reinier de Graaf Hosp, Dept Obstet & Gynaecol, POB 5011, NL-2600 GA Delft, Netherlands
[12] Maxima Med Ctr, Dept Obstet & Gynaecol, Postbus 7777, NL-5500 MB Veldhoven, Netherlands
[13] St Franciscus Gasthuis, Dept Obstet & Gynaecol, POB 10900, NL-3004 BA Rotterdam, Netherlands
[14] Martini Hosp Groningen, Dept Obstet & Gynaecol, POB 30033, NL-9700 RM Groningen, Netherlands
[15] Radboud Univ Nijmegen Med Ctr, Dept Obstet & Gynaecol, POB 9101, NL-6500 HB Nijmegen, Netherlands
[16] Univ Adelaide, Robinson Res Inst, Sch Paediat & Reprod Hlth, 55 King William Rd, Adelaide, SA 5006, Australia
[17] South Australian Hlth & Med Res Inst, Adelaide, SA, Australia