Researchers looked at 11 studies to understand how vitamin B12 during pregnancy affects a baby’s brain development and thinking skills. Vitamin B12 is important for building a baby’s brain before birth. The review found that when mothers had enough B12 or took B12 supplements during pregnancy, their babies showed better language and thinking skills in the first few years of life. However, scientists say we need more research to be completely sure about these findings, especially from larger studies testing B12 supplements directly.

The Quick Take

  • What they studied: Whether a mother’s vitamin B12 levels during pregnancy affect how well her baby’s brain develops and learns in early childhood
  • Who participated: Scientists reviewed 11 different studies that looked at pregnant women and their babies. Four studies directly tested B12 supplements, while seven studies just measured B12 levels and watched what happened to babies
  • Key finding: Babies whose mothers had good B12 levels or took B12 supplements showed better language and thinking skills up to age 3.5 years. Babies of mothers with low B12 appeared to have slower brain development
  • What it means for you: If you’re pregnant or planning to get pregnant, checking your B12 level might be worth discussing with your doctor. However, more research is needed before doctors can make strong recommendations about B12 supplements for all pregnant women

The Research Details

This is a systematic review, which means scientists searched through medical databases to find all the best studies on this topic. They looked at studies published in PubMed, Scopus, Web of Science, and Embase—basically the biggest libraries of medical research. They found 11 studies total: 4 were randomized controlled trials (where some women got B12 and others got a fake pill to compare) and 7 were observational studies (where scientists just watched what happened without controlling the treatment).

The researchers followed strict guidelines called PRISMA to make sure they did this review the right way. They also checked each study’s quality using special tools to see if the research was done well and if the results were trustworthy. This careful approach helps make sure the conclusions are based on solid evidence.

A systematic review is important because it brings together all the research on one topic instead of looking at just one study. This gives us a bigger, clearer picture of what the evidence shows. Since vitamin B12 is crucial for building a baby’s brain and nervous system, understanding whether mothers need more B12 during pregnancy could help prevent developmental problems in children

This review was registered before it started (which is good practice), and the researchers checked the quality of each study they included. However, the review only found 11 studies, and only 4 were the strongest type (randomized controlled trials). This means the evidence is still somewhat limited. The researchers themselves said we need more and bigger studies to be completely confident in these findings

What the Results Show

The main finding is that maternal vitamin B12 appears to matter for how babies’ brains develop. Babies whose mothers had adequate B12 levels or took B12 supplements showed better performance in language and thinking skills during the first 3.5 years of life compared to babies of mothers with low B12.

Observational studies (where scientists watched what naturally happened) found connections between a mother’s B12 level and her baby’s overall brain development in children under age 2. This suggests that B12 status during pregnancy may have lasting effects on how a child’s brain develops.

The studies looked at different measures of brain development, including how babies learned language, how they solved problems, and how they reached developmental milestones. In most cases, better maternal B12 levels were linked with better outcomes in these areas.

Beyond the main findings, the research suggests that B12 deficiency during pregnancy might be a risk factor that doctors should watch for. Some studies showed that very low B12 levels were associated with delays in reaching developmental milestones. The review also noted that B12 supplementation appeared safe during pregnancy, with no reports of harmful effects from taking supplements

This is actually the first systematic review to specifically look at how maternal B12 affects child brain development and thinking skills. While scientists have known for a long time that B12 is important for the nervous system, nobody had gathered all the research on this specific question before. This review fills that gap and shows that the evidence is pointing in a consistent direction—B12 matters for babies’ brains

The biggest limitation is that there aren’t many studies on this topic yet, especially high-quality studies that test B12 supplements directly. Only 4 out of 11 studies were randomized controlled trials, which are the gold standard for testing whether something actually works. The other 7 studies just observed what happened without controlling who got B12, which makes it harder to be sure B12 was the reason for the differences. Also, the studies measured brain development in different ways, making it tricky to compare results across studies

The Bottom Line

Based on this review, pregnant women should discuss their B12 status with their doctor. If you’re pregnant or planning pregnancy, ask your doctor about checking your B12 level. If you’re low, supplementation appears safe and may help your baby’s brain development. However, confidence in this recommendation is moderate because we need more research. Don’t start supplements without talking to your doctor first, as they can recommend the right dose for you

This matters most for pregnant women and women planning to get pregnant. It’s especially important for vegetarians and vegans, since B12 comes mainly from animal products. People with digestive problems that affect nutrient absorption should also pay attention. If you’re already pregnant, this is worth discussing at your next prenatal visit. This doesn’t necessarily apply to non-pregnant people, though adequate B12 is important for everyone’s health

If a mother starts B12 supplementation during pregnancy, the benefits for the baby’s brain development would likely appear in the first few years of life. Language skills and thinking abilities develop rapidly from birth to age 3, so this is the critical window. You wouldn’t see changes overnight, but over months and years, better B12 status during pregnancy appears linked to better developmental progress

Want to Apply This Research?

  • If pregnant or planning pregnancy, track B12 supplementation daily (if recommended by your doctor) and note the dose. Record any prenatal visits where B12 levels are checked, including the actual B12 level if available. This creates a record to share with your healthcare provider
  • Set a daily reminder to take B12 supplements if your doctor recommends them. Log it in the app each time you take it to build the habit and ensure consistency. If you’re vegetarian or vegan, use the app to track B12-rich foods you eat (fortified cereals, nutritional yeast, plant-based milks) to understand your dietary intake
  • Track prenatal B12 blood tests when done (typically part of routine prenatal care). Note any developmental milestones your child reaches (first words, walking, problem-solving skills) to monitor healthy development. Share this information with your pediatrician at well-child visits to ensure your child is developing on track

This review summarizes scientific research but is not medical advice. Vitamin B12 status and supplementation during pregnancy should be discussed with your obstetrician, midwife, or healthcare provider who knows your individual health situation. Do not start, stop, or change any supplements without consulting your doctor first. This information is for educational purposes and should not replace professional medical guidance. If you have concerns about your B12 levels or your child’s development, contact your healthcare provider.