National study: obstetric ultrasound more common than previously reported.(News)

PHILADELPHIA -- The utilization of obstetric ultrasound is increasing and now averages 3.5 scans per singleton delivery, according to a national study of claims and encounter data for commercially insured U.S. women.

At least one ultrasound was performed during 89% of these pregnancies, which is an increase from 67% in 2000, Dr. Joanne Armstrong said at the annual meeting of the American College of Obstetricians and Gynecologists.

"This study is the first attempt to describe the use of ultrasound in American women in the private sector. The frequency is a lot higher than what has been previously reported" from publicly available birth certificate data, she said.

"Birth certificate data tend to underreport because a birth certificate only asks if ultrasound occurred and does not ask how many," continued Dr. Armstrong, who is a member of the department of women's health at Aetna Inc., Blue Bell. Pa.

The average of 3.5 scans per pregnancy was a "minimal estimate" because it is only paid scans. "Scans performed but not individually billed and paid, such as scans performed under capitated radiology arrangements, are not captured," she said.

Dr. Armstrong's study used claims and encounter data in a national database of HMO members with a delivery code for a live, singleton birth during 2002 and an effective date of coverage at least 10 months before the delivery was analyzed.

A total of 48,751 singleton deliveries were identified, of which 43,480 (89%) had at least one obstetric ultrasound peformed. A total of 172,942 scans or 3.5 per delivery were performed.