title: First-trimester combined screening for trisomy 21 in women at risk for α-thalassemia.
abstract: OBJECTIVE
  To report the strategy of first-trimester aneuploidy screening in pregnancies at risk for homozygous α(0)-thalassemian.
  
  
  METHODS
  Women at risk of homozygous α(0)-thalassemia were given an ultrasound examination at 11-14 weeks' gestation to exclude an affected pregnancy. Fetal cardiothoracic ratio (CTR) and nuchal translucence (NT) were measured. If cardiomegaly was found, chorionic villus sampling (CVS) was offered for α-thalassemia; otherwise the first-trimester combined screening test was performed on the pregnancy. The invasive testing for karyotyping was only followed in those cases with a positive aneuploidy screening test.
  
  
  RESULTS
  In total, 69 of 288 pregnancies were found to be affected by homozygous α(0)-thalassemia using ultrasound, and the findings were confirmed by invasive testing. In the remaining 219 pregnancies, invasive testing was not performed for α-thalassemia because of a normal fetal CTR, and the women received the first-trimester combined screening. Nine CVS procedures were performed for karyotyping because of a positive aneuploidy screening. Totally three pregnancies with aneuploidy were diagnosed and terminated.
  
  
  CONCLUSIONS
  Our strategy can selectively detect aneuploidy pregnancies not affected by homozygous α-thalassemia, and, meanwhile, save on the cost of unnecessary aneuploidy screening or karyotyping in pregnancies with an affected fetus of homozygous α(0)-thalassemia.
authors.affiliation: a Prenatal Diagnostic Center, Guangzhou Women and Children Medical Center Affiliated to Guangzhou Medical University , Guangzhou , Guangdong , China.
authors.forename: Li
authors.initials: L
authors.lastname: Zhen
authors.affiliation: a Prenatal Diagnostic Center, Guangzhou Women and Children Medical Center Affiliated to Guangzhou Medical University , Guangzhou , Guangdong , China.
authors.forename: Min
authors.initials: M
authors.lastname: Pan
authors.affiliation: a Prenatal Diagnostic Center, Guangzhou Women and Children Medical Center Affiliated to Guangzhou Medical University , Guangzhou , Guangdong , China.
authors.forename: Jin
authors.initials: J
authors.lastname: Han
authors.affiliation: a Prenatal Diagnostic Center, Guangzhou Women and Children Medical Center Affiliated to Guangzhou Medical University , Guangzhou , Guangdong , China.
authors.forename: Xin
authors.initials: X
authors.lastname: Yang
authors.affiliation: a Prenatal Diagnostic Center, Guangzhou Women and Children Medical Center Affiliated to Guangzhou Medical University , Guangzhou , Guangdong , China.
authors.forename: Can
authors.initials: C
authors.lastname: Liao
authors.affiliation: a Prenatal Diagnostic Center, Guangzhou Women and Children Medical Center Affiliated to Guangzhou Medical University , Guangzhou , Guangdong , China.
authors.forename: Dong-Zhi
authors.initials: DZ
authors.lastname: Li
mesh_terms: D000465:Algorithms; D000782:Aneuploidy; D004314:Down Syndrome / Q000175:diagnosis*; D005260:Female; D006801:Humans; D008403:Mass Screening; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011296:Prenatal Diagnosis / Q000706:statistics & numerical data*; D017085:alpha-Thalassemia / Q000175:diagnosis*
keywords: aneuploidy; cardiomegaly; prenatal screening; prenatal ultrasonography; α0-thalassemia