Answer to Question #11765 Submitted to "Ask the Experts"

Category: Pregnancy and Radiation

The following question was answered by an expert in the appropriate field:


I work in a hospital, and I am pregnant now. I would like to ask you if ultraviolet C (UVC) rays could harm my baby? I was in a room where a UVC lamp was running, but I was in the room for only a few seconds.


The brief answer is that UVC rays will not harm your baby. To explain why requires a bit more detail and discussion.

UV radiation is a form of energy, just like visible light is a form of radiation. Like visible light, the largest source of UV radiation is the sun. The sun produces three types of UV radiation that are called UVA, UVB, and UVC. The difference between these three types of UV radiation is their energies and whether that energy can be absorbed by either skin or other materials.

UVC radiation can be produced also by certain types of lightbulbs called germicidal bulbs. These bulbs are considered antibacterial, antiviral, and antimold/antifungal. Germicidal bulbs are used to sterilize air or surfaces. The bulbs are most effective if the surfaces are close to the bulbs or if the surface is exposed to the UVC radiation for very long times. UVC radiation does not have sufficient energy to penetrate surfaces. In fact, UVC radiation does not have sufficient energy to penetrate the outermost (dead) layer of our skin (

Because the UVC radiation does not penetrate the skin, there will be no harm to you or your baby regardless of the time you were exposed to the UVC light. As a public health message, other types of UV radiation (UVA and UVB) are considered hazardous and one should minimize the amount of time of exposure. According to the World Health Organization (WHO), UVA radiation is associated with skin cancers (

So to summarize, UVC rays or radiation is produced by the sun and by special types of lightbulbs. The UVC radiation from lightbulbs is used to sterilize surfaces and air, but it cannot penetrate the dead layer of skin that lines the surface of your body. Since the radiation cannot penetrate your body, there is no effect of the UVC light on your unborn baby.

Paul Charp, PhD

Ask the Experts is posting answers using only SI (the International System of Units) in accordance with international practice. To convert these to traditional units we have prepared a conversion table. You can also view a diagram to help put the radiation information presented in this question and answer in perspective. Explanations of radiation terms can be found here.
Answer posted on 18 October 2016. The information posted on this web page is intended as general reference information only. Specific facts and circumstances may affect the applicability of concepts, materials, and information described herein. The information provided is not a substitute for professional advice and should not be relied upon in the absence of such professional advice. To the best of our knowledge, answers are correct at the time they are posted. Be advised that over time, requirements could change, new data could be made available, and Internet links could change, affecting the correctness of the answers. Answers are the professional opinions of the expert responding to each question; they do not necessarily represent the position of the Health Physics Society.