The finding may indicate that taking vitamin E supplements or eat a diet high in vitamin E may prevent low birth weight.   If that is true, too much of vitamin E in the blood may also push a normal fetus to grow too fast.

But the association may simply indicate that vitamin E is a biomarker and other factors associated with vitamin E such as overall nutrition status of a diet may contribute to the fast growth of the fetus.

For the study, Dr. Theresa O. Scholl and colleagues at the University of Medicine and Dentistry of New Jersey in Stratford followed 1,231 pregnant women for their blood concentrations of two forms of vitamin E at the beginning of the study and during the 28th week of pregnancy.

However, only alpha-tocopherol was related to fetal growth, the researchers found.   Birth weights were highest among women with the highest alpha-tocopherol levels.

Alpha-tocopherol is often present in vitamin E supplement, meaning that those women with highest alpha-tocopherol may take a vitamin supplement such as prenatal vitamins.   Some observation indicated that women taking vitamin supplements tend to deliver babies earlier than those who do not take any. But published studies on the issue are rare.

According to the current study, the women with the highest concentrations of vitamin E were also three times less likely to have a smaller-than-average baby than mothers with the lowest levels of the vitamin.

The results do not provide anything consumers may take home as a dietary guideline as the results do not mean that there is any cause-effect relation between blood vitamin E and fetus growth, a scientist affiliated with foodconsumer.org cautioned.

Even if alpha-tocopherol is indeed promoting growth of the fetus, healthy pregnant women may better consult with her ob/gyn about taking an extra amount of a vitamin E supplement because anything that promotes the fetus growth can be good in some cases, but bad in others, the scientist commented.