Mammogram Safety During Pregnancy: Risks & Concerns

Question
Dear Doctor:

I'm 35 years old with no children.  I had a negative pregnancy test on 3/11/08, a positive ovulation test on 3/12/08 (and intercourse that day), and a mammogram on 3/14/08 without shield since I had a negative pregnancy test 3 days earlier.  Today is 3/26/08 and I have a positive pregnancy test and I'm concerned about effects of the mammogram's radiation on the fetus.  How worried should I be?

Answer
Dear Cindy,

There is a fairly common theory amongst health care providers called the "all-or-nothing phenomenon". Essentially this refers to a window of time in the first 2-3 weeks after conception when there is none of the crucial fetal development going on. During this window, if the new fetus is exposed to anything which will prove to be "defective", the strong likelihood is that it will spontaneously abort. However, in most cases, this window allows for great latitude. My personal suspicion is it was a nature-made, divine protection since most women will not know they are pregnant for at least 2-3 weeks after conception has occurred.

In your case, fertilization would have only taken place in the 48 hours prior to the mammogram. The fertilized egg would not even have implanted into the uterine lining yet. Not to mention that with a mammography study, the estimated fetal mrad exposure is usually negligible. I would suspect there is very little to worry about in this situation.

I hope this has helped you and answered your question. I wish you well.

Brenda