Preparing for Pregnancy

Fertility and Vitamin B12

Vitamin B12 and fertility - wooden board with bread, cheese, eggs and glass of milk

Planning for pregnancy can be a fun, but also daunting, task. You might wonder if you’re getting enough sleep, timing your cycle correctly, or eating the ‘right’ foods. Nutrition is an important factor when trying to conceive. While eating a balanced diet can help you meet your body’s pre-pregnancy needs, there some nutrients that are extra important during this time. One of these is vitamin B12. Keep reading to learn more about fertility and vitamin B12.


Why is Vitamin B12 Important?

Vitamin B12 is a coenzyme that has many important functions in the human body, including building DNA and red blood cells (1), neurological function (1), and ovulation (2). One study found that women who consumed a vitamin B supplement had a greater chance of becoming pregnant and giving birth to a healthy baby (2). A mother with lower levels of B12 has also been associated with preterm birth and low birth weight (3). In addition to helping with conception, consuming enough B12 before pregnancy can help ensure your baby has adequate stores during pregnancy, which is important for their growth and development (3).


Signs of Vitamin B12 Deficiency

Signs and symptoms of B12 deficiency include:

    • Reduced energy
    • Decreased tolerance to exercise
    • Shortness of breath
    • Heart palpitations
    • Swollen tongue
    • Loss of appetite 
    • Changes in stool
    • Constipation
    • Tingling and numb extremities
    • Cognitive changes, such as memory loss (1)

Note: Many different conditions have the same or similar signs and symptoms. Avoid self-diagnosing. If you have any of the symptoms listed above, connect with your healthcare provider


Foods High in Vitamin B12

Vitamin B12 is naturally found in animal products. Plant products don’t contain vitamin B12 naturally (1) but some have B12 added. Sources of B12 include:

    • Muscle meats (e.g., steak, ground beef)
    • Organ meat (e.g., liver)
    • Chicken 
    • Fish
    • Shellfish
    • Eggs
    • Dairy products 
    • Fortified Foods:
      • breakfast cereals 
      • nutritional yeasts
      • plant-based meats
      • plant and nut milks
    • Tempeh

Including these foods regularly can help ensure you are getting enough B12.


Vitamin B12 Supplementation for Fertility

You likely get enough vitamin B12 if you eat meat products, but if you eat mostly or all plant-based foods, supplementation may be beneficial (1). Alternatively, you can look for plant-based foods that are fortified with B12.      

Health Canada recommends the following B12 intake:

    • Non-pregnant women: 2.4 μg/day
    • Pregnant women: 2.6 μg/day
    • During lactation: 2.8 μg/day (4)

If you’re worried that your B12 intake is low, taking a B-complex multivitamin can help ensure all your B vitamin needs are met. If you’re already taking a prenatal vitamin, check to see if it contains B12 before taking additional supplementation. Looking to learn more about how to choose a prenatal vitamin? Check out Choosing a Prenatal Supplement for guidance. 

Note: There is no upper-intake level for vitamin B12. As a water-soluble vitamin, your body excretes any extra daily. Evidence suggests that excessive intake of vitamin B12 from food or supplements does not cause adverse effects (1).


Final Notes from The Nest

Vitamin B12 is important for fertility, a healthy pregnancy, and to support the growth and development of your baby (3). You can often get adequate B12 though including a variety of foods, but sometimes supplementation is necessary. If you would like to learn more about navigating preconception and pregnancy nutrition, visit Our Services page and Book a Consult with one of our Registered Dietitians. 

Article written by Natalie Johnston

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  1. Gibson RS. Principles of nutritional assessment. 2nd ed. New York: Oxford University Press; 2005. 908 p.
  2. Cirillo M, Fucci R, Rubini S, Coccia ME, Fatini C. 5-Methyltetrahydrofolate and vitamin B12 supplementation is associated with clinical pregnancy and live birth in women undergoing assisted reproductive technology. Int J Environ Res. 2021;18:12280. ijerph182312280
  3. Tan A, Sinclair G, Mattman A, Vallance HD, Lamers Y. Maternal vitamin B12 status in early pregnancy and its association with birth outcomes in Canadian mother–newborn Dyads. Br J Nutr. 2021;126(12):1823–31. 
  4. Government of Canada. Prenatal nutrition guidelines for health professionals – background on Canada’s food guide. Ottawa: Her Majesty the Queen in Right of Canada, as represented by the Minister of Health; 2009. 7 p. Available from: