title: Ongoing normal pregnancy after transfer of zona-free blastocysts: implications for embryo transfer in the human.
abstract: Recent reports suggest that transfer of day 5 blastocysts improves implantation rates in in-vitro fertilization programmes. This paper reports a successful ongoing pregnancy after the transfer of zona-free day 6 expanded and hatching blastocysts. The patient was 37 years old and had undergone six stimulated and two thaw cycles previously, all of which had failed. Stimulation was by down-regulation and oocytes recovered transvaginally by ultrasound guidance. Two pronuclear embryos were co-cultured on Vero cells to day 6. The zonae of two hatching and two fully expanded blastocysts were removed using 0.5% pronase, and the zona-free blastocysts were then transferred. Pregnancy was confirmed on day 18 with a positive human chorionic gonadotrophin (HCG) and ultrasound at 6 weeks showed a single healthy fetal heart inside a clear sac. At 14 weeks a triple test (oestriol, J-HCG and alpha-fetoprotein) was normal and at 22 weeks a detailed ultrasound scan showed no congenital anomalies. This is the first report in the human of a normal ongoing pregnancy after the transfer of zona-free day 6 embryos.
authors.affiliation: Department of Obstetrics and Gynaecology, National University Hospital, Singapore.
authors.forename: C Y
authors.initials: CY
authors.lastname: Fong
authors.forename: A
authors.initials: A
authors.lastname: Bongso
authors.forename: S C
authors.initials: SC
authors.lastname: Ng
authors.forename: C
authors.initials: C
authors.lastname: Anandakumar
authors.forename: A
authors.initials: A
authors.lastname: Trounson
authors.forename: S
authors.initials: S
authors.lastname: Ratnam
mesh_terms: D000328:Adult; D001755:Blastocyst; D004624:Embryo Transfer / Q000379:methods*; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods*; D006801:Humans; D008297:Male; D011247:Pregnancy; D016216:Ultrasonography, Prenatal; D015044:Zona Pellucida / Q000502:physiology*