title: Maternal age and serum concentration of human chorionic gonadotropin in early pregnancy.
abstract: OBJECTIVE
  To study whether maternal age is associated with serum concentration of human chorionic gonadotropin in early pregnancy.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  Oslo University Hospital in Oslo, Norway.
  
  
  METHODS
  All vital pregnancies in gestational week 8 conceived by in vitro fertilization between February 1996 and February 2013 (n = 4472).
  
  
  METHODS
  Serum concentrations of human chorionic gonadotropin were measured on day 12 after embryo transfer/day 16 following ovulation induction. Trends in geometric means of human chorionic gonadotropin concentrations by maternal age group were tested by linear regression analysis. We also studied the association of maternal age (years) with log-transformed human chorionic gonadotropin concentrations, and adjustments were made for number of embryos transferred, method of in vitro fertilization and year (period) of embryo transfer.
  
  
  METHODS
  Serum concentration of human chorionic gonadotropin.
  
  
  RESULTS
  Geometric mean concentrations of human chorionic gonadotropin decreased with increasing maternal age (p = 0.024, test for trend by weighted linear regression). Also, we estimated a significant negative association of maternal age with log-transformed human chorionic gonadotropin concentrations (adjusted regression coefficient -0.011, standard error 0.003, p < 0.001).
  
  
  CONCLUSIONS
  Serum concentrations of human chorionic gonadotropin in very early pregnancy decreased with maternal age. Since human chorionic gonadotropin is synthesized in trophoblast cells only, the lower human chorionic gonadotropin concentrations in women of advanced age may reflect functional impairment or delayed proliferation of trophoblast cells in early pregnancy in these women.
authors.affiliation: Department of Gynecology and Obstetrics, Akershus University Hospital, Lørenskog, Norway; Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
authors.forename: Camilla
authors.initials: C
authors.lastname: Haavaldsen
authors.forename: Peter
authors.initials: P
authors.lastname: Fedorcsak
authors.forename: Tom
authors.initials: T
authors.lastname: Tanbo
authors.forename: Anne
authors.initials: A
authors.lastname: Eskild
mesh_terms: D000367:Age Factors; D018997:Chorionic Gonadotropin, beta Subunit, Human / Q000097:blood*; D003430:Cross-Sectional Studies; D010064:Embryo Implantation / Q000502:physiology; D004624:Embryo Transfer; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D008423:Maternal Age; D009664:Norway / Q000453:epidemiology; D011247:Pregnancy; D011261:Pregnancy Trimester, First / Q000097:blood*; D012044:Regression Analysis
chemical_list: D018997:Chorionic Gonadotropin, beta Subunit, Human
keywords: Human chorionic gonadotropin; in vitro fertilization; maternal age; pregnancy; reproductive endocrinology