Abstract
Background Following the discovery that fetal DNA originates from the
trophoblastic cells of the placenta, the contribution of the cell-free DNA test
in placenta-related obstetric complications has begun to be investigated.
Compared to uncomplicated pregnancies, higher fetal fractions were detected in
placenta accreta spectrum and placenta previa, which are among placenta-related
obstetric complications. However, this data applies only to advanced gestational
weeks.
Aim To investigate the possible predictive value of fetal fraction in
cell-free DNA tests in pregnancies with placenta previa and placenta accreta
spectrum in early gestational ages.
Materials and Methods This study was conducted in women who were screened
via cell-free DNA tests for common aneuploidies in the first and second
trimester and subsequently diagnosed with placenta previa or placenta accreta
spectrum. After the diagnosis was confirmed with a C-section, fetal fractions
were retrospectively compared to a control group with a history of an
uncomplicated C-section who were also previously screened by cell-free DNA
test.
Results The median and interquartile range (IQR) of fetal fractions for
placenta previa (n=19), placenta accreta spectrum (n=7), and
control groups (n=85) were 8.1 (6–10), 6.8 (6.7–10.7),
and 7.1 (4.7–9.65), respectively. No statistically significant
difference was observed among the three groups in terms of fetal fractions
(p=0.587).
Conclusions According to our data, we did not observe any relationship
between placental invasion abnormalities vs. control group or placenta previa
vs. control group using the fetal fractions of the cell-free DNA test.
Furthermore, we could not confirm a predictive role and/or any
additional clinical contribution. We believe that future studies focusing on
placental mRNA might be more helpful than cell-free fetal DNA testing.
Key words
cell-free DNA test - fetal fraction - placenta accreta spectrum - placenta previa