Quantification of the placental epigenetic signature of the SERPINB5 gene in maternal plasma of pregnancies complicated by small for gestational age

Introduction To investigate the association between pregnancies with small for gestational age (SGA) neonates and the concentration of cell-free fetal DNA or cell-free total DNA in maternal plasma during the first and second trimesters using tissue-specific epigenetic characteristics of the SERPINB5 gene. Methods A nested case–control study was conducted with maternal plasma collected at 11 to 26 gestational weeks from 51 women with SGA neonates and 102 controls. We performed a real-time quantitative methylation-specific PCR to quantify concentrations of unmethylated- SERPINB5 (U- SERPINB5 ) as a cell-free fetal DNA marker and methylated- SERPINB5 (M- SERPINB5 ) as a cell-free total DNA marker. Results A positive correlation was observed between U- SERPINB5 and M- SERPINB5 concentrations in both control ( r = 0.363, p r = 0.548, p SERPINB5 or M- SERPINB5 was significantly positive correlated with gestational age at sampling in both controls (U- SERPINB5 : r = 0.397, p SERPINB5 : r = 0.275, p = 0.005) and SGA (U- SERPINB5 : r = 0.274, p = 0.052; M- SERPINB5 : r = 0.439, p = 0.001). However, the concentration of U- SERPINB5 or M- SERPINB5 was not correlated with birthweight. At 11–14 weeks, U- SERPINB5 and M- SERPINB5 concentrations in SGA did not differ significantly from those of controls. There were also no statistically significant differences in the concentrations of U- SERPINB5 and M- SERPINB5 between SGA and controls at 15–26 weeks of gestation. Discussion Our findings suggest that U- SERPINB5 and M- SERPINB5 concentrations in maternal plasma during early pregnancy are not associated with pregnancies who delivered SGA neonates.