Significant correlation between maternal body mass index at delivery and second trimester circulating total cell-free DNA levels

Objectives:

The ability to reliably identify and quantify cell-free fetal (cff) DNA in maternal circulation has substantially increased the clinical application of noninvasive prenatal diagnosis. However, the clinical use of cff DNA and its interpretation requires the knowledge of important clinical variables. We hypothesized that cff and total cell-free DNA in maternal plasma may be correlated with maternal body mass index (BMI) and its change during pregnancy.

Material and methods:

In this study, using four hundred and six maternal blood samples from the second trimester of pregnancy, circulating fetal DNA in maternal plasma samples, specific for the SRY and DYS14 loci (representing fetal DNA) and GAPDH sequence (representing total genomic DNA) were quantified by real-time PCR.

Results:

Fetal sex determination was 100% accurate using a combination of probes for SRY and DYS14. The levels of DYS14 and SRY detected were significantly correlated (r=0.73, p<0.001). No significant correlation was seen between the quantitative levels of cell-free male DNA and maternal BMI, whereas total cell-free DNA, was significantly associated with maternal body mass index at the end of pregnancy (r2: 0.016, p=0.014)

Conclusion:

Quantitative levels of fetal DNA are not affected by maternal BMI and its changes during pregnancy, whereas total DNA levels in the second trimester significantly correlates with maternal BMI at delivery.

biomarker - body mass index - cell-free fetal DNA - obstetrics