Failure to demonstrate an effect of in vivo diagnostic ultrasound on sister chromatid exchange frequency in amniotic fluid cells.

Antepartum use of diagnostic ultrasound has markedly reduced radiation exposure of the fetus. Previous investigations have documented the safety of ultrasound, but concern persists regarding its long-term effects. As new methods become available to study possible subtle effects of ultrasound, it is important to reevaluate this technique continually because of its universal use in obstetrics and elsewhere. We report results of in vivo studies of effect of diagnostic ultrasound on the sister chromatid exchange (SCE) frequency in amniotic fluid cells. SCE is a cytogenetic phenomenon believed to be a sensitive indicator of environmental perturbations and chromosome stability. In amniotic fluid cells from six pregnancies without ultrasound exposure and in 34 pregnancies that received varying amount of ultrasound immediately before amniocentesis, there was no difference in SCE frequency in exposed verus nonexposed cells. These data, which appear to confirm again the safety of ultrasound, are reassuring to both patients and clinicians.