Before revision:  We report the most encompassing set of fetal HRV measures known to-date and identify those HRV measures that are specific to the vagal modulation of HRV and show recovery dynamic due to fetal surgery. Our findings have clinical significance for in utero monitoring of fetal health during surgery.
After revision:  We report the most encompassing set of fetal HRV measures known to-date and identify those HRV measures that are specific to the vagal modulation of fHRV: Multiscale time irreversibility asymmetry index (AsymI), Detrended fluctuation analysis (DFA) alpha1, Kullback-Leibler permutation entropy (KLPE) and Scale dependent Lyapunov exponent slope (SDLE alpha).