Introduction: An aim of the first phase of the present authors' prospective clinical trial was to determine the variation of pulsatile index (PI) in the median cerebral artery (MCA) in low- and in high-risk pregnancies with gestational hypertension, diabetes mellitus, intrauterine growth restriction (IUGR), and congenital thrombophilia, after constant sound stimuli. Materials and Methods: Study was organized as multicentric prospective clinical trial under the supervision of Ministry of Health and Education of Republic of Serbia over four years from 2011-2014. The study included 60 patients in low-risk pregnancies, 31 patients with gestational hypertension, 17 patients with diabetes in pregnancy, four with IUGR, and nine patients with congenital thrombophilia. Ultrasound prenatal auditory screening was performed after the 27^th week of gestation, following the protocol established in 1992. Defined sound stimulus was digitally generated sound intensity 90 dB, frequency range 1,500-4,500 Hz, and duration 0.2 seconds. Result: There is significant statistical difference between low-risk pregnancies and pregnancies with gestational hypertension, and insulin dependent diabetes mellitus. Conclusion: A small response interval was detected in pregnancies complicated with diabetes mellitus insulin dependent and gestational hypertension. The authors can conclude that these fetuses are in chronic hypoxia which results in their low reactivity to external stimulation.