[1] Natl Univ Singapore, Yong Loo Lin Sch Med, Expt Fetal Med Grp, Dept Obstet & Gynecol, Singapore 117595, Singapore
[2] Natl Univ Singapore, Singapore 117548, Singapore
[3] KK Womens & Childrens Hosp, Dept Reprod Med, Singapore 228899, Singapore
[4] Duke Natl Univ Singapore Grad Med Sch, Canc & Stem Cell Biol, Singapore, Singapore
[5] Karolinska Inst, Dept Clin Sci Intervent & Technol, Div Obstet & Gynecol, Stockholm, Sweden
[6] Karolinska Inst, Ctr Hematol & Regenerat Med, Stockholm, Sweden