Repeated ultrasound examinations during pregnancy have no long-term effect on the growth or mental function of the child, new research finds.

A 10-year look at more than 2,700 children, who were examined at 2, 3, 5 and 8 years of age, found “no significant differences indicating deleterious effects of multiple ultrasound studies at any age as measured by standard tests of childhood speech, language, behavior and neurological development,” the scientists stated.

The study, by researchers at the University of Western Australia, appears in the Dec. 4 issue of The Lancet.

The review compared pregnancies in which a single ultrasound exam was done to those in which five exams were conducted. An earlier report, issued in 1993, found a slight decrease in growth among children who had the repeated examinations. The new report said that while there might be a “small effect on fetal growth” associated with multiple examinations, the difference vanished as the children grew up.

The Australian report was published just two days after the American College of Obstetrics and Gynecology (ACOG) issued comprehensive guidelines for the use of ultrasound during pregnancy.

“Ultrasound is safe for the fetus when used appropriately,” the guidelines said. But “casual use of ultrasonography, especially during pregnancy, should be avoided,” ACOG recommended.

The Australian report “makes us comfortable about what we have been doing,” said Dr. Ellen R. Kruger, an obstetrician-gynecologist at the Ochsner Clinic Foundation in New Orleans.

Kruger said she does a single ultrasound examination during virtually every pregnancy, to verify the gestational age of the fetus, estimate the due date, and screen for birth defects. Further exams are done only when possible abnormalities are detected, she said.

“Most obstetricians agree with the American College’s statement that ultrasound examinations should be done only when they are medically necessary, not when they are performed for social reasons,” Kruger said.

Dr. John W. Larsen is an ACOG spokesman, and chairman of obstetrics and gynecology at George Washington University. He expressed concern about businesses that do ultrasound scans to provide parents or grandparents with images for entertainment, rather than for medical purposes.

“Even if the level of harm is very, very small, if it is done for recreation, is that acceptable?” Larsen said.

For medical purposes, the ACOG guidelines state, “the lowest possible ultrasonic setting should be used to get the necessary diagnostic information,” because “ultrasound energy delivered to the fetus cannot be assumed to be completely innocuous.”

The U. S. Food and Drug Administration “views the promotion, sale or lease of ultrasound equipment for making ‘keepsake’ fetal videos as an unapproved use of a medical device,” ACOG noted.

A first ultrasound examination should be done at 16 to 20 weeks for most pregnancies, the guidelines state. A first-trimester exam can be done for pregnancies resulting from “assisted reproductive technologies” or when there are indications of possible problems, such as significant abdominal pain, bleeding or a previous ectopic pregnancy, ACOG said.