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5 Reasons Why Vitamin B12 Deficiency Harms Fertility

Having troubles conceiving a child is stressful, but tackling fertility issues one problem at a time can significantly improve your fertility. The first step towards greater fertility is an understanding of why certain things (such as B12) are important for finally conceiving a child and adding a new member to your family.

Symptoms of vitamin B12 deficiency

  • Infertility
  • Insomnia
  • Constipation
  • Emotional disorders
  • Skin problems
  • Dizziness
  • Numbness or tingling in hands or feet
  • Grey hair before 30
  • Fatigue
  • Weakness
  • Weight loss
  • Vision problems
  • Hearing loss

5 Reasons Why Vitamin B12 Deficiency Harms Fertility

Lower female infertility

If you did not already know, vitamin B12 is a vital component for methylation and vitamin B12 deficiency can lead to high homocysteine levels. Studies show that vitamin B12 deficiency creates an imbalance in one carbon metabolism — a process involving folate, MTHFR, and homocysteine — that decreases female fertility and compromises the ability for fertilized embryos to implant themselves in the uterus. (1) High homocysteine levels are associated with a variety of fertility and health problems. We are written about homocysteine levels at length in articles you can find here and more about MTHFR in preconception and pregnancy here.

Increased risk of miscarriage

Miscarriage is common among people who are deficient in vitamin B12, due to associated high homocysteