[Nuclear-medical irradiation during pregnancy. Risk assessment for the offspring]

AIM To estimate and evaluate the risks for the offspring due to the administration of radiopharmaceuticals to women during the first pregnancy weeks after conception (weeks p.c.).

The in-utero exposition of the embryo due to diagnostic nuclear medicine procedures, for which diagnostic reference levels (DRL) are specified, as well as due to radio iodine therapy (RIT) was determined. To this end, it is assumed that the activity of the diagnostic radiopharmaceuticals administered to the mother corresponds with the DRL and amounts to 600 MBq or 4 GBq 131I for RIT of benign or malignant thyroid disease, respectively. Based on these data, the radiation risk for the offspring was assessed and compared with the spontaneous risks (R0).

The dose for the offspring does not exceed 7.8 mSv for the diagnostic procedures considered, resulting in an excess risk for the offspring of less than 0.12% (R0 approximately 25%) to die from cancer during life, of less than 0.07% (R0 approximately 0.2%) to develop cancer up to the age of 15 years, and of less than 0.16% (R0 approximately 2%) for hereditary effects. RIT during the first 8 weeks p.c. results in doses for the offspring of about 100-460 mSv, resulting in an excess risk for malformations of the child of 3.4%-22% (R0 approximately 6%).

The risk of stochastic radiation effects for the offspring due to a diagnostic nuclear medicine procedure of the mother during the first 8 weeks p.c. is--compared with the spontaneous risks--very small; deterministic effects are unlikely. In contrast, deterministic effects for the offspring may occur following RIT. In order to decide on a possibly indicated abortion after RIT, an individual risk assessment is mandatory.