title: [First trimester and second-trimester integrated screening for Down's syndrome].
abstract: OBJECTIVE
  To evaluate the effect of first and second-trimester integrated screening so as to provide an efficient screening protocol for Down's syndrome.
  
  
  METHODS
  Using the dissociation-enhanced lanthanide fluorescent immunoassay (DELFIA), the freeβhCG (beta human chorionic gonadotropin), PAPP-A (pregnancy associated plasma protein-A) and NT (nuchal translucency) value of type B ultrasound were assayed in the pregnancy serum during the first trimester (11-13W(+6) d) and free βhCG and AFP (alpha fetoprotein) during the second trimester(15-20W(+6) d). By the risk calculation software, the risks during both trimesters and their integrated risk were calculated for each patient respectively. Amniocentesis and venepuncture were employed for diagnosing the high-risk patients (> 1/270). Electronic network follow-up was carried out after delivery.
  
  
  RESULTS
  In a total of 4237 pregnant women, 98 were found to carry a high risk during the first trimester, 241 during the second trimester and 101 during the integrated screening respectively. And 2, 3 and 4 cases were diagnosed with Down's symptom at a detection rate of 50%, 75% and 100% and a detection efficiency of 1:50, 1:80 and 1:25 respectively.
  
  
  CONCLUSIONS
  Integrated screening is superior to either the first or second-trimester screening. With a lower false positive rate and a higher detection rate, it reduces the chance of invasive puncture. Advanced type B ultrasonic technology is needed to improve the first-trimester diagnostic efficiency and to develop a better integrated screening protocol.
authors.affiliation: Center of Prenatal Diagnosis, Maternity & Children Health Hospital of Jiaxing, Medical School of Jiaxing College, Jiaxing 314050, China.
authors.forename: Zheng-you
authors.initials: ZY
authors.lastname: Miao
authors.forename: Xia
authors.initials: X
authors.lastname: Liu
authors.forename: Tong-kun
authors.initials: TK
authors.lastname: Shi
authors.forename: Jia-mei
authors.initials: JM
authors.lastname: Ge
authors.forename: Ying
authors.initials: Y
authors.lastname: Xu
mesh_terms: D000328:Adult; D004314:Down Syndrome / Q000175:diagnosis* / Q000517:prevention & control*; D005260:Female; D006801:Humans; D048208:Nuchal Translucency Measurement; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011262:Pregnancy Trimester, Second; D011296:Prenatal Diagnosis