title: The influence of number of embryos transferred on pregnancy outcome in women undergoing in vitro fertilization and embryo transfer (IVF-ET).
abstract: The purpose of this study was to retrospectively examine the influence of number of embryos transferred on pregnancy outcome in women undergoing in vitro fertilization and embryo transfer (IVF-ET) between July 1990-December 1991 at the Royal Free Hospital, London, United Kingdom. This study included three groups of patients: group 1-the number of embryo used for transferring was one embryo, group 2-the number of embryos used for transferring was two embryos and group 3-the number of embryos used for transferring was three embryos. This study demonstrated that the clinical pregnancy rate increased significantly when transferring two or three embryos compared to one. But this rate did not differ significantly when two embryos were compared with three embryos. The multiple pregnancy rate, miscarriage rate, and ectopic pregnancy rate did not differ significantly among the three groups studied but there was a risk of higher order multiple pregnancy if more embryos were transferred. In this study we found 3 triplets out of 35 pregnancies when 3 embryos were transferred (Group 3). In conclusion, this study demonstrates that when two or three embryos were transferred the clinical pregnancy rate increased significantly. Transferring two embryos instead of three did not alter the pregnancy rate. Moreover, triplets pregnancies were eliminated. Therefore, we suggest limiting the number of embryos to be transferred at two and the supernumerary embryos should be cryopreserved for future transfer.
authors.affiliation: Department of Obstetrics and Gynaecology, Faculty of Medicine, Ramathibodi Hospital, Bangkok, Thailand.
authors.forename: S
authors.initials: S
authors.lastname: Preutthipan
authors.forename: N
authors.initials: N
authors.lastname: Amso
authors.forename: P
authors.initials: P
authors.lastname: Curtis
authors.forename: R W
authors.initials: RW
authors.lastname: Shaw
mesh_terms: D000328:Adult; D004624:Embryo Transfer / Q000379:methods*; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods*; D006801:Humans; D007226:Infant Mortality; D007231:Infant, Newborn; D007247:Infertility, Female / Q000628:therapy*; D009017:Morbidity; D011247:Pregnancy; D011256:Pregnancy Outcome; D011272:Pregnancy, Multiple; D012189:Retrospective Studies; D012307:Risk Factors