By Margarita Nahapetyan
Women who do not have adequate levels of vitamin B 12 in their blood before and after getting pregnant, are at a significantly increased risk of giving birth to a child with brain or spinal cord defects, a new study by Irish researchers claims. Babies whose mothers have low levels of the vitamin in addition to folic acid, are nearly 5 times more likely to be born with neural tube defects.
Neural tube defects can lead to lifelong disability, and even cause a lethal outcome. The two most common defects are spina bifida, in which case the spinal cord and back bones do not form in a proper way, and may lead to paralysis, and anencephaly, a fatal condition in which case the brain and bones of the skull do not normally develop.
Most at risk are the vegetarian women, as it is known that vitamin B12 most commonly exists in meat and animal-based foods, the researchers noted. According to Duane Alexander, director of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, vitamin B12 plays a major role in the production of red blood cells and also it is important for an appropriate functioning of the nervous system. These women should undergo medical examination and get a blood test done before getting pregnant in order to realize if they lack vitamin B-12, which is typically included in prenatal vitamins, he said.
The researchers analyzed blood samples that have been collected from Irish women at an early stage of pregnancy, between 1983 and 1990. At that time it was not common for pregnant moms-to-be to take vitamin supplements, and Ireland was considered a country that had very high rates of neural tube defects. All the women have been assigned to 3 groups: women who have previously delivered a child with a neural tube defect, but whose pregnancy was not affected at a current time; women who were known to carry a baby with congenital defects at the time of taking a blood test; and women who were carrying a child with a neural tube defect at the time of getting their blood test done, but who participated in a different study.
The results revealed that pregnant women who had concentrations of vitamin B12 below 259 nanogrammes per one liter of blood, had a risk 2.5 to 3 times higher of having a baby with neural tube defect. And women with the least levels of the vitamin - from 0 to 149 ng/L, which is considered as deficient of B12 - were 5 times more likely to deliver a child with the disorder, compared to women with higher levels of the vitamin.
The experts used special techniques in order to get focused just on vitamin B12 levels and took out the role of folic acid, another B vitamin, a nutrient that is known to help prevent pregnant women from having children with neural tube defects. The authors of the research said that vitamin B12 and folic acid in their combination are connected a few main biochemical reactions, but that a deficit of either B12 or folate leads to a high risk of a neural tube defect.
According to doctors, half of all pregnancies turn out to be unplanned, and therefore they recommend that all women of childbearing age should get at least 400 micrograms of folic acid on a daily basis, even if they are not trying to get pregnant. The government also has required grains and cereals to be fortified with folic acid since 1998.
The study was conducted by Trinity College in Dublin and the Health Board of Ireland in collaboration with the US National Institutes of Health. It is published in the March issue of the journal Pediatrics.