Background: While controversy continues about the appropriateness of routine ultrasound screening, there are little data on actual clinical practices or trends in the United States.
Objectives: To examine changes in prenatal ultrasound utilization over time and determine whether ultrasound utilization is associated with maternal age, race/ethnicity, payer status, region of the country, or pregnancy risk group.
Research design: Data on prenatal visits to office-based physicians and hospital outpatient departments from the National Ambulatory Medical Care Survey and the National Hospital Ambulatory Medical Care Survey in 1995 to 2000, 2005, and 2006.
Measure: Prenatal ultrasound use as recorded by a checkbox on the National Ambulatory Medical Care Survey and National Hospital Ambulatory Medical Care Survey survey forms. We calculated the percent of visits with ultrasound, average number of ultrasounds per pregnancy, and adjusted odds ratios (ORs) of receiving an ultrasound.
Results: Overall, the estimated average number of ultrasounds per pregnancy increased from 1.5 in 1995-1997 to 2.7 in 2005-2006. For low-risk pregnancies, the estimated number of ultrasounds during that time period increased from 1.3 to 2.1. For high-risk pregnancies, the number increased from 2.2 to 4.2. In an adjusted analysis, the odds of a woman receiving an ultrasound in 2005-2006 were twice those of a visit in 1995-1997 [OR = 2.02; 95% CI (1.36, 3.00); P < 0.01]. High-risk women had odds of receiving an ultrasound that were almost twice that of women in the low-risk group [OR = 1.91; 95% CI (1.41, 2.59); P < 0.01].
Conclusions: Both low-risk and high-risk pregnant women in the United States are much more likely to receive repeated ultrasound examinations today than they were 10 years ago.