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Updated: Apr 7, 2026
Pre-Implantation Genetic Testing for Aneuploidy on a Semiconductor Based Next-Generation Sequencing Platform
Published on: August 17, 2022
First-trimester combined screening for trisomy 21 in women at risk for α-thalassemia
1a Prenatal Diagnostic Center, Guangzhou Women and Children Medical Center Affiliated to Guangzhou Medical University , Guangzhou , Guangdong , China.
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.
