title: [Results of prenatal screening for fetal chromosome abnormality during the first trimester pregnancy in Guangzhou].
abstract: OBJECTIVE
  To evaluate the efficiency of first trimester prenatal screening for fetal chromosome abnormality using maternal serum marker test and(or) plus nuchal translucency (NT) in Guangzhou region.
  
  
  METHODS
  The results of prenatal screening were retrospectively analyzed among 43 703 women with singleton pregnancies from January 2007 to September 2012. A total of 43 703 pregnancies between 9 and 13(+6) weeks of pregnancy were collected and analyzed for maternal serum pregnancy-associated plasma protein A (PAPPA), free β -human chorionic gonadotropin (free β -hCG) with or without crown-rump length (CRL). Nuchal translucency was measured by ultrasonographic scan between 11 and 13(+6) weeks of pregnancy. Gestational age was estimated by ultrasonographic scan. The risk values of Down syndrome (DS) and trisomy 18 were calculated using the software Lifcycle. Comparing the difference between the combined screening (PAPPA, free β -hCG and NT) and serum marker screening (PAPPA and free β -hCG).
  
  
  RESULTS
  Among the 43 703 pregnant women, screening showed that 1385 (3.17%) were Down syndrome positive and 55 (0.13%) were trisomy 18 positive. The final outcomes of pregnancy showed that 142 cases presented chromosomal abnormalities, of which 54 cases suffered from Down syndrome, 13 had trisomy 18, and 75 had other chromosome abnormalities. The total detection rate of Down syndrome and trisomy 18 were 83.33% and 76.92%, respectively.The positive rate is lower, and the detection rate is higher in combined screening group than serum marker screening group. The median PAPPA MoM was lower and the median free β -hCG MoM and NT measured value was higher in Down syndrome pregnancies than control group. The median PAPPA and free β -hCG MoM were lower and the median NT measured value was higher in trisomy 18 pregnancies than control group.
  
  
  CONCLUSIONS
  The first trimester prenatal screening can effectively detect Down syndrome and trisomy 18 pregnancy. The combined screening method is superior to the serum marker screening and is the preferred strategy in the first trimester prenatal screening.
authors.affiliation: Prenatal Diagnosis Center, Guangzhou Woman and Children's Medical Center, Guangzhou, Guangdong 510623, P.R.China. zunp_xu@163.com.
authors.forename: Zunpeng
authors.initials: Z
authors.lastname: Xu
authors.forename: Bei
authors.initials: B
authors.lastname: Li
authors.forename: Can
authors.initials: C
authors.lastname: Liao
authors.forename: Qian
authors.initials: Q
authors.lastname: Sun
authors.forename: Xue
authors.initials: X
authors.lastname: Bai
authors.forename: Dongzhi
authors.initials: D
authors.lastname: Li
mesh_terms: D000293:Adolescent; D000328:Adult; D044466:Asian People / Q000235:genetics; D015415:Biomarkers / Q000097:blood; D002681:China; D018997:Chorionic Gonadotropin, beta Subunit, Human / Q000097:blood; D025063:Chromosome Disorders / Q000175:diagnosis / Q000196:embryology / Q000235:genetics*; D002887:Chromosomes, Human, Pair 18 / Q000235:genetics; D004314:Down Syndrome / Q000175:diagnosis / Q000235:genetics; D005260:Female; D005315:Fetal Diseases / Q000175:diagnosis / Q000208:ethnology / Q000235:genetics*; D005820:Genetic Testing / Q000379:methods*; D006801:Humans; D008875:Middle Aged; D048208:Nuchal Translucency Measurement; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011266:Pregnancy-Associated Plasma Protein-A / Q000378:metabolism; D011296:Prenatal Diagnosis / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014314:Trisomy / Q000175:diagnosis / Q000235:genetics; D000073842:Trisomy 18 Syndrome; D055815:Young Adult
chemical_list: D015415:Biomarkers; D018997:Chorionic Gonadotropin, beta Subunit, Human; D011266:Pregnancy-Associated Plasma Protein-A