First-trimester screening for trisomy 21 combining biochemistry and ultrasound at individually optimal gestational ages. An interventional study

Authors

  • Antoni Borrell,

    Corresponding author
    1. Prenatal Diagnosis Unit, Institute of Gynecology, Obstetrics and Neonatology, Hospital Clinic, University of Barcelona Medical School, Barcelona, Catalonia, Spain
    • Prenatal Diagnosis Unit, Institute of Gynecology, Obstetrics and Neonatology, Hospital Clinic, Seu Maternitat, Sabino de Arana 1, Barcelona 08028, Catalonia, Spain.
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  • Elena Casals,

    1. Department of Biochemistry, Biomedical Diagnosis Center, University of Barcelona Medical School, Barcelona, Catalonia, Spain
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  • Albert Fortuny,

    1. Prenatal Diagnosis Unit, Institute of Gynecology, Obstetrics and Neonatology, Hospital Clinic, University of Barcelona Medical School, Barcelona, Catalonia, Spain
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  • M. Teresa Farre,

    1. Prenatal Diagnosis Unit, Institute of Gynecology, Obstetrics and Neonatology, Hospital Clinic, University of Barcelona Medical School, Barcelona, Catalonia, Spain
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  • Anna Gonce,

    1. Prenatal Diagnosis Unit, Institute of Gynecology, Obstetrics and Neonatology, Hospital Clinic, University of Barcelona Medical School, Barcelona, Catalonia, Spain
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  • Aurora Sanchez,

    1. Prenatal Diagnosis Unit, Institute of Gynecology, Obstetrics and Neonatology, Hospital Clinic, University of Barcelona Medical School, Barcelona, Catalonia, Spain
    2. Genetics Service, Biomedical Diagnosis Center, Hospital Clinic, University of Barcelona Medical School, Barcelona, Catalonia, Spain
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  • Anna Soler,

    1. Genetics Service, Biomedical Diagnosis Center, Hospital Clinic, University of Barcelona Medical School, Barcelona, Catalonia, Spain
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  • Vicençc Cararach,

    1. Prenatal Diagnosis Unit, Institute of Gynecology, Obstetrics and Neonatology, Hospital Clinic, University of Barcelona Medical School, Barcelona, Catalonia, Spain
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  • Joan A. Vanrell

    1. Prenatal Diagnosis Unit, Institute of Gynecology, Obstetrics and Neonatology, Hospital Clinic, University of Barcelona Medical School, Barcelona, Catalonia, Spain
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Abstract

Objective

To assess the effectiveness of the Combined Test in the prenatal detection of trisomy 21 in the general pregnant population using a new timing for the screening approach.

Methods

First-trimester maternal serum biochemical markers (pregnancy-associated plasma protein-A and free-β hCG) were determined in maternal serum at 7 to 12 weeks. Fetal nuchal translucency and gestational age were assessed at the 10- to 14-week ultrasound scan. A combined risk was estimated and delivered to the women the same day. When the risk was 1:250 or above, chorionic villus sampling was offered.

Results

Mean gestational age at biochemistry was 9.4 weeks, being 12.3 at ultrasound. In the 2780 studied pregnancies with a complete follow-up, observed detection rates were 88% (7/8) for trisomy 21 and 75% (3/4) for trisomy 18, with a 3.3% (92/2765) false-positive rate.

Conclusion

The Combined Test, assessing biochemistry and ultrasound at individually optimal ages in the first trimester, showed an 88% detection rate for trisomy 21 with a remarkably reduced false-positive rate (3.3%). Copyright © 2004 John Wiley & Sons, Ltd.

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