Pregnancy Second & Third Trimester

Vitamin B12 in Pregnancy: What You Need to Know

by Nikki Warren on Feb 13, 2024

Vitamin B12 in Pregnancy: What You Need to Know

Vitamin B12 is an important nutrient for our health and wellbeing. It plays a role in both your baby’s health and your own health during pregnancy. It's a good idea to  monitor your vitamin B12 levels in pregnancy for deficiency.

Managing vitamin B12 deficiency during pregnancy may involve B12 injections, supplements and increasing foods rich in B12. Taking a high-quality prenatal multivitamin alongside a healthy diet can help maintain a healthy pregnancy.


Here's why Vitamin B12 matters in pregnancy:

  • Vitamin B12 in pregnancy is important for healthy foetal brain development.
  • Symptoms of vitamin B12 deficiency may include fatigue, brain fog, anaemia or numbness/tingling in hands or feet.
  • Management of vitamin B12 in pregnancy may involve increasing dietary B12, B12 injections or supplements.


Roles of Vitamin B12 in Pregnancy

Vitamin B12 is important for healthy foetal nervous system and brain development. Emerging research shows that B12, along with folate, can lower the chance of birth defects that affect the nervous system, like spina bifida. B12 plays a role in cell replication and helps to regulate foetal growth.

B12 is important for your health as the mother in pregnancy, too. B12 plays a role in adult brain and nervous system health, memory, learning, moods, and energy levels. B12 is important for healthy red blood cells and circulation.


Taking Prenatal Vitamins with Anaemia

Anaemia is a common problem that women may have during pregnancy. Anaemia during pregnancy can be from iron deficiency or B12 deficiency or both. There are different types of anaemia including microcytic and megaloblastic anaemia.

Microcystic anaemia is where your red blood cells are too small. Megaloblastic anaemia is where your red blood cells are too large and is more common with a B12 deficiency. Both types of anaemia cause poor delivery of oxygen and nutrients to your body’s tissues.

Your healthcare provider can do some blood tests to assess this. If mean cell volume (MCV) and homocysteine levels are high, this may indicate a B12 deficiency. They will also test your iron levels too alongside a full blood count.

Some women ask if it's okay to keep taking their prenatal vitamin if they're anaemic. Your healthcare provider will recommend continuing to take your prenatal vitamin alongside treatment for your B12 deficiency.


Vitamin B12 Deficiency & Management During Pregnancy

Other B12 deficiency symptoms other than anaemia may include:

  • Fatigue
  • Breathlessness
  • Nervous system symptoms (numbness, tingling, poor balance)
  • Poor concentration or memory
  • Paleness
  • Mood symptoms (low moods or anxiety and poor sleep)

Some women may be more likely to develop a vitamin B12 deficiency than others. Following a vegan or vegetarian diet may lead to low dietary intake of B12.

While poor absorption of B12 can also lead to low levels. Poor absorption can occur from digestive conditions (IBD, IBS, coeliac disease).

If you have an MTHFR genetic mutation this can impact your body’s ability to metabolise B12. Many people may have MTHFR genetic mutations. That’s why we choose to use active folate in our prenatal vitamins instead of folic acid.

Being aware of the impacts of a B12 deficiency during pregnancy is important. Health knowledge empowers you to have the healthiest pregnancy and baby possible.

A B12 deficiency during pregnancy may increase the risk of low birth weight and preterm births and miscarriages. Women may be at a higher risk of pre-eclampsia and gestational diabetes and weight gain during pregnancy with a B12 deficiency.

You can easily treat and manage a vitamin B12 deficiency with your healthcare provider, and it is very common. Management often involves increasing dietary intake of foods rich in B12, high quality B12 supplements and potentially B12 injections by your health care provider.


B12 Injections & Supplements While Pregnant

There are different forms of vitamin B12, so choosing the best prenatal vitamin is important.

Hydroxocobalamin is the type of vitamin B12 found in food. A cheap form of B12 is cyanocobalamin, which is found in some supplements. The two active forms of B12 are methylcobalamin and adenosylcobalamin. Hydroxocobalamin converts into both of the two active forms of B12.

It is important to increase your dietary B12 intake alongside taking your supplements for optimal pregnancy health. Foods rich in B12 include mushrooms, nutritional yeast and animal products (meat, dairy, butter, eggs).

Your healthcare provider may also recommend B12 injections if needed to treat your B12 deficiency during pregnancy. Hydroxocobalamin is the form of B12 used in B12 injections and studies show that oral intake from supplements has equivalent absorption to injections.

In summary, foetal and maternal health and wellbeing require vitamin B12. You can raise your B12 levels by eating certain foods, taking supplements, or an injection from your healthcare provider. Prenatal vitamins can support your nutritional intake alongside a healthy diet during pregnancy. 

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