title: Maternal age and initial β-hCG levels predict pregnancy outcome after single vitrified-warmed blastocyst transfer.
abstract: OBJECTIVE
  We retrospectively examined a large cohort of females who underwent single blastocyst transfer to determine if initial β-human chorionic gonadotrophin (β-hCG) levels on day 7 after single vitrified-warmed blastocyst transfer (SVBT) could be used to predict pregnancy outcome.
  
  
  METHODS
  The treatment cycles that gave rise to the early pregnancies included in this study were performed from 2004 to 2011 in a private infertility center. In SVBT cycles, embryos were transferred during a natural cycle or after endometrial preparation with exogenous estrogen and progesterone. A total of 11,458 cycles with β-hCG levels ≥1.0 UI/ml on day 7 after SVBT were evaluated. The proportion of live births per positive β-hCG cycle was established for 10 β-hCG ranges in 3 different age groups (Group A: 21-34 years old; Group B: 35-39 years old; Group C: 40-44 years old).
  
  
  RESULTS
  The proportion of live births gradually increased from 1.5 to 93.7%, 0.8 to 87.9%, and 0.6 to 76.2% in Groups A, B, and C, respectively. For each range of β-hCG levels, the proportion of live births was higher for the younger age group, which reflected the increased risk of early pregnancy loss with advancing female age.
  
  
  CONCLUSIONS
  β-hCG levels on day 7 after SVBT, in conjunction with maternal age, may be used to predict pregnancy outcomes.
authors.affiliation: Kato Ladies Clinic, 7-20-3 Nishi-shinjuku, Shinjuku, Tokyo, 160-0023, Japan, scsosob@gmail.com.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Ueno
authors.forename: Kenji
authors.initials: K
authors.lastname: Ezoe
authors.forename: Takashi
authors.initials: T
authors.lastname: Abe
authors.forename: Akiko
authors.initials: A
authors.lastname: Yabuuchi
authors.forename: Kazuo
authors.initials: K
authors.lastname: Uchiyama
authors.forename: Takashi
authors.initials: T
authors.lastname: Okuno
authors.forename: Tamotsu
authors.initials: T
authors.lastname: Kobayashi
authors.forename: Keiichi
authors.initials: K
authors.lastname: Kato
mesh_terms: D000328:Adult; D018997:Chorionic Gonadotropin, beta Subunit, Human / Q000097:blood*; D004624:Embryo Transfer; D005260:Female; D006801:Humans; D008423:Maternal Age; D011247:Pregnancy; D011256:Pregnancy Outcome; D012189:Retrospective Studies; D058989:Vitrification
chemical_list: D018997:Chorionic Gonadotropin, beta Subunit, Human