The Korea Food and Drug Administration (KFDA) has asked the Korean Hospital Association and other medical groups to restrict ultrasonic scans solely to diagnostic purposes, saying pregnant women are undergoing the procedure too often.

According to KFDA on Monday, pregnant women in Korea underwent an average of 10.7 ultrasonic scans. That was more than three times the average number in advanced countries, where only one to three ultrasounds are covered by state health insurance, so those procedures rarely exceed three sessions, the KFDA said.

Ultrasounds are generally safe and used to assess the size, position, movements and pulse of a fetus. But a KFDA official said, "We cannot rule out the possibility of ultrasonic waves having physical effects on body tissue or causing temperatures to rise. We need to refrain from using ultrasonic scans for non-diagnostic purposes such as capturing images of fetuses just to keep as souvenirs."