CT scan in pregnancy

[Denzil]

Does anyone know the risks of CT in pregnancy? I can understand a carcinogenic risk to the foetus, but can a single pelvic/abdo CT in early pregnancy cause a miscarriage (putting aside the mother having some sort of reaction to any contrast given)?

If the CT scan was a chest CT instead would there be any risk to the foetus?

Just wondering and thanks for any help.

[NorthernLight]

I know nothing official, but my understanding is that most medics would be VERY unhappy exposing a foetus to X-rays, and a CT scan involves much more radiation than an X-Ray so I'd guess, except in a life or death situation, CT would be contraindicated in pregnancy. Don't know about it stimulating miscarriage, but it would certainly be carcinogenic.....
Anyone feel free to correct me if I'm wrong!

[James]

It is all about balancing the risks. There is no doubt that CT scans give significantly more radiation than plain X-rays. The foetus is also much more suseptable in the first trimester of pregnancy. But, if the mother dies from something you missed by not doing a CT then the foetus dies anyway. I have ordered a few CTs on pregnant women in my career, but always for life threatening conditions and after extensive consultation with the patient and the radiologists.

[Denzil]

Thanks both and I'd agree with all of that.

I heard a story from someone of an early miscarriage following a CT and the CT being blamed by the parents. It got me wondering about whether that was likely given how many pregnancies terminate naturally at an early stage.

[James]

There would need to be massive radiation damage to the foetus or placenta to cause a miscarriage. Much, much more than you would get from a CT.

[rjm]

One in four pregnancies miscarry, usually because of foetal anomaly/genetic problems (ie, they miscarry because they are not compatible with life), rarely it is because of an inherent maternal problem such as an autoimmune conditions or clotting problems. As far as I know, a CT scan cannot cause miscarriage. It would however be a risk to the foetus due to the radiation exposure in that it could cause congenital defects. As James says, its a balance of risks.
People usually try to find something to blame for the miscarriage, unfortunately it is a common and usually unpreventable event. Women need reassurance that it wasnt anything they did or could have done to stop it and that in most cases they will have a successful future pregnancy.