THURSDAY, July 25, 2019 (HealthDay News) -- From 1996 to 2016, the rates of medical imaging among pregnant women increased in the United States and Ontario, Canada, according to a study published online July 24 in JAMA Network Open.
Marilyn L. Kwan, Ph.D., from Kaiser Permanente Northern California in Oakland, and colleagues conducted a retrospective cohort study involving pregnant women from U.S. sites and Ontario, Canada, to examine imaging rates during pregnancy. Data were included from 3,497,603 pregnancies in 2,211,789 women; 26 percent from U.S. sites.
The researchers observed an increase in computed tomography (CT) imaging rates in the United States, from 2.0 examinations/1,000 pregnancies in 1996 to 11.4/1,000 in 2007, then remained stable through 2010, and decreased to 9.3/1,000 pregnancies by 2016; the overall increase was 3.7-fold. In Ontario, Canada, there was a more gradual increase in CT rates, from 2.0/1,000 pregnancies in 1996 to 6.2/1,000 in 2016. Steady increases were seen in magnetic resonance imaging rates, from 1.0/1,000 pregnancies in 1996 to 11.9/1,000 in 2016 in the United States, and from 0.5 to 9.8/1,000 pregnancies in Ontario. Radiography rates doubled from 34.5/1,000 pregnancies in 1996 to 72.6/1,000 pregnancies in 1999, and decreased to 47.6/1,000 pregnancies 2016 in the United States; in Ontario, the rates increased slowly.
"Over the 21-year study period, CT rates increased 3.7-fold in the U.S. sites and 2.0-fold in Ontario, whereas the use of other imaging modalities with ionizing radiation decreased," the authors write.
One author disclosed financial ties to Bayer Healthcare.