Objective: To evaluate (1) whether the presence of mRNA for the specific trophoblast gene PLAC1 in maternal whole blood is pregnancy-specific, and (2) whether delivery would result in the clearance of mRNA from maternal blood.
Methods: Sixteen pregnant women at term (41 completed weeks' gestation) were enrolled in the study. Blood samples were obtained before the onset of labor and 24 h after delivery. Eight healthy donors (3 males and 5 non-pregnant women) were used as controls. Total RNA was extracted by means of ABI Prism 6100. A quantitative evaluation was obtained by means of real-time PCR. Wilcoxon test was used to evaluate differences between time intervals.
Results: Median concentrations of PLAC1 mRNA relative to the standardization curve (see below) were 44 (2.9-675) ng/ml and 0.48 (0.05-10.7) ng/ml respectively for pre- and post-delivery samples (p value <0.001). Male and non-pregnant female controls did not show any signal of cDNA amplification.
Conclusion: mRNA transcripts from a placenta-expressed specific gene are detectable in maternal blood and rapidly disappear after delivery. Such an mRNA provides a gender-independent marker for non-invasive prenatal gene expression profiling, and can open new perspectives to monitor those conditions associated to trophoblast damage as well as preeclampsia.