Nav: Home

Worrisome increase in some medical scans during pregnancy

July 24, 2019

Use of medical imaging during pregnancy increased significantly in the United States, a new study has found, with nearly a four-fold rise over the last two decades in the number of women undergoing computed tomography (CT) scans, which expose mothers and fetuses to radiation. Pregnant women are warned to minimize radiation exposure.

This is the first large, multi-center study to assess the amount of advanced imaging occurring during pregnancy. The study, which included authors from UC San Francisco, UC Davis and Kaiser Permanente, published July 24, 2019, in JAMA Network Open.

Over the 21-year study period, rates of CT increased nearly four-fold in the United States, and doubled in Ontario, Canada.

"Most pregnant women get routine ultrasound to monitor fetal growth, which delivers no ionizing radiation," said co-lead author Diana L. Miglioretti, PhD, biostatistics professor at the UC Davis Department of Public Health Sciences and senior investigator with Kaiser Permanente Washington Health Research. "But occasionally, doctors may want to use advanced imaging to detect or rule out a serious medical condition of the expectant mother, most often pulmonary embolism, brain trauma or aneurysm, or appendicitis."

That imaging could include CT, which involves a large dose of ionizing radiation -- many times more than a chest X-ray. Ionizing radiation carries potential health risks to the developing fetus, including congenital abnormalities, developmental delays, or cancer.

"Imaging can be helpful, but it can be overused," said senior author Rebecca Smith-Bindman, MD, a UCSF professor of radiology, epidemiology and biostatistics, and of obstetrics, gynecology and reproductive medicine. "Always, but especially if you're pregnant, you should ask whether it is really medically necessary to have any imaging test that involves ionizing radiation."

The researchers said alternative methods that do not use radiation should be considered whenever possible to avoid unnecessary exposure of women and fetuses to imaging radiation.

"There's a tradeoff," Smith-Bindman said. "CT scans provide the clearest images, they can be done quickly, and are less expensive and more widely available. However, CT scans have the most ionizing radiation and they are commonly done in places of the body where the fetus is exposed to the radiation."

The authors said that professional organizations have not consistently recommended minimizing medical imaging during pregnancy. Their research opens a new avenue of inquiry into the potential risks involved.

"This study has given us a chance to look more closely at the use of advanced imaging in pregnancy," said Marilyn L. Kwan, co-lead author and senior research scientist in the Kaiser Permanente Northern California Division of Research. "It's important to quantify exposure to ionizing radiation because it can cause cancer and birth defects, and should be kept to a minimum, especially during pregnancy."

For their study, which tracked the combined use of advanced medical imaging during pregnancy, the researchers analyzed more than 3.5 million pregnancies at six U.S. health systems and the provincial health system of Ontario, Canada, between January 1, 1996, and December 31, 2016. They reviewed the use of advanced imaging, including CT, magnetic resonance imaging (MRI), conventional radiography, angiography and nuclear medicine.

During the 21-year study, 5.3 percent of pregnant women at U.S. sites and 3.6 percent in Ontario underwent imaging with ionizing radiation, the authors said. Rates of CT scanning during pregnancy in the U.S. started leveling off in 2007 and have been trending downward since 2010, the study found. Meanwhile, overall rates continued to climb in Ontario, but in 2016, they were nonetheless 33 percent lower than in the U.S. They also found that Ontario utilized MRI, which doesn't use radiation, more often than CT, which does.

Altogether, nearly one in 100 pregnancies in the United States and approximately two-thirds in Canada involved CT in 2016, researchers found. Imaging rates during the course of the study were highest in women under 20 and over 40 years old, as well as those who delivered preterm or were black, Native American or Hispanic.
-end-
Authors: Other authors include Prachi Chavan, MPH, of the Radiology Outcomes Research Lab at UCSF; and Emily C. Marlow, MPH, of UC Davis. Please see the paper for the full list.

Funding: The study was supported by the National Cancer Institute at the National Institutes of Health (R01CA185687 and R50CA211115). The Ontario, Canada portion of the study was also supported by ICES, which is funded by an annual grant from the Ontario Ministry of Health, Long-Term Care. The researchers declare no conflicts of interest.

