Some regularity on how to locate electrodes for higher fECG SNRs*
Zhang Jie-Mina), Huang Xiao-Lina), Guan Qunb), Liu Tie-Bingb)†, Li Pingb), Zhao Yinga), Liu Hong-Xinga)‡
       
Direction relationship between five channels with higher fetal SNR and the fetal cardiac electrical axis in the cases of fetus (a) facing forward and (b) facing backward. The dashed line arrow represents the direction of the fetal cardiac electrical axis and the solid line arrows represent the directions of the five channels.