Vitamin B12 deficiency may up preterm birth risk: study

In countries like India where vegetarian diets predominate, women are at an increased risk of developing vitamin B12 deficiency during pregnancy which may increase their risk of preterm birth, a new study has warned.

Researchers at Norwegian University of Science and Technology (NTNU) carried out an in-depth study of 11,216 pregnancies from 11 countries.

In countries where people eat high levels of animal products, such as Norway and numerous Western countries, only a small percentage of pregnant women have a vitamin B12 deficiency.

"In countries where vegetarian diets predominate, such as in India, the percentage of pregnant women with B12 deficiency can exceed two thirds," said Tormod Rogne, a medical doctor and intern at Akershus University Hospital in Norway.

Vitamin B12 is necessary for the body's vital functions, including the production of red blood cells and cellular metabolic energy.

B12 deficiency can cause anaemia and severe damage to the nervous system. The body cannot produce the vitamin itself.

Globally, low birth weight and preterm births cause half of all infant deaths in the first 28 days after birth. The diet of a pregnant woman is vitally important for her foetus and pregnancy.

"Vitamin B12 is an essential nutrient found only in products of animal origin such as meat, milk and eggs. Pregnant women who consume too few animal-derived foods increase their risk of developing a vitamin B12 deficiency," said Rogne.

"Low levels of vitamin B12 in pregnant women did not appear to affect the newborn's birth weight. But we did find that vitamin B12 deficiency during pregnancy was associated with a 21 per cent increased risk of giving birth prematurely," said Rogne.

The results were independent of whether the countries had high, middle or low average incomes.

Rogne stresses that it is important to remember that there may be other reasons for the apparent link between vitamin B12 deficiency and preterm births.

"Low blood concentrations of vitamin B12 may be related to other factors, such as malnutrition and poverty, which can also affect birth weight and length of pregnancy," he said.

"Although we found that vitamin B12 deficiency is associated with an increased risk of preterm birth, we know very little about the effects of taking vitamin B12 supplements during pregnancy," he added.The study was published in the American Journal of Epidemiology.