You'll find hundreds of files on cleft lip, cleft palate here on

This one is about: Erroneous Study Regarding Environmental Factors

(c) 1996 Wide Smiles
This Document is from WideSmiles Website -
Reprint in whole or in part, with out written permission from Wide Smiles
is prohibited. Email:

A study was mentioned in USA TODAY article regarding environmental factors and their effects. It turns out that the study was inaccurate (and is referenced below) but here are some additional comments on environmental influences on the causes of clefting as well as factors needed to consider in valid studies. The USA Today article is at the end.

Joanne Green of Wide Smiles verifies and says:

I checked the source and the resource to look into this article by USA Today (that's why so many arrows on the quote). Just as I had suspected, this was not a well controlled study, (did not do anything to rule out extraneous factors) and is not widely accepted as an empirically sound study by the medical community. They did not look at such things as the kinds of moves made and why (for instance, if someone lived next to a toxic dump, vs. in the pristine rural community) And they looked at birth defects in general and none in specific.

Also, and this is VERY IMPORTANT, there is a lot more about "environmental factors" than simply where you live - and those factors were not controlled.

For instance, were smoking mothers still smoking? Were epileptic mothers still taking Dilantin? Were alcohol, drug abuse, prenatal drugs, etc, all taken into account? The answer is, no, they were not. And so this study demonstrates only one thing: that you can get statistics to tell you almost anything. In order to be a valid study, the work must be controlled, statistically significant and replicable, and be able to withstand a peer review. This study had only one of those four criteria - and it is the most questionable one. It showed statistical significance. (Or rather, according to it's own hypothesis, an insignificance where it questioned the significance.)

The medical community was not moved by this study. And the medical community, while cautious, is progressive and will embrace findings of empirical significance. That they did not embrace this one tells you something. I think the only place this study will make any splash at all will be USA Today.


In a message dated 96-03-19, you write:

>USA TODAY - article undated  -- located at the above URL
>Study disputes link between environment, cleft palate
>A new study contradicts research that found environmental factors 
>influence the development of cleft palates, a common birth defect. In 
>a study published in 1994, researchers followed women who had produced 
>a baby with any of 24 different birth defects and found that their 
>risk of having a second child with the same defect was cut in half 
>if they moved to a new town. The authors of the new study looked at 
>4,189 women who had a baby with a cleft palate between 1952 and 1987 
>and found that 3% of those who moved had another child with a cleft 
>palate, the same percentage as those who stayed in the same town. 
>The new study, conducted at the Steno Institute of Public Health 
>in Aarhus, Denmark, appears in the New England Journal of Medicine. 
>that's the exact quote...don't bother looking for more info, its not 
>there. Guess you've got to go the source (New England Journal of 

Wide Smiles depends on donations to continue to provide this resource for you.
Please help keep us online!

Cleft Links | Wide Smiles | Photo Gallery