Total and Fetal Cell-Free DNA Analysis in Maternal Blood as Markers of Placental Insufficiency in Intrauterine Growth Restriction

Abstract

Objective: To compare total and fetal DNA levels in the maternal plasma in three groups: pregnancies with intrauterine growth restriction (IUGR) due to placental insufficiency (PI) and other causes, and in control pregnancies. Methods: Total as well as fetal DNA was quantified in 78 maternal plasma samples. In 19 pregnancies, the fetus presented IUGR due to PI (group A), and in 31 pregnancies due to other causes (group B). The control group comprised 28 patients (group C). DNA quantification was done using real-time quantitative PCR with a standardized pool of plasmid calibrators. DNA concentrations of the three groups were compared using non-parametric tests (Kruskal-Wallis or Mann-Whitney tests). Results: The three groups did not statistically differ regarding maternal age (mean ± SD: 30.5 ± 5.4 years), gestational age (30 ± 5.3 weeks) or the proportion of male fetuses (48.2%). Plasma total DNA was significantly higher in group A compared to groups B and C (p = 0.001 for both). An increase in fetal DNA was only observed in group A for patients beyond 28 weeks of gestation. Conclusions: The plasma total DNA level is higher in patients with IUGR due to PI. These results suggest the presence of maternal endothelial damage independently of preeclampsia.

Cell-Free Placental DNA in Maternal Plasma in Relation to Placental Health and Function

“…Distinguishing the cause of IUGR is likely important, as an increase of cfp-DNA levels was previously observed only for those IUGR cases associated with PE [37] . In cases of IUGR in twins, the cfp-DNA level was increased consistent with a cumulative effect of multiple gestations [27] and, possibly, placental lesions [38] .…”

“…Besides the high variability of controls, nondiscriminatory levels of cfp-DNA in GH cases can also be explained by (i) a nonlinear elevation before onset of symptoms [35,36] and (ii) different levels of elevation in different subtypes of PE [26,37] .…”

Noninvasive nucleic acid–based approaches to monitor placental health and predict pregnancy-related complications

“…The cfp-DNA levels in IUGR were found to be either normal or increased but to a lesser extent than early-onset PE. 51, [85][86][87] Moreover, when IUGR cases were subdivided according to the presence or absence of PE, only the PE-related IUGR group revealed a significant cfp-DNA increase. 85 Increased FLT-1 protein level in placenta and maternal blood is well established to be associated with PE and IUGR.…”

“…51, [85][86][87] Moreover, when IUGR cases were subdivided according to the presence or absence of PE, only the PE-related IUGR group revealed a significant cfp-DNA increase. 85 Increased FLT-1 protein level in placenta and maternal blood is well established to be associated with PE and IUGR. Likewise, increased FLT-1 mRNA was detected in the plasma of nonhypertensive women with IUGR fetuses (<2 SD of mean fetus size) as early as the first trimester.…”

Circulating cell-free DNA concentration and DNase I activity of peripheral blood plasma change in case of pregnancy with intrauterine growth restriction compared to normal pregnancy

“…In the first research (16), authors did not find any discrepancy between cfDNA concentrations in cases of normal pregnancies and the ones with IUGR. Later studies indicated that cfDNA concentrations are increased in cases of pregnancies with IUGR (18)(19)(20)(21). It is of importance that in these studies the authors did not take into account the processes of elimination of cfDNA from plasma.…”