Screening for Common Fetal Trisomies in Twin Pregnancies: First-Trimester Combined, Cell-Free DNA, or Both?

Lucia Pasquini, Ilaria Ponziani, Enrico Periti, Laura Marchi, Carlo Luchi, Veronica Accurti, Francesco D'Ambrosi, Nicola Persico

Research output: Contribution to journalArticlepeer-review


Objective: To examine the distribution of risks for fetal trisomies after first-trimester combined screening in twins and to investigate different strategies for clinical implementation of cell-free DNA (cfDNA) testing. Methods: We retrospectively analyzed all twin pregnancies undergoing first-trimester combined screening over a 10 years' period. The population was stratified according to various risk cut-offs, and we examined different screening strategies for implementation of cfDNA testing in terms of impact on invasive testing rate, cfDNA test failure rate, and economic costs. Results: We included 572 twin pregnancies: 480 (83.92%) dichorionic and 92 (16.08%) monochorionic. Performing a first-line combined screening and offering cfDNA testing to the group with a risk between 1 in 10 and 1 in 1,000, would lead to an invasive testing rate of 2.45%, and cfDNA testing would be performed in 22.20% of the population. This strategy would be cost-neutral compared to universal combined screening alone. Conclusions: First-trimester combined screening results can be used to stratify twin pregnancies into different risk categories and select those that could be offered cfDNA testing. A contingent screening strategy would substantially decrease the need for invasive testing in twins and it would be cost-neutral compared to combined testing alone.

Original languageEnglish
Pages (from-to)217–222
JournalFetal Diagnosis and Therapy
Issue number4
Publication statusPublished - 2019


  • Cell-free DNA
  • Chromosomal abnormalities
  • Combined test
  • First-trimester screening
  • Twin pregnancies

ASJC Scopus subject areas

  • Pediatrics, Perinatology, and Child Health
  • Embryology
  • Radiology Nuclear Medicine and imaging
  • Obstetrics and Gynaecology


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