The Rothman study's findings on vitamin A intake during pregnancy were not statistically significant for women consuming vitamin A from food alone and had methodological issues.

“he specifically addresses it here in a sidebar in the his article on vitamin a and pregnancy he says the claim that intakes of vitamin a over ten thousand iu can increase the risk of birth defects can be traced back to a 1995 paper published by a group of researchers led by dr kenneth rothman of boston university and he goes on to talk about the results of the study the researchers followed almost 23 000 women over the course of their pregnancies found that women who consumed more than 10 000 iu of vitamin a during the first trimester gave birth offspring with a 2.4 greater fold greater risk of total birth defects and a 4.8 fold greater risk of cranial neural crest defects among 188 women who consumed this amount of vitamin a from quote food alone there was an 80 percent increase in the risk of total birth defects and two times the risk of cranial neural crest defects because there were so few women women consuming vitamin a from quote food alone however the researchers could not conclusively distinguish the association from the effect of chance that means it was not statistically significant”