Ultrasound imaging has been accepted as a safe technique and has been proven useful in the assessment of gestational stage and the diagnosis of many foetal abnormalities. However, prenatal diagnostic ultrasound examination has been quoted as thermally-induced teratogenesis. This in-vivo experimental study investigated the physical and hormonal effects of prenatal ultrasound exposure on rabbit foetuses after an insonation given at different gestational stages for different lengths of exposure time. Analyses of this study showed increase in BMD value and decrease in PTH level were possibly mediated by biological interruption due to the given ultrasound exposure. The study has revealed some detectable physical and hormonal effects of ultrasound exposure on foetal physiological development resulted from insonation given during pregnancy. The outcomes provide new scientific information on the effects of ultrasound exposure on foetus which could trigger possible adverse as well as beneficial effect after birth.