New Research Examines Radiation Risks with CT Exposure Prior to Pregnancy

Exposure to a single computed tomography (CT) scan up to four weeks prior to conception was associated with an eight percent higher risk of spontaneous pregnancy loss and a six percent higher risk of congenital anomaly, according to new research published in the Annals of Internal Medicine.

For the retrospective study, researchers examined the impact of CT-associated radiation with data from 5,142,339 pregnancies and 3,451,968 live births that occurred between 1992 and 2023. The mean maternal age of the cohort was 29, according to the study authors.

Based on adjusted hazard ratios (aHRs), the study authors noted an eight percent higher risk for spontaneous pregnancy loss (including miscarriage, ectopic pregnancy or stillbirth) for one CT scan obtained four weeks prior to pregnancy, a 14 percent higher risk with two CT scans and a 19 percent higher risk for three or more CT scans.

“We found that not only was there a relationship between the use of CT scan and spontaneous pregnancy loss, it was a dose-dependent relationship,” noted lead study author Camille Simard, MD, MSc in a recent interview with Diagnostic Imaging. “We saw that in individuals who had no CT versus one two or three or more CTs, the risk of spontaneous pregnancy loss, or rather, pregnancy loss, increased.”

Exposure to CT scans within four weeks prior to conception was also associated with increased risks of congenital anomalies, according to Dr. Simard, an assistant professor of medicine in the Department of Medicine within the Division of General Internal Medicine at McGill University in Montreal. Utilizing aHRs, Dr. Simard and her colleagues noted a six percent higher risk with one CT scan, an 11 percent higher risk for two CT scans and 15 percent higher risk for three or more CT scans.

Dr. Simard noted that these results were drawn from a retrospective database study with possible residual bias and that the overall effect of CT radiation was small in proportion to the study cohort.

“We have to be cautious with our interpretation. (These are) very interesting findings that hopefully will generate more questioning and more research around this area,” added Dr. Simard. “ … In no way is this study discouraging the use of CT when indicated to rule out important pathologies but I think it generates a hypothesis that maybe other modalities could be explored in this patient population.”

(Editor’s note: For related content, see “New Study Examines Impact of Mammography in Detecting Pregnancy-Associated Breast Cancer,” “FDA Clears AI-Enhanced Portfolio of Ultrasound Systems for Women with High-Risk Pregnancies” and “Predicting Nipple-Areolar Complex Involvement in Early-Stage Breast Cancer: Can Cone-Beam CT Have an Impact?”)

For more insights from Dr. Simard, watch the video below.