Vitamin deficiency could harm your unborn baby

Vitamin B12 deficiency linked to spina bifida

Before becoming pregnant, women need to get enough vitamin B12 in addition to folate to cut their risk of having a baby with a serious birth defect of the brain and spinal cord, researchers say, after a study in which women with the lowest vitamin B12 levels were five times more likely to have a baby with a neural tube defect than those with the highest levels.

Neural tube defects can lead to lifelong disability or death. The two most common examples are spina bifida, in which the spinal cord and the bones of the back don’t form properly, and anencephaly, a fatal condition in which the brain and skull bones don’t develop normally. These problems are typically picked up during ultrasound scans carried out during the second trimester (weeks 13-28).

Dr James Mills, of the US National Institutes of Health, one of the researchers, says the study showed that vitamin B12 deficiency was a risk factor for neural tube defects independent of folate, another B vitamin. Many women now know of the importance of folate and many foods are fortified with it, with the result that there has been a drop in the incidence of neural tube defects. Current advice also recommends that pregnant women boost their folate levels by taking a supplement of folic acid (the synthetic form of folate) during their pregnancy. As a precaution, if you’re planning to start trying for a baby, start taking folic acid beforehand.

Vitamin B12 is essential to maintain healthy nerve cells and red blood cells. It’s found in meat, dairy products, eggs, fish, shellfish and fortified breakfast cereals. It also can be taken as an individual supplement or in a multivitamin. The defects associated with a vitamin B12 deficiency can occur within the first four weeks of pregnancy, so women who are vegetarian or vegan need to keep a particularly close eye on their B12 intake. This also applies to women with gastro-intestinal disorders such as inflammatory bowel disease, which may prevent them from absorbing sufficient amounts of B12.

The study is published in the March 2009 issue of Pediatrics.

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