Maximum dose of radiation exposure during pregnancy is

The biological effects of x-rays are caused by an electrochemical reaction that can damage tissue. Embryo-fetal risks from low-dose diagnostic radiation appear to be minimal. Current evidence suggests that there are no increased risks for malformations, growth restriction, or aboion from a radiation dose of less than 0.05 Gy (5 rad). Reference: William&;s Obstetrics; 24th edition; Chapter 46; General Considerations and Maternal Evaluation