beta-globin DNA in maternal plasma as a molecular marker of pre-eclampsia

Objectives: Levels of cell-free foetal DNA in maternal plasma are higher in the presence of clinical features of pre-eclampsia (PE). However, currently, this method is informative only in women bearing a male foetus, by amplification of Y-specific sequences. In the present study, we overcame this limitation by examining quantitative distribution of beta-globin, a foetal gender-independent DNA marker.

Methods: We quantified beta-globin concentrations in the plasma of 207 pregnant women: control group, 164 subjects; affected group, 43 women affected by PE (n = 43). beta-globin concentrations were converted into multiples of the median of the controls (MoM), in order to assess the possible different distribution of beta-globin MoM in cases and controls.

Results: Adjusted MoM values were as follows: controls, 1.00 +/- 0.71; affected group 4.03 +/- 3.77 (p-value < 0.001). Among the PE affected cases, MoM beta-globin values of cases with foetal growth restriction (FGR) were almost twice as great as those cases without FGR (p-value = 0.003).

Conclusion: beta-globin levels are higher in the plasma of pregnant women with PE, especially in those cases complicated with FGR, and do not depend on foetal gender. Such a molecular marker can potentially be used in evaluating the pathophysiological severity of PE.