2018 Volume 5 Issue 1 Pages 74-79
INTRODUCTION：Many studies have shown that human organs are a deterministic chaos. However, it remains unclear whether this is true for the human fetus and mother. We aimed to clarify whether the fetus and mother are a deterministic chaos or not. METHODS：We measured heart sounds of four human fetuses and their mothers during 11th-36th week of gestation using an ultrasonic Doppler apparatus. We investigated non-linearity of the data using the surrogate method. Data modified by three surrogate methods：Random shuffle, Fourier shuffle and Period-shuffle, were used in the study. We conducted a chaotic analysis to recognize the largest Lyapunov exponents（λ1）and the attractor. RESULTS：The result of calculation of correlation dimension is five. λ1 of the original data was significantly different from that of each surrogate data. Fetuses and mothers showed positive λ1 from 11th to 36th week of gestation. Moreover, the attracters were clearly recognized for fetuses and mothers. The results indicate these data deterministic chaos with nonlinear dynamics. DISCUSSION：These results indicate that fetus and mother are a deterministic chaos, and that fetus and mother showed the self-organization ability to interact nonlinearly.