Overview

• Analyzing 5,142,339 recognized pregnancies in Ontario from 1992 to 2023, the study found 687,692 involved preconception CT exposure.
• Spontaneous pregnancy loss occurred at 101 per 1,000 with no prior CT versus 117 with one scan, 130 with two, and 142 with three or more, corresponding to adjusted increases of 8%, 14%, and 19%.
• Congenital anomalies in live births were 62 per 1,000 without prior CT versus 84, 96, and 105 with one, two, and three or more scans, respectively.
• Risks were slightly higher after abdomen, pelvis, or lower-spine imaging and rose as the most recent scan neared conception, with about half of scans occurring four or more years earlier.
• An accompanying editorial called the implications profound and urged stronger counseling on cumulative radiation, while experts noted probable confounding and encouraged ultrasound or MRI when clinically reasonable.