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PrenaTest® is now validated
for multiple pregnancies
PrenaTest®, Europe‘s first molecular genetic, non-invasive prenatal test (NIPT)
for detection of fetal trisomies 13, 18 and 21 using maternal blood has
already been successfully used with thousands of singleton pregnancies. It
has now been successfully approved as the only NIPT in the EU for testing
of multiple pregnancies and can also be used without restriction following egg
donations or other therapy methods within assisted reproductive technologies
(ART).
Demographic development in Germany has been heading for many years toward an ever-increasing number of twin pregnancies, conditioned by the increasing age of the mother and the
growing use of assisted reproductive technology. In multiple pregnancies, the invasive diagnostic
method (amniocentesis) carries the burden of a markedly higher risk of abortion [3, 4] and
first-trimester screenings have a false-positive rate (FPR) that is two to three times higher than
that of single pregnancies [5]. Thus, the PrenaTest ® offers valuable improvement to pregnant
women, especially in the case of multiple pregnancies, by reducing the FPR to below one
percent, in line with expectations, as compared to first trimester screenings in which the FPR
for twins is between 10 – 15 % [5]. As a result, many women with twin pregnancies can circumvent an invasive diagnostic method and the associated intervention-related risks.
PrenaTest® reliably detects trisomy 21 in twin pregnancies
The use of NIPT in more than 3000 multiple pregnancies has confirmed that this method can
deliver results for the detection of fetal trisomies 21, 18 and 13 that are as equally reliable as
the results for singleton pregnancies [1, 2]. A total of 60 twin pregnancies and two triplet pregnancies were tested at LifeCodexx as part of the performance evaluation for the PrenaTest®. The
six cases of trisomy 21 found among the twin pregnancies and confirmed through karyotyping,
were correctly classified. Among these, one sample pertained to monochorial twins, each of
which had trisomy 21. The other five samples originated from dichorial twins, for which one
fetus in each pair was the carrier of the trisomy 21. The remaining multiple pregnancy samples
yielded unremarkable PrenaTest® results.
LifeCodexx AG Jakob-Stadler-Platz 7, 78467 Konstanz, Germany
Telephone +49 (0) 7531-9769460, Fax +49 (0) 7531-9769480, [email protected], www.lifecodexx.com
Newsletter February 2014
Dr. Markus Weber
Obstetrician/Gynecologist, Practice for Prenatal
Medicine (DEGUM II), Steinfurt, Germany
Percentage of cell-free fetal DNA (cffDNA) in the maternal blood is elevated among
multiple pregnancies
In general, the test accuracy of all NIPT methods is dependent on the content of cffDNA in
the maternal blood. The cffDNA is released from the placenta into the maternal blood. The
percentage increases as the pregnancy progresses and the placenta grows. In the case of
single pregnancies, LifeCodexx requires a minimum content of 4 % cffDNA which is generally
already achieved during week 9+0 of pregnancy. In the case of twin pregnancies, LifeCodexx
specifies a minimum content of 8 % cffDNA. Since a higher placenta mass is observed
overall in twin pregnancies as compared to single pregnancies, and is thus accompanied by
an approx. 35 % higher cffDNA content [1], it may be assumed that a cffDNA content of
8 % is already achieved early on in a twin pregnancy.
Sample depiction of the cffDNA content in 36 twin pregnancies, as a function of the pregnancy week. A content of 8 %
may already be present starting at week 9+0 of pregnancy.
cffDNA [%]
[2] Bombard AT, McCullough RM, Hicks SC et al.
Noninvasive prenatal testing (NIPT) in multiple
gestations: A report of laboratory experience.
Presented at: 61st American College of
Obstetricians & Gynecologists Annual Meeting.
New Orleans, LA, USA, May 4th to May 8th 2013
[3] DudenhausenW, Maier RF. Perinatale Probleme
von Mehrlingen.
Dtsch Arztebl Int 107(38):663-668 (2010)
[4] Agarwal K, Alfirevic Z. Pregnancy loss after
chorionic villus sampling and genetic amniocentesis in twin pregnancies: a systematic review.
Ultrasound Obstet Gynecol 40:128-134 (2012)
[5] Nicolaides K, von Kaisenberg CS. Die Ultraschalluntersuchung von 11-13+6 Schwangerschaftswochen. http://www.fetalmedicine.com/fmf/
FMF-german.pdf (last access Jan. 13, 2014)
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[6] Pursuant to the German IVF Register in 2006,
1625 twin births from a total of 10,538 twin
births in Germany in 2006, according to the
Federal Statistics Office
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pregnancy week
PrenaTest® as the only NIPT, even for reproductive medicine procedures incl. donor eggs
The percentage of twins who are born through reproductive measures is significant. In 2006,
this percentage was 15.4 % of all twins born in Germany [6], for example. Of all multiple
pregnancies examined by Life Codexx, 37.5 % occurred through in-vitro fertilisation (IVF).
One of the pregnancies tested was made possible through a donor egg, another one with
cryopreservation, all of which presented no limitations in terms of the applicability of the
PrenaTest ®. Thus, the PrenaTest ® is the only NIPT in the EU that can be used following all
reproductive medicine procedures.
Analysis for triplet or other multiple pregnancies
LifeCodexx also analyses samples for triplet or other multiple pregnancies. Since the amount
of data existing to date is not yet sufficient for a validation, we are preliminarily offering this
analysis free of charge as part of our research and development work. Please contact us in
such a case.
WM-1082-EN-001 / February 2014
[1] Canick JA, Kloza EM, Lambert-Messerlian GM
et al. DNA sequencing of maternal plasma to
identify Down syndrome and other trisomies
in multiple gestations. Prenat. Diagn. 32(8),
730-734 (2012).