Medical Imaging, Radiation, and Fertility

The question of whether medical imaging is safe while trying to conceive generates more anxiety than the doses involved warrant. Part of the problem is that "radiation" triggers a fear response not calibrated to dose. A dental X-ray and a nuclear accident are both described as radiation exposure, but the dose difference is roughly a millionfold.

Ionizing vs Non-Ionizing Radiation

This article covers ionizing radiation from medical imaging (X-rays, CT scans, fluoroscopy). This is fundamentally different from non-ionizing radiation from phones, Wi-Fi, and microwaves. Ionizing radiation has enough energy to damage DNA directly. Non-ionizing radiation does not.

Ultrasound and MRI do not use ionizing radiation at all. Both are considered safe at any point during TTC or pregnancy.

Radiation Doses in Context

Effects on Reproductive Cells at Diagnostic Levels

Oocytes are among the most radiation-sensitive cells in the body, but this sensitivity is relevant at therapeutic doses (multiple grays), not diagnostic doses (fractions of a milligray). Diagnostic imaging doses to the ovaries from dental X-rays are essentially zero. From an HSG, roughly 1 to 5 milligray. From abdominal CT, roughly 10 to 25 milligray. All are far below the threshold at which measurable effects have been observed.

For men, temporary sperm count reductions have been documented after exposures above 150 milligray to the testes. Diagnostic imaging doses are well below this threshold.

For early pregnancy, ACOG states that exposure below 50 milligray has not been associated with fetal anomalies or pregnancy loss. No single diagnostic procedure delivers this dose.

The HSG: Fertility-Specific Imaging

Hysterosalpingography uses fluoroscopy to visualize the uterine cavity and fallopian tubes after contrast injection. The effective dose is typically 1 to 2 mSv, well within safe diagnostic range. It is scheduled during the follicular phase for diagnostic and precautionary reasons.

Interestingly, there is a documented modest increase in conception rates following HSG, possibly because the flushing action clears debris from the tubes.

Occupational Exposure

Healthcare workers in radiation environments should review dosimetry records with their radiation safety officer when planning pregnancy. Annual limits are 50 mSv effective dose, with a 5 mSv embryo/fetus limit once pregnancy is declared. If exposure is within limits, which it almost always is with proper shielding, there is no established fertility risk.

Practical Guidance

• Do not defer necessary diagnostic imaging because of TTC. Dental exams, chest X-rays, mammograms, and HSG are all safe.
• If you know or suspect pregnancy, inform the imaging team before the procedure for appropriate shielding and technique adjustment.
• For non-urgent pelvic imaging, scheduling during the first 10 days of the cycle reduces inadvertent early-pregnancy exposure.
• Ultrasound and MRI involve no ionizing radiation and need no precautions at any point.