Radiation is mainly of two types – ionizing and non-ionizing radiation. In pregnancy only non - ionizing radiation is used. Effects are very less in pregnancy than what is actually predicted. According to ACOG, exposure to x-rays during pregnancy is not an indication for therapeutic abortion. Fetal sensitivity to radiation depends upon – radiation dose to fetus and post conceptional period. Health effects are grouped into teratogenesis, carcinogenesis and mutagenesis. 

Keywords: Ionizing; Non- Ionizing; Post- Conceptional Period.