CT Scans May Pose Risks Prior to Pregnancy, Study Finds

A recent study published in the Annals of Internal Medicine indicates that CT scans conducted before conception could potentially increase the risk of pregnancy loss and congenital anomalies. The comprehensive research analyzed data from over five million pregnancies spanning from 1992 to 2023.

The researchers evaluated nearly 690,000 CT examinations performed within four weeks prior to the estimated time of fertilization. Among confirmed pregnancies, 10.4% ended prematurely due to miscarriage, ectopic pregnancy, or stillbirth. In women who had not undergone CT scans, the rate of pregnancy loss was 101 per 1,000 women. However, this rate increased to 117 per 1,000 for those who had one CT scan, 130 per 1,000 for two scans, and 142 per 1,000 for three or more scans.

The study found that the risk of pregnancy loss was particularly elevated when CT scans focused on the abdomen, pelvis, and lower spine, areas where the developing fetus could be adversely impacted by radiation exposure. The proximity of the scan to the estimated date of conception also correlated with a heightened risk of spontaneous abortion.

In addition to pregnancy loss, the incidence of congenital malformations appeared to be elevated following exposure to X-ray radiation. Among women who did not undergo CT scans in the four weeks preceding conception, the rate of congenital defects was 62 per 1,000 live births. This figure rose to 105 per 1,000 births for those who had multiple CT scans.

The authors of the study, led by researchers from the universities of Montreal and Toronto, highlighted that while the exact mechanisms remain unclear, there is an observable association between pre-conception CT scans and increased risks of both pregnancy loss and congenital anomalies. They recommend seeking alternative imaging methods whenever feasible.

Experts warn that ionizing radiation from CT scans can damage cells, potentially leading to mutations linked to cancer. Daniel Wollschläger, a radiation expert at the University Medical Center Mainz, noted that ionizing radiation can harm the eggs present in a woman's ovaries, raising concerns about the long-term implications for offspring.

While the study's extensive dataset and detailed statistical analyses are commendable, some researchers, including Peter Scholz-Kreisel from the Federal Office for Radiation Protection, pointed out that the study did not adequately evaluate the medical reasons for the CT scans. This lack of information makes it challenging to draw definitive causal relationships between CT exposure and adverse pregnancy outcomes.

In Germany, the frequency of CT examinations has seen a significant uptick since 2007, with a 40% rise in outpatient settings and a doubling in inpatient cases. Josefin Ammon, chairwoman of the Radiological Imaging Procedures section of the German Society for Medical Physics, emphasized that while technological advancements have improved image quality and reduced radiation doses, proper justification for CT scans remains crucial.

For certain clinical questions, alternative imaging methods such as ultrasound can be employed, though their effectiveness often depends on the operator's expertise. Magnetic resonance imaging (MRI) is another option that avoids ionizing radiation altogether.