Dental X-rays linked to small babies

[Monique]

http://www.newscientist.com/news/news.jsp?id=ns99994927"

Women who have a dental X-ray during pregnancy are three times more likely to give birth to a low birth weight baby than those who do not, suggests a new study.

The results challenge conventional guidelines which suggest that only medical X-rays directly to the reproductive organs are of concern during pregnancy, say the researchers at the University of Washington School of Dentistry, Seattle, US.

"When we first noticed this association, we were very surprised," says Philippe Hujoel, who led the study. "Researchers had assumed that only direct radiation to the uterus or foetus would be harmful, and that radiation to the head and neck region would not have negative effects on pregnancies."

He adds the findings were also surprising in that the amount of radiation women are exposed to during a dental X-ray is "very low and generally thought to be incapable of inducing observable health effects".

It seems that the organs that could be affected are the hypothalamus, the pituitary and the thyroid gland. Although it is ofcourse possible that requiring an X-ray itself might be the riskfactor.. The dental records of total 4500 women were compared.

 

[Vance]

http://www.cheshire-med.com/programs/chi/toothtips/xrays.html

i don't know, i find it good for kids, which is also what the title says, so i post that link...lol...

 

[Monique]

Of course there is a difference between an unborn fetus and a child with teeth, developmentally.

 

[Vance]

Of course there is a difference between an unborn fetus and a child with teeth, developmentally.

(lol)
After I read your article in your link again, I know now that I was wrong about what I posted...sorry, next time, surely there is no such a thing happening again...lol...


<I would like to have a signature but i couldn't make it, where is the option ?>
Thanks,
-Fiona

 

[Moonbear]

I read the JAMA article where this was published and some things struck me as odd. They say the corrected for a number of risk factors associated with low birth weight, but I'm not really sure how that works. There were quite significant differences in the populations of women with low birth weight (either pre-term or term deliveries) and those with normal birth weight. I didn't focus too much on the pre-term group because the comparison between term low and normal birth weight groups seems more straightforward and less likely to have more confounds. The group differences that really stood out were maternal weight-gain during pregnancy (much lower in the low birth weight group) and self-reported smoking during pregnancy. Rather than seeing a statistical game played to try to adjust for these differences, which I'm never convinced is all that reliable, I'd have rather seen a comparison among more similar groups. For example, find the non-smokers that avoided alcohol, had adequate pre-natal care, no gestational diabetes, etc, and compare them between groups of women with low birth weight and normal birth weight infants all born at term, and see if there is a difference in dental x-ray exposure. Otherwise, the alternate interpretation that the factors that predispose one to having a low birth weight infant also predispose one to needing dental care. For example, poor nutrition or excessive vomiting during morning sickness (also contributing to poor nutrition) can lead to dental problems and also low birth weight.

Something interesting in this study (or interesting because of the lack of it in the study) is that while they are focusing on the hypothesis that the x-rays are affecting thyroid function, they didn't include thyroid function in their analysis. Hypothyroidism is a common problem during pregnancy, and thyroid hormone replacement is provided to women diagnosed with this problem.

Another factor that would have been helpful to see included would be how many of these women had sought dental care in the previous year to their pregnancy, regardless of whether they had x-rays taken. This would generally help identify whether those with higher x-ray exposures were getting regular dental care or if they waited until they had a problem before going to the dentist, thus requiring more x-rays to diagnose and treat the problem. This might identify that those with low birth weights may actually be generally not getting as good of routine health/dental care, waiting until there is a problem to get treated.

Another group difference that I'm not sure if was included in the correction for risk was the predominance of single women, and women of lower educational level having low birth weight babies. The stress of lacking a stable support system during pregnancy could also lead to lower birth weights, and stress can also affect dental health.