Is smoking an indication for prenatal ultrasonography? RADIUS Study Group

To evaluate whether ultrasound screening during pregnancy decreases the frequency of smoking in women who present with a history of smoking.

The Routine Antenatal Diagnostic Imaging with Ultrasound Study was a multicenter, randomized clinical trial of ultrasound screening during pregnancy. We obtained information on smoking habits during pregnancy from birth certificate records for the subset of women who were delivered of a neonate in Missouri hospitals, and determined the effect of ultrasound screening on smoking habits during pregnancy.

The study was conducted in multiple practices in six states.

Women who registered for prenatal care at participating practices.

Women in the screened group were routinely scheduled for ultrasound screening at 16 to 22 weeks' gestation and at 31 to 35 weeks' gestation. Those in the control group received ultrasound screening only for medical indications, as determined by their physicians.

Smoking habits were measured by the number of cigarettes smoked per day.

There was no difference in the rates of smoking cessation between the screened group and the control group. For those who continued smoking, the mean number of cigarettes smoked per day, as reported at the time of delivery, was slightly higher in the screened group.

Ultrasound screening does not reduce the frequency of smoking during pregnancy.