The introduction of cell-free DNA based prenatal screening (NIPT) in 2011 led to a huge improvement in specificity of prenatal screening for the three most frequent chromosomal aneuploidies (trisomies 21, 18 and 13) and also improved their detection rates. This enabled a vast reduction in number of post-screening counselling consultations and invasive test procedures.

National Screening Programs are in place in a number of European countries. Some countries offer NIPT to all pregnant women and other countries offer NIPT as a secondary test to women with an elevated risk based on first trimester combined test results or other risk indicating parameters.

Targeted NIPT technologies allow to test for the most frequent aneuploidies and eventually selected microdeletions. Whole-Genome Sequencing (WGS) based NIPT to the contrary allows to also report on aneuploidies on the other chromosomes and on large partial deletions and duplications, also called copy number variations (CNVs).

Paired end sequencing is an important feature of WGS-based NIPT because it allows for more efficient alignment of fragments on the reference genome and because it adds to the parameters for measuring fetal fraction (FF). The ability to measure FF is an important quality parameter and should be a factor in choosing an NIPT provider.

Reporting chromosome anomalies beyond the three most frequent aneuploidies allows detection of additional fetal anomalies, even in the absence of ultrasound anomalies. Second, it helps identify at risk pregnancies that can benefit from altered management. Third, it can take away the uncertainty related to unexplained adverse outcomes such as miscarriage and allows for better recurrence risk counselling. Finally, it will promote understanding of the effect of confined placental mosaicism on fetal health and wellbeing.

Dr. Lieve Page-Christiaens Associate Director, Medical Affairs, Illumina

Lieve Christiaens joined Illumina in 2016 as an Associate Medical Director and was successively part of the Market Development Team, the Scientific Affairs Team and the Medical Affairs Team. Before 2016 was a Fetal Maternal Medicine specialist with special focus on Perinatal Genetics for most of her professional life. She was an Associate Professor at the University Hospital of Utrecht in the Netherlands. She was a Chair or Member of a number of Advisory Boards of the Dutch Health Council, advising the Minister of Health on Prenatal Screening, Preimplantation Genetic Diagnosis, Newborn Screening and Neonatal Intensive Care. In these and other functions she was involved in National Policy making around Reproductive Genetics. She was also involved, either as a Committee Chair or as a Member, in monitoring National Prenatal and Newborn Screening Programs coordinated by the National Institute for Public Health and the Environment, an agency of the Netherlands Ministry of Health, Welfare and Sport. She supervised 7 PhD theses, (co)authored over 150 papers and over 40 book chapters, mainly in the field of perinatal genetics and immunohaematology, and was the main editor of the first book on NIPT “Noninvasive Prenatal Testing (NIPT) – Applied Genomics in Prenatal Screening and Diagnosis” published by Elsevier in September 2018.