New research suggests another vitamin, one involved in everything from nerve function to DNA production, could play an important role before and during pregnancy, and not just for mothers.

A study published in Annals of Internal Medicine examined whether levels of folate and vitamin B12 in both parents were linked to the likelihood of birth defects in their children.

Folic acid, a form of vitamin B9, has long been recommended before and during pregnancy because it helps prevent neural tube defects, serious conditions affecting the brain and spinal cord.

However, scientists have become increasingly interested in whether other nutrients, including vitamin B12, might also influence the risk of a wider range of birth defects.

Dr. Nikki Ramskill, a women's health doctor who was not involved in the study, told Newsweek that B12 has an "important role from the very earliest stages of a baby's development."

Ramskill said: "It is needed for DNA synthesis and cell division, as well as healthy red blood cell formation and normal neurological development.

"These processes are particularly important during early pregnancy, when cells are dividing incredibly rapidly and the baby's brain, spinal cord and other organs are beginning to form."

What the Study Found

Researchers analyzed data from the Shanghai Preconception Cohort, which tracks the health of parents and children in China. The study included 3,032 couples who had blood samples taken in the four months before conception and nearly 18,000 women who had blood tests during the first four months of pregnancy.

The team measured levels of red blood cell (RBC) folate, which is considered a more accurate indicator of long-term folate status, and vitamin B12. They then tracked birth defects identified through prenatal scans, newborn examinations and medical records for up to one year after birth.

The results showed a clear pattern for vitamin B12. Higher vitamin B12 levels before conception were associated with a lower risk of birth defects in both mothers and fathers.

Among mothers, the predicted rate of birth defects fell as vitamin B12 levels increased, with the lowest rates seen in those with the highest vitamin B12 levels. Fathers showed a similar trend, although the reduction appeared to level off at moderately high vitamin B12 levels.

The findings for folate were less straightforward. Before conception, the relationship between parents' folate levels and birth defects was less clear. But during early pregnancy, higher maternal levels of both folate and vitamin B12 were generally linked to a lower risk of birth defects.

Researchers said the findings add to growing evidence that vitamin B12 may play an important role alongside folic acid in supporting healthy fetal development.

Should Couples Start Taking Vitamin B12 Supplements?

The authors caution that the study found an association rather than proving that low vitamin B12 levels directly cause birth defects. Other factors not included in the analysis may have influenced the results.

They also note that the findings may not necessarily apply to populations outside China, where diets, supplement use and vitamin levels can differ.

Ramskill, founder of The Female Health Doctor Clinic in England, said couples do not need to rush to buy high-dose supplements based on this study alone.

She said that anyone following a restrictive or vegan diet, dealing with conditions that affect nutrient absorption, taking medications that can interfere with vitamin B12 uptake, or who has previously had low B12 levels should consider speaking with a healthcare professional about testing and appropriate supplementation before pregnancy.

Ramskill added that vitamin B12 levels are not always simply "normal" or "deficient," with some people falling into a borderline range where additional tests may be needed to determine whether they have enough usable B12 at a cellular level.

The researchers said women should continue following current guidance to take folic acid before and during pregnancy, while any questions about vitamin supplementation should be discussed with a healthcare professional.

Ramskill concluded that "preconception nutrition shouldn't simply be about taking a generic pregnancy multivitamin once you see a positive test. Ideally, we're thinking about folate, B12 and other key nutrients before conception, looking at dietary intake and individual risk factors, and correcting genuine deficiencies in advance where possible."

Ramskill added that, while preconception health optimization does not happen in every case, particularly given that more than half of pregnancies are unplanned, it remains an important consideration for people of reproductive age whenever the opportunity exists.

Contact Newsweek editors on this story: Charlotte Nisbet and James Debens