title: Predictive value of maternal serum human chorionic gonadotropin levels in pregnancies achieved by in vitro fertilization with single cleavage and single blastocyst embryo transfers.
abstract: OBJECTIVE
  To compare serum hCG levels after transfer of a single fresh cleavage embryo and of a single fresh blastocyst embryo and to determine the predictive value of serum hCG levels for pregnancy outcomes.
  
  
  METHODS
  A single center retrospective cohort study.
  
  
  METHODS
  Tertiary university health center.
  
  
  METHODS
  All fresh single ETs between December 2008 and December 2013.
  
  
  METHODS
  None.
  
  
  METHODS
  Mean serum hCG levels on day 16 after oocyte collection, after the transfer of a fresh single cleavage embryo and a fresh single blastocyst embryo were compared. Multivariable regression analysis was performed to determine the association of potential factors on hCG value and a clinical pregnancy.
  
  
  RESULTS
  One thousand twenty-six fresh single ETs were analyzed, 801 (638 pregnancies) from a single blastocyst transfer and 225 (167 pregnancies) from a single cleavage ET. The mean hCG levels resulting from a single fresh blastocyst transfer (299 ± 204 IU/L) were significantly higher than those from a cleavage transfer (245 ± 204 IU/L). This difference remained after adjusting for confounding variables. The threshold value predicting a clinical pregnancy for a cleavage embryo was 100 IU/L, and for a blastocyst transfer, 133 IU/L.
  
  
  CONCLUSIONS
  Our study suggests that initial serum hCG values are higher after the transfer of a single fresh blastocyst embryo compared with after a single fresh cleavage ET, even after adjusting for confounding variables.
authors.affiliation: Department of Obstetrics and Gynecology, McGill University, Montreal, Quebec, Canada. Electronic address: orongalia@gmail.com.
authors.forename: Galia
authors.initials: G
authors.lastname: Oron
authors.affiliation: Department of Obstetrics and Gynecology, McGill University, Montreal, Quebec, Canada.
authors.forename: Efrat
authors.initials: E
authors.lastname: Esh-Broder
authors.affiliation: Department of Obstetrics and Gynecology, McGill University, Montreal, Quebec, Canada.
authors.forename: Weon-Young
authors.initials: WY
authors.lastname: Son
authors.affiliation: Department of Obstetrics and Gynecology, McGill University, Montreal, Quebec, Canada.
authors.forename: Hananel
authors.initials: H
authors.lastname: Holzer
authors.affiliation: Department of Obstetrics and Gynecology, McGill University, Montreal, Quebec, Canada.
authors.forename: Togas
authors.initials: T
authors.lastname: Tulandi
mesh_terms: D000328:Adult; D006063:Chorionic Gonadotropin / Q000097:blood*; D002970:Cleavage Stage, Ovum / Q000378:metabolism; D015331:Cohort Studies; D004624:Embryo Transfer / Q000706:statistics & numerical data*; D005260:Female; D005307:Fertilization in Vitro / Q000706:statistics & numerical data*; D006801:Humans; D007247:Infertility, Female / Q000097:blood / Q000453:epidemiology* / Q000628:therapy*; D050498:Live Birth / Q000453:epidemiology*; D011247:Pregnancy / Q000097:blood*; D015995:Prevalence; D011379:Prognosis; D011792:Quebec / Q000453:epidemiology; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D016896:Treatment Outcome
chemical_list: D006063:Chorionic Gonadotropin
keywords: blastocyst; cleavage; hCG; pregnancy; single embryo transfer