This is why vitamin B12 is so important in pregnancy

How to ensure you're meeting your B12 requirements.
Written by
Gemma Kaczerepa
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Last updated on
February 28, 2024
min read
Why Is Vitamin B12 So Important In Pregnancy? | Kin Fertility
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We’re pretty sure we can all agree that pregnancy takes a hell of a toll on our bodies. Sore and swollen everything, peeing every 10 minutes, morning sickness (which should really be renamed ‘24/7 sickness’) and constant exhaustion. 

On top of the more obvious impacts of pregnancy, your body also undergoes a bunch of changes internally. One of those is the way your body metabolises nutrients and its resulting nutritional needs.

There’s a lot going on when you’re growing a tiny human, so naturally, you require a tonne of extra nutritional support. Among the most important nutrients needed for a healthy pregnancy is vitamin B12.

But what exactly is vitamin B12 and why is it such a fundamental nutrient when you’re preggers? And if you’re low in the stuff, how can you boost your levels? Here’s the 411 on B12.

What is vitamin B12?

Vitamin B12 is part of the group of B vitamins, also known as the B complex. It’s a water-soluble vitamin found in a bunch of foods but is also added to some foods and can be taken as a supplement.

You might also hear B12 referred to as cobalamin. Vitamin B12 is naturally present in animal food sources, including red meat, poultry, fish, shellfish, liver, dairy products and eggs.

It’s also used to fortify plant-based foods like plant milks and plant yoghurts, tofu, nutritional yeast, cereals and fruit juice.

So, what role does vitamin B12 play? A damn important one. Vitamin B12 is a crucial part of the DNA-making process and supports blood and nerve health. When it comes to pregnancy, vitamin B12 becomes even more critical.

It’s fundamental to the development of your baby and helps prevent adverse health outcomes, including neural tube defects, and complications like preeclampsia, miscarriage and low birth weight.

Why do you need vitamin B12 during pregnancy?

Adequate vitamin B12 consumption is especially important during pregnancy. Together with folic acid, B12 supports your baby’s spinal cord development and cognitive outcomes and helps create DNA. 

Unfortunately, though, pregnant people are at an increased risk of vitamin B12 deficiency. This is because the increased nutritional demands of pregnancy can very easily lead to a drop in vitamin B12 levels. 

Without enough B12, an unborn baby is at increased risk of developing permanent neurological and developmental issues; defects of the brain, spine or spinal cord; and intrauterine growth retardation, where the baby doesn’t grow as it should and often comes out with a low birth weight.

In terms of pregnancy outcomes, a vitamin B12 deficiency may lead to preeclampsia or miscarriage in early pregnancy.

By keeping up your vitamin B12 levels, you can help prevent neural tube defects and serious problems like spina bifida (a deformation of the spine and spinal cord), anencephaly (where the brain and spinal cord don’t form correctly) and encephalocele (where the brain protrudes from the skull).

You can also help ward off abnormalities in your baby’s nervous system, along with pregnancy complications like preeclampsia, low energy and mood, and stress.

Can you take B12 while pregnant?

Absolutely! For many pregnant women, a nutritious diet filled with B12-rich foods can usually help prevent vitamin B12 levels from dropping — whether these foods are a natural source or fortified. 

But if you already had a B12 deficiency before pregnancy, or you’re on a strictly vegetarian or vegan diet and not eating fortified plant-based foods, your doctor may recommend taking a supplement.

Vitamin B12 is considered to be low toxicity, but you should always chat to your doctor before taking a vitamin B12 supplement on top of your regular prenatal vitamins. 

How much vitamin B12 do pregnant women need?

Like many other vitamins and minerals, your body requires more vitamin B12 when you’re pregnant or breastfeeding.

Non-pregnant women need 2.4 micrograms (mcg) of vitamin B12 per day, whereas pregnant women need 2.6 mcg per day and breastfeeding parents need slightly more at 2.8 mcg per day.

However, studies have also shown that 500mcg doses of vitamin B12 at around 2% can be particularly useful in boosting the body's B12 stores, in order to ensure adequate levels for healthy in-utero brain development [18].

That's why, in our new and improved prenatal formula, we increased the amount of B12 — to optimise your body's stores of this crucial vitamin.

