“…This is the primary risk to developing embryos and babies [ [60] , [61] , [62] , [63] ]. Animal research using both non-ultrasound and ultrasound technologies has shown that maternal heat exposure is hazardous to the developing embryo/fetus [ 60 , [64] , [65] , [66] , [67] , [68] , [69] , [70] ]. It seems to be the case if the temperature increases by more than 1.5 °C over the physiological threshold.…”