The purpose of paper is an estimation of morphometric parameters and status of NO-dependent mechanisms of embryos placenta of white rats in normal conditions, experimental disturbance of the utero-placental circulation and after the nitric oxide donator "Deponit-10" using. The volume density of blood vessels in the placenta and placental vascular exchange area significantly increases under chronic intrauterine hypoxia. The donator of nitric oxide has a positive effect on morphometric parameters of the placenta, provides effective adaptation of feto-placental blood flow to hypoxia and could be useful for clinical practice.