In developing countries, where 90 percent of the 250 million low-birth-weight babies are born each year, birth weight is closely associated with the health and survival of infants.

The effects of prenatal supplements on birth weight and intrauterine growth have not been well studied, however an overview of five trials showed a 40 percent lower risk of low birth weight when mothers took folic acid supplements during pregnancy.

Unicef promotes the use of multiple supplements for pregnant women in the developing world, believing that they will provide health benefits to the mother and infant. However, there is little data on the effectiveness of such supplementation on pregnancy outcomes.

In order to determine the effects of prenatal supplementation, one study assessed the impact of pregnant women taking daily folic acid, folic acid-iron, folic acid-iron-zinc, or a multiple micronutrient supplement (containing 14 micronutrients including folic acid, iron and zinc), all with vitamin A, compared with vitamin A alone (as control) on birth weight and percentage of low-birth-weight babies.

The study was conducted in rural Nepal, where over 43 percent of babies weigh less than 2,500 grams at birth. After supplementation, the incidence of low birth weight declined 16 percent in the folic acid-iron group and 14 percent in the multiple micronutrient group.

Researchers state that based on these results, 11 women would need to take folic acid-iron supplements and 12 women would need to take multiple micronutrient supplements to avoid having one low-birth-weight baby within the group.

According to the study, low-birth-weight infants have a four to 10 times higher risk of neonatal death, however increases in birth weight may not always result in improved health or survival. Researchers followed the newborns in the study for the first six months of life and found that survival rates were unrelated to birth weight.

Researchers concluded that prenatal folic acid-iron supplements modestly reduce the risk of having a low-birth-weight baby and multiple micronutrient supplements offer no additional benefit over folic acid-iron supplements.

British Medical Journal March 15, 2003;326:571 (Full Text Article)

Dr. Mercola's Comments:

It is quite clear, as this study and many others report, that folic acid is necessary to prevent neural tube defects. However, the question becomes: What is the best way to obtain this supplement? My belief is that it is through appropriate amounts of fresh, raw vegetables that are loaded with folic acid and appropriate for your Metabolic Type. Not only will you obtain the folic acid, but you will also receive the other accessory micronutrients, many of which have yet to be determined or discovered. It is whole, raw, unprocessed food that is required for optimum health and fetuses are no exception. If a pregnant woman believes that she can’t, for whatever reason, consume enough vegetables, then a supplement would be prudent. However, I would caution against the use of prescription based ones. All you really need, as this study suggests, is folic acid. I would obtain this from another supplement rather than prescribed ones. If you are nervous and really feel the need for a prenatal supplement, go to a health food store and purchase one there instead of from a drug company that loads them with plenty of low-quality, synthetic vitamins that are clearly not equivalent to the better, more natural ones. Additionally, you could consider Living Fuel, a nutritional superfood that provides almost all of the necessary nutrients in a convenient powder form. Please understand that whole foods are best, but if you are not obtaining real, healthy foods, then Living Fuel Rx offers concentrated sources of vitamins, minerals, proteins, essential fats, enzymes and more. Related Articles: Should You Take Vitamin Supplements? Kids Taking Unnecessary Supplements