The Effect Of Color Doppler Ultrasound During Different Durations Of Pregnancy On Offspring's' Brain Functions

Objective The safety of diagnostic ultrasound is an arising important topic in medical research. Therefore, the possibility of diagnostic CDUS causing adverse effects on fetal brain functions is an important but little-studied question. Most research focuses on the molecular level or examines the brain's microstructure, while experimental studies on function are almost nonexistent. The intent of this study is to begin to bridge that gap. The objective of this experiment is to study the effect of color Doppler ultrasound (CDUS) during different durations of pregnancy on offspring's brain functions and ultrastructure of hippocampus in rats.Methods Pregnant Sprague-Dawley(SD) rats were randomly divided into four groups according to the exposure time: control group (0 min group), 10 min group , 20 min group and 30 min group, and were exposed to ultrasound (3.0MHz, MI=1.6, Tis=1.8) differently on 6th, 12th, and 18th days of gestation. In each group, neonatal rats were selected to open field test for locomotion activity and then to Morris water maze test for learning and memory abilities at ninety days old. Then morphology of hippocampus was observed by transmission electron microscope.Results In the open field test, to the total distance,average velocity,activity,central distance and central time ,there were no differences between the 10 min group,20min group ,30min and the control group(P>0.05).In the Morris water maze test ,the escape latencies of rats in 30min group(21.96±5.29) were significantly longer than those of the control group(10.78±3.89 )(P <0. 05), the ratio of time spent in the target quadrant in 30min group(27.89%±2.14%) were significantly lower than that of the control group(37.42%±2.37%); and there were no significant differences between the 10 min group (9.98±2.12,37.42%±1.89%),20min (12.23±2.56,34.11%±2.65%)and the control (10.78±3.89, 37.42%±2.37%)group(P>0.05).To the ultrastructure, there were no differences between the exposed group and the control group.Conclusions Color Doppler ultrasound during different durations of pregnancy doesn't have any effect on offspring' locomotion activity. While thirty-min exposures to CDUS in utero during different durations of pregnancy could adversely affect the learning and memorizing ability of the rat offspring, and the 10 min exposures had no demonstrable effect.