Pregnant women increase their chances of vitamin B12 deficiency if they don’t consume enough meat, milk or eggs. This vitamin is found only in animal products. A deficiency of the vitamin during pregnancy could have dramatic consequences for the foetus.

In an in–depth study of 11,216 pregnancies from 11 countries, researchers have concluded that low levels of vitamin B12 are associated with an increased risk of preterm birth.

“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,” says Tormod Rogne, a medical doctor and intern at Akershus University Hospital near Oslo. The study is part of his doctoral thesis at NTNU’s Department of Public Health and Nursing, completed in December 2016.

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.

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,” Rogne says.

The analysis included 94 per cent of all pregnancies that were part of any published study on B12 levels.

“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.

The study was published in the 20 January 2017 issue of the American Journal of Epidemiology.

So how much dairy does a pregnant vegetarian need? According to Videm, a combination of 3 dl milk and 50–75 grams of cheese (5–8 slices) will do it outside of pregnancy. If you want, you can substitute 80 g (4 tablespoons) cottage cheese for the cheese.

Pregnant women, she says, need a bit more: adding either a glass of milk, a good portion of yogurt or 3–4 extra slices of cheese will provide what is needed by a good margin.