title: Implantation of fresh and thawed-warmed embryos in single embryo transfer cycles: interpreting the initial beta-HCG.
abstract: Little is known about the effects of human embryo cryopreservation on developmental potential. Initial beta-HCG, indicating embryo implantation, was measured in 322 single embryo transfer cycles (246 fresh and 76 thawed-warmed). Median initial beta-HCG was higher for fresh compared with thawed-warmed transfers (126 versus 100 mIU/ml; P = 0.04). Blastocyst slow cooling resulted in a lower initial beta-HCG compared with vitrification (P = 0.01). Live birth rates were lower for blastocyst slow cooling (25%) compared with vitrification (71%) and fresh transfer (70%). We conclude that cryopreservation may impair an embryo's ability to produce beta-HCG, but that vitrification does not impair developmental potential.
authors.affiliation: Baystate Medical Center, Department of Obstetrics and Gynecology, Tufts University School of Medicine, 759 Chestnut Street, S1683, Springfield, MA, 01199, USA. Electronic address: Cynthia.Sites@baystatehealth.org.
authors.forename: Cynthia K
authors.initials: CK
authors.lastname: Sites
authors.affiliation: Baystate Medical Center, Department of Obstetrics and Gynecology, Tufts University School of Medicine, 759 Chestnut Street, S1683, Springfield, MA, 01199, USA.
authors.forename: Peter
authors.initials: P
authors.lastname: St Marie
authors.affiliation: Baystate Medical Center, Department of Obstetrics and Gynecology, Tufts University School of Medicine, 759 Chestnut Street, S1683, Springfield, MA, 01199, USA.
authors.forename: Tayyab
authors.initials: T
authors.lastname: Rahil
mesh_terms: D000328:Adult; D001723:Birth Rate; D001755:Blastocyst; D018997:Chorionic Gonadotropin, beta Subunit, Human / Q000097:blood*; D002970:Cleavage Stage, Ovum; D015925:Cryopreservation / Q000379:methods*; D004477:Ectogenesis; D046149:Embryo Culture Techniques; D020964:Embryo Loss / Q000209:etiology / Q000517:prevention & control; D047108:Embryonic Development; D005260:Female; D005307:Fertilization in Vitro / Q000009:adverse effects; D006801:Humans; D007118:Immunoassay; D008404:Massachusetts / Q000453:epidemiology; D011247:Pregnancy; D018873:Pregnancy Rate; D012189:Retrospective Studies; D056826:Single Embryo Transfer / Q000009:adverse effects; D058989:Vitrification
chemical_list: D018997:Chorionic Gonadotropin, beta Subunit, Human
keywords: blastocyst; cryopreservation; embryos; single embryo transfer; vitrification; βhCG