title: Where does the embryo implant after embryo transfer in humans?
abstract: OBJECTIVE
  To investigate where human embryos implant after ET.
  
  
  METHODS
  Prospective analysis.
  
  
  METHODS
  University hospital.
  
  
  METHODS
  Sixty infertile women without uterine fibroids, a major uterine anomaly, or a history of cesarean section.
  
  
  METHODS
  Transabdominal and transvaginal three-dimensional ultrasound examinations.
  
  
  METHODS
  The location of ET-associated air bubbles in the uterine cavity and the location of the resultant gestational sac.
  
  
  RESULTS
  Sixty ETs resulted in 22 pregnancies, and 32 gestational sacs were located. Twenty-six of the 32 embryos were within or between the area in which the catheter tip was situated and the area over which air bubbles had spread immediately after ET.
  
  
  CONCLUSIONS
  In cases of pregnancy achieved through ET, approximately 80% of embryos implant in areas to which they initially are transferred and approximately 20% implant in other areas.
authors.affiliation: Department of Obstetrics and Gynecology, Saitama Medical Center, Saitama Medical School, Kawagoe, Japan. baba@bme.rcast.u-tokyo.ac.jp
authors.forename: K
authors.initials: K
authors.lastname: Baba
authors.forename: O
authors.initials: O
authors.lastname: Ishihara
authors.forename: N
authors.initials: N
authors.lastname: Hayashi
authors.forename: M
authors.initials: M
authors.lastname: Saitoh
authors.forename: J
authors.initials: J
authors.lastname: Taya
authors.forename: K
authors.initials: K
authors.lastname: Kinoshita
mesh_terms: D000328:Adult; D010064:Embryo Implantation; D004624:Embryo Transfer; D005260:Female; D005865:Gestational Age; D006801:Humans; D007247:Infertility, Female / Q000628:therapy*; D011247:Pregnancy; D011446:Prospective Studies; D014463:Ultrasonography; D014599:Uterus / Q000000981:diagnostic imaging*