Ultrasound emerging as safer Rh disease test

Ultrasound technology is a safer and more accurate way to diagnose Rh disease than the standard technique of sampling fluid from a fetus to check for the blood problem, researchers report.

The disease, which can lead to stillbirth or brain damage, is caused by blood incompatibility between mother and fetus, and once led to thousands of stillbirths and infant deaths each year in the United States.

The new study, the first to compare the two methods, is important because ultrasound carries little risk, while each sampling of the amniotic fluid, called amniocentesis, poses a small potential for sparking a miscarriage.

Many medical centers, based on small studies, had already begun favoring ultrasound, which is used to assess the speed of blood flowing through a large artery in the brain.

The new study, reported in the July 13 issue of the New England Journal of Medicine, confirmed that such a strategy was justified, said a team led by Dick Oepkes of the Leiden University Medical Center in the Netherlands.