title: Day 5 versus day 3 embryo transfer: a controlled randomized trial.
abstract: Blastocyst transfer has been suggested to improve implantation rate without affecting pregnancy rate. The aim of this study was to compare the pregnancy and implantation rates of day 3 and 5 transfers in a prospective randomized manner. Patients with four or more zygotes were randomly allocated on day 1 to either day 3 or 5 transfers. Fertilization was achieved through regular IVF or intracytoplasmic sperm injection. Zygotes were kept in Medicult IVF medium for day 3 transfers and transferred into G1.2 and G2.2 on day 1 and 3 respectively for day 5 transfers. The morphologically best two or three embryos or blastocysts were chosen for transfer in both groups. Overall pregnancy rates per embryo transfer were the same (39%) in day 3 and 5 transfers. Implantation rates were 21 and 24% for day 3 and 5 transfers respectively. The pregnancy and implantation rates for day 5 transfers were significantly affected by the availability of at least one blastocyst to transfer and the number of zygotes. The number of good quality embryos on day 3 also significantly affected pregnancy and implantation rates on day 5 transfers. Multiple gestation rate, number of abortions and ongoing pregnancies were similar in both groups. In conclusion, day 3 and 5 transfer had similar pregnancy, implantation and twinning rates. Currently, day 5 transfers have no advantages over day 3 transfers.
authors.affiliation: Departments of Pathology and Laboratory Medicine and Obstetrics and Gynecology, King Faisal Specialist Hospital and Research Center, P.O. Box 3354, Riyadh, Saudi Arabia.
authors.forename: S
authors.initials: S
authors.lastname: Coskun
authors.forename: J
authors.initials: J
authors.lastname: Hollanders
authors.forename: S
authors.initials: S
authors.lastname: Al-Hassan
authors.forename: H
authors.initials: H
authors.lastname: Al-Sufyan
authors.forename: H
authors.initials: H
authors.lastname: Al-Mayman
authors.forename: K
authors.initials: K
authors.lastname: Jaroudi
mesh_terms: D000328:Adult; D001755:Blastocyst / Q000502:physiology*; D046508:Culture Techniques; D010064:Embryo Implantation; D004624:Embryo Transfer / Q000379:methods*; D004622:Embryo, Mammalian / Q000502:physiology; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D011247:Pregnancy; D011446:Prospective Studies; D020554:Sperm Injections, Intracytoplasmic; D013997:Time Factors