Signs you don't get enough vitamin B12

Quite often, there are very few symptoms associated with a vitamin B12 deficiency — or even none at all. But if your deficiency is severe, you may experience the following:

  • Fatigue
  • Weakness
  • Lightheadedness
  • Dizziness
  • Poor memory
  • Stomach issues, including constipation and diarrhoea
  • Pale or yellow skin
  • Inflammation, swelling or pain in the tongue
  • Tingling or numbness in the hands or feet
  • Increased heart rate or breathing
  • Anemia

To gauge your vitamin B12 status, your doctor will usually assess your symptoms, diet (especially if you’re vegetarian or vegan) and medical history, and may perform a blood test to check vitamin B12 serum levels. 

Generally, it’s not necessary to check your vitamin B12 levels via a blood test unless risk factors are present, including being vegan or vegetarian, having a family history of vitamin B12 deficiency or pernicious anaemia (a condition caused by poor ability to absorb vitamin B12), or suffering from another disorder that can make it difficult for your body to absorb vitamin B12 such as Crohn’s disease or coeliac disease.

How to boost vitamin B12 levels while pregnant

Keen to keep your vitamin B12 levels stable, or wondering how to safely increase them while pregnant? Here’s what you can do.

Eat vitamin B12-rich foods

A balanced diet is key to a healthy pregnancy and one rich in foods that contain high amounts of vitamin B12 can help sustain your levels. 

For pregnant people who eat animal products, this could include tinned tuna (roughly 2.75 mcg of vitamin B12 per tin) Atlantic salmon (2.6 mcg per 85g serving), steak or lean beef mince (the latter has 2.4 mcg per 85g serving), low-fat milk (1.3 mcg per cup) and eggs (1.1 mcg per two eggs). 

While liver is another fantastic source of vitamin B12, it’s best avoided during pregnancy as it contains high quantities of retinol, a form of vitamin A.

Excessive amounts of the stuff can cause problems for your unborn baby. And, always make sure to stick to the recommended limits for pregnancy when it comes to foods like seafood and meat.

If you're on a vegetarian or vegan diet, you can still get some vitamin B12 from the foods you eat.

Examples of these foods include nutritional yeast (anywhere between 8.3 and 24 mcg of vitamin B12 per quarter cup, depending on the brand), fortified breakfast cereals (0.6 mcg per serving) and other fortified foods like plant milk and juice.

Take a comprehensive prenatal vitamin

Prenatal vitamins bundle many of the vitamins and minerals your body needs while it supports a growing foetus — such as folate, iron, iodine, zinc, vitamin C, vitamin D, and of course, multiple B vitamins including B12.

The advantage of taking prenatal vitamins is that you get the right amount of each nutrient in every dose.

Add a vitamin B12

Even with a good prenatal vitamin, your doctor may still recommend an additional vitamin B12 supplement — especially if you’re vegan or vegetarian, or have a condition like Crohn’s disease, coeliac disease, irritable bowel disease or another autoimmune issue that makes it tricky for your body to properly absorb vitamin B12.

Your doctor will advise the right dosage for dietary supplements depending on your circumstances.

Does your newborn baby need vitamin B12 too?

So, what happens once bub comes out? Can you give up the steak, seafood and supplements? Not so fast. You should still aim to maintain healthy vitamin B12 levels by getting at least 2.8 mcg per day — this is the amount recommended for breastfeeding women. 

Your brand-new bundle of joy needs vitamin B12, too. Their body uses it to nurture brain development and to create healthy red blood cells, and an untreated deficiency can lead to irreversible brain damage.

Up to the age of six months old, your baby should get about 0.4 mcg of vitamin B12 per day, and between seven and 12 months, they’ll require 0.5 mcg per day.

As long as you’re getting enough vitamin B12, it’s likely your baby will receive adequate amounts via your breast milk. Formula also usually contains the right amount of vitamin B12 for your baby. 

If you’re deficient, though, they could end up deficient, too. That’s why maintaining a diet rich in vitamin B12-containing foods is important, or at least continuing to take a nutritional supplement.

If you don’t consume animal products, make sure to chat to your doctor about supplementation so that you and bub are getting enough of this all-important vitamin.

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