London, Jan 26 (IANS): Vegetarian mothers who do not eat meat, dairy products or eggs may be particularly vulnerable in developing B12 deficiency during pregnancy which is likely to increase the risk of preterm births, a study has found.

Our body cannot produce Vitamin B12 itself, it is found only in animal products such as meat, milk and eggs.

"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 from Akershus University Hospital in Norway.

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

Premature birth -- baby born before 37 weeks of pregnancy -- is the leading cause of death in children under the age of five around the world.

"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," Rogne added.

Those who do not consume meat, dairy products or eggs should substitute these food products with adequate supplementation, the researchers said.

"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," Rogne said.

For the study, published in the American Journal of Epidemiology, the team analysed 11,216 pregnancies from 11 countries.