Cell-Free Placental mRNA in Maternal Plasma to Predict Placental Invasion in Patients With Placenta Accreta

Abstract

The first-line methods used to diagnose placenta accreta are ultrasound and Doppler. A large number of studies have shown that their diagnostic accuracy is variable. Some investigators have suggested that placental messenger RNA (mRNA) may be a useful predictive marker for hysterectomy among patients with placenta previa associated with placenta accreta. This prospective study investigated whether the concentration of cell-free placental mRNA was a useful predictive marker for detection of placental invasion in women with placenta accreta and whether knowledge of the concentration could improve the diagnostic accuracy of ultrasound and color Doppler. The participants were 35 singleton pregnant women of more than 28 weeks' gestation who were at risk for placenta accreta. All study subjects underwent ultrasound and color Doppler assessment. The study was conducted at an antenatal care clinic at a university hospital in Egypt between 2007 and 2009. Maternal plasma concentrations of cell-free mRNA were measured using a one-step quantitative real-time reverse transcription polymerase chain reaction assay. Based on the cesarean and/or histological diagnosis, the study subjects were divided into 2 following groups: women with (n = 28) and without (n = 7) placenta accreta. The median MoM (multiples of the median) value of cell-free placental mRNA was calculated in both groups. Compared to women without placenta accreta, those with accreta had a significantly higher median MoM value of cell-free placental mRNA (6.50 vs. 2.60, P < 0.001). In addition, cell-free placental mRNA values were significantly higher among patients with placenta increta or percreta compared to those with simple accreta diagnosed at cesarean delivery (P < 0.002). Insignificant increases in cell-free placental mRNA levels were observed in 6 women with a false-positive diagnosis of placenta accreta on ultrasound. These findings suggest that measurement of cell-free placental mRNA in maternal plasma may increase the predictive diagnostic accuracy of ultrasound and color Doppler for placental invasion in pregnant women with suspected placenta accreta. However, the small sample size makes it difficult to draw a definite conclusion from this study.