The recommended monthly limit to the fetus is
The NCRP recommends a monthly limit of 0.5 mSv (50 mrem) to the embryo or fetus once a woman declares her pregnancy. In contrast to this, the ICRP recommends a limit of 2 mSv (200 mrem) to the surface of the woman&;s abdomen (lower trunk) for the remainder of the pregnancy. These recommendations are essentially similar and are designed to limit the risk of mental retardation, other congenital malformations, and carcinogenesisReference: Eric J Hall Textbook of Radiobiology for Radiologist; 5th edition
0.05 mSv
0.1 mSv
0.5 mSv
2 mSv
Radiotherapy