Maternal plasma levels of cell-free β-HCG mRNA as a prenatal diagnostic indicator of placenta accrete

• We measured βHCG mRNA levels in 68 women with various types of placentation.
• The βHCG mRNA concentration is increased in women with placenta accreta.
• Women who underwent cesarean hysterectomy had markedly higher βHCG mRNA levels.
• Testing βHCG mRNA in maternal plasma may be useful for predicting placenta accreta.

ObjectiveSeveral biomarkers, including maternal serum creatinine kinase and α-fetoprotein, have been described as potential tools for the diagnosis of placental abnormalities. This study aimed to determine whether maternal plasma mRNA levels of the β subunit of human chorionic gonadotropin (β-HCG) could predict placenta accreta prenatally.MethodsSixty-eight singleton pregnant women with prior cesarean deliveries (CDs) were classified into three groups: normal placentation (35 women, control group); placenta previa alone (21 women, placenta previa group); and both placenta previa and placenta accreta (12 women, placenta previa/accreta group). Maternal plasma concentrations of cell-free β-HCG mRNA were measured by real-time reverse-transcription polymerase chain reaction and were expressed as multiples of the median (MoM).ResultsCell-free β-HCG mRNA concentrations (MoM, range) were significantly higher in women with placenta accreta (3.65, 2.78–7.19) than in women with placenta previa (0.94, 0.00–2.97) or normal placentation (1.00, 0.00–2.69) (Steel–Dwass test, P < 0.01 and P < 0.01, respectively). In the placenta previa/accreta group, the concentration of cell-free β-HCG mRNA was significantly higher among women who underwent CDs with hysterectomy (4.41, 3.49–7.19) than among women whose CDs did not result in hysterectomy (3.20, 2.78–3.70) (Mann–Whitney U test, P = 0.012).DiscussionAn increased level of cell-free β-HCG mRNA in the maternal plasma of women with placenta accreta may arise from direct uteroplacental transfer of cell-free placental mRNA molecules.ConclusionsThe concentration of cell-free β-HCG mRNA in maternal plasma may be applicable to the prenatal diagnosis of placenta accreta, especially to identify women with placenta accreta likely to require hysterectomy.