The effect of ultrasound exposure in utero on the development of the fetal mouse testis: Adult consequences

The effects of exposure in utero to 1 MHz, continuous-wave ultrasound on adult growth and testicular development in the mouse was investigated. The spatial peak temporal average intensity (I_spta) employed ranged from 1 to 10 W/cm², with exposure durations (t) of 200 s to 20 s. Exposures were made on days 9, 12 or 15 of gestation. Results showed an increase in postpartum deaths, an increase in the number of stillbirths, and a decrease in litter size when I²t ≥ 1125 W² s/cm⁴, such that there was significant loss of pups. Birthweights of pups from nearly all dosage groups was significantly lower than that of the sham or cage control groups. Results also showed that males exposed to ultrasound in utero had decreased testis size and decreased daily sperm production ranging from 9% to 30%. This study showed that ultrasound exposure in utero is capable of disrupting fetal development and having potential subsequent effects on fertility in the adult male.