title: [Establishment of median values for second trimester maternal serum biomarkers in Weihai region].
abstract: OBJECTIVE
  To establish the median values for second trimester biomarkers in Weihai region, and to assess its value for improving the performance and efficiency of prenatal screening.
  
  
  METHODS
  Maternal serum alpha-fetoprotein (AFP) and free beta human chorionic gonadotropin (Free beta-hCG) were determined for 24 400 pregnant women at 105 to 146 gestational days. A regression equation was derived after adjusting for different gestational ages. The median values were further adjusted with body weight.
  
  
  RESULTS
  The median values of AFP and Free beta-hCG were respectively 6% and 24% higher than those embedded in a 2T software. After adjusting with gestational age and weight, there is a significant difference in multiple of the median (MoM) of serum biomarkers between local population and that embedded in the 2T model.
  
  
  CONCLUSIONS
  To establish the median values for different gestational ages for local region may help to improve the efficiency of prenatal screening.
authors.affiliation: Weihai Maternal and Child Hospital, Weihai, Shandong 264200, P R China. xinqiangl@126.com
authors.forename: Xin-qiang
authors.initials: XQ
authors.lastname: Lan
authors.forename: Shu-hui
authors.initials: SH
authors.lastname: Wang
authors.forename: Yu-zhi
authors.initials: YZ
authors.lastname: Deng
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood*; D018997:Chorionic Gonadotropin, beta Subunit, Human / Q000097:blood; D005260:Female; D006801:Humans; D011247:Pregnancy; D011256:Pregnancy Outcome; D011262:Pregnancy Trimester, Second / Q000097:blood*; D012016:Reference Values; D055815:Young Adult
chemical_list: D015415:Biomarkers; D018997:Chorionic Gonadotropin, beta Subunit, Human