title: Occult abnormal pregnancies after first post-embryo transfer serum beta-human chorionic gonadotropin levels of 1.0-5.0 mIU/mL.
abstract: OBJECTIVE
  To assess the occult pregnancy rate after "negative" first post-embryo transfer (ET) serum β-hCG results.
  
  
  METHODS
  Two-part retrospective cohort study and nested case series.
  
  
  METHODS
  University-based fertility center.
  
  
  METHODS
  A total of 1,571 negative first post-ET serum β-hCG results were included in the study; 1,326 results (primary cohort, June 2009-December 2013) were initially reported as <5 mIU/mL and 245 results (secondary cohort, January 2014-March 2015) were reported as discrete values from 1.0 to 5.0 mIU/mL.
  
  
  METHODS
  None.
  
  
  METHODS
  Rates of occult pregnancy, ectopic pregnancy, and complications after negative first post-ET serum β-hCG results.
  
  
  RESULTS
  A total of 88.8% (1,178/1,326) of the negative first post-ET results reported as <5 were actually <1.0 mIU/mL. Occult pregnancy was incidentally identified in 1.2% (12/1,041) of subjects with follow-up. Six had ectopic pregnancies, and seven experienced serious complications; 11 (91.7%) of the 12 occult pregnancies had a first post-ET serum β-hCG level of 1.0-5.0 mIU/mL and 1 (8.3%) <1.0 mIU/mL. All pregnancies with serious complications had initial β-hCG levels of 1.0-5.0 mIU/mL. Of the 245 results reported as discreet values, occult pregnancies were diagnosed in 5.5% (9/163) of subjects with follow-up. One had an ectopic pregnancy, which was treated with methotrexate. There were no serious complications in the secondary cohort.
  
  
  CONCLUSIONS
  The majority of negative first post-ET serum β-hCG levels are <1.0 mIU/mL. Results from 1.0 to 5.0 mIU/mL may fail to exclude abnormal pregnancy and are associated with poor outcomes compared with β-hCG levels <1.0 mIU/mL. Serial serum β-hCG may be warranted in this population.
authors.affiliation: Division of Reproductive Endocrinology and Infertility, University of Connecticut School of Medicine, Farmington, Connecticut.
authors.forename: Bat-Sheva L
authors.initials: BS
authors.lastname: Maslow
authors.affiliation: Division of Reproductive Endocrinology and Infertility, University of Connecticut School of Medicine, Farmington, Connecticut.
authors.forename: Alison
authors.initials: A
authors.lastname: Bartolucci
authors.affiliation: Division of Reproductive Endocrinology and Infertility, University of Connecticut School of Medicine, Farmington, Connecticut.
authors.forename: Carolina
authors.initials: C
authors.lastname: Sueldo
authors.affiliation: Division of Reproductive Endocrinology and Infertility, University of Connecticut School of Medicine, Farmington, Connecticut.
authors.forename: Lawrence
authors.initials: L
authors.lastname: Engmann
authors.affiliation: Division of Reproductive Endocrinology and Infertility, University of Connecticut School of Medicine, Farmington, Connecticut.
authors.forename: Claudio
authors.initials: C
authors.lastname: Benadiva
authors.affiliation: Division of Reproductive Endocrinology and Infertility, University of Connecticut School of Medicine, Farmington, Connecticut. Electronic address: nulsen@uchc.edu.
authors.forename: John C
authors.initials: JC
authors.lastname: Nulsen
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D018997:Chorionic Gonadotropin, beta Subunit, Human / Q000097:blood*; D015331:Cohort Studies; D004624:Embryo Transfer / Q000639:trends*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D011247:Pregnancy; D011248:Pregnancy Complications / Q000097:blood* / Q000175:diagnosis* / Q000453:epidemiology; D011271:Pregnancy, Ectopic / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology; D012189:Retrospective Studies
chemical_list: D015415:Biomarkers; D018997:Chorionic Gonadotropin, beta Subunit, Human
keywords: Ectopic pregnancy; in vitro fertilization; serum β-hCG