Correlation between Fetal Circulation and Growth in the Second Trimester

  Objective  To explore the relationship among the hemodynamic parameters of middle cerebral artery (MCA), umbilical artery (UmA), and uterine artery (UtA) and fetal growth in the second trimester.

  Methods  From June 2011 to July 2012, a total of 206 normal pregnant women with a gestation age of 20-24⁺⁶ weeks were examined by color Doppler ultrasound after routine screening scanning. The anatomic parameters including biparietal diameter (BPD), head circumference (HC), abdomen circumference, and femur length were recorded. Also, the hemodynamic parameters including peak flow velocity (PSV) of MCA, and pulsatility index (PI) and resistance index (RI) of MCA, UmA and UtA were measured. The cerebral placenta ratios (CPR=MCA-PI/UmA-PI; CRR=MCA-RI/UmA-RI) were calculated based on the measurements.

  Results  The MCA-PSV (ranged from 13.63-37.96 cm/s) indicated a mild elevation trend during the gestation; however, the other parameters including RI, PI of MCA, UmA, UtA and CPR, CRR remained stable during this period. The MCA-RI and MCA-PI were significantly correlated with UmA-RI and UmA-PI, respectively (r=0.51, P < 0.01; r=0.65, P < 0.01). However, there was no correlation within the corresponding indexes between UtA and MCA or UmA. The MCA-PSV(cm/s) showed a significantly linear relationship with the gestational age (GA, week):MCA-PSV=-0.17+1.02×GA (r=0.67, P < 0.01). The MCA-PSV was significantly correlated with BPD and HC (r=0.29, P < 0.01; r=0.32, P < 0.01).

  Conclusions  The RI and PI of MCA are closely correlated with those of UmA, but show no such correlation with those of UtA.The PSV in fetal brain is closely associated with the gestational week and affected by brain development.