About UCSF: The University of California, San Francisco (UCSF) is exclusively focused on the health sciences and is dedicated to promoting health worldwide through advanced biomedical research, graduate-level education in the life sciences and health professions, and excellence in patient care. It includes UCSF Health, which includes top-ranked pediatric and adult hospitals, as well as affiliations throughout the Bay Area. Learn more at https://www.ucsf.edu, or see our Fact Sheet.

About UC Davis Health: UC Davis Health is improving lives and transforming health care by providing excellent patient care, conducting groundbreaking research, fostering innovative, interprofessional education, and creating dynamic, productive partnerships with the community. For more information, visit http://www.health.ucdavis.edu.

University of California - San Francisco

Related Pregnancy Articles:

Are women using e-cigarettes during preconception and/or pregnancy?
A new study of 1,365 racially/ethnically diverse, low-income pregnant women found that 4% reported e-cigarette use.
A better pregnancy test for whales
To determine whale pregnancy, researchers have relied on visual cues or hormone tests of blubber collected via darts, but the results were often inconclusive.
Cannabis use during pregnancy
The large health care system Kaiser Permanente Northern California provides universal screening for prenatal cannabis use in women during pregnancy by self-report and urine toxicology testing.
Questions and answers about cannabis use during pregnancy
A new study shows that women have many medical questions about the use of cannabis both before and during pregnancy, and during the postpartum period while breastfeeding.
The effect of taking antidepressants during pregnancy
Exposure to antidepressants during pregnancy and the first weeks of life can alter sensory processing well into adulthood, according to research in mice recently published in eNeuro.
Is ivermectin safe during pregnancy?
Is it safe to give ivermectin to pregnant women? To answer this question, researchers from the Barcelona Institute for Global Health (ISGlobal), an institution supported by 'la Caixa,' conducted a systematic review and meta-analysis of studies that reported cases of accidental exposure to the drug among pregnant women.
Going to sleep on your back in late pregnancy
This study looked at whether going to sleep on your back in the third trimester of pregnancy was associated with average lower birth weights.
Opioid use disorder in pregnancy: 5 things to know
Opioid use is increasing in pregnancy as well as the general population.
Medical imaging rates during pregnancy
Researchers looked at rates of medical imaging (CT, MRI, conventional x-rays, angiography, fluoroscopy and nuclear medicine) during pregnancy in this observational study that included nearly 3.5 million pregnant women in the United States and Canada from 1996 to 2016.
New research on diet and supplements during pregnancy and beyond
The foods and nutrients a woman consumes while pregnant have important health implications for her and her baby.
More Pregnancy News and Pregnancy Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Teaching For Better Humans 2.0
More than test scores or good grades–what do kids need for the future? This hour, TED speakers explore how to help children grow into better humans, both during and after this time of crisis. Guests include educators Richard Culatta and Liz Kleinrock, psychologist Thomas Curran, and writer Jacqueline Woodson.
Now Playing: Science for the People

#556 The Power of Friendship
It's 2020 and times are tough. Maybe some of us are learning about social distancing the hard way. Maybe we just are all a little anxious. No matter what, we could probably use a friend. But what is a friend, exactly? And why do we need them so much? This week host Bethany Brookshire speaks with Lydia Denworth, author of the new book "Friendship: The Evolution, Biology, and Extraordinary Power of Life's Fundamental Bond". This episode is hosted by Bethany Brookshire, science writer from Science News.
Now Playing: Radiolab

Space
One of the most consistent questions we get at the show is from parents who want to know which episodes are kid-friendly and which aren't. So today, we're releasing a separate feed, Radiolab for Kids. To kick it off, we're rerunning an all-time favorite episode: Space. In the 60's, space exploration was an American obsession. This hour, we chart the path from romance to increasing cynicism. We begin with Ann Druyan, widow of Carl Sagan, with a story about the Voyager expedition, true love, and a golden record that travels through space. And astrophysicist Neil de Grasse Tyson explains the Coepernican Principle, and just how insignificant we are. Support Radiolab today at Radiolab.org/donate.