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Peak time interval derived from the three Gaussian waves of the radial pulses measured at the three trimesters of healthy pregnant women. Their means ± SDs are given. (a) Changes of peak time interval between first and second Gaussian waves at the three trimesters; (b) Changes of peak time interval between first and third Gaussian waves at the three trimesters. ∗ represents p < 0.05, and ∗∗ represents p < 0.01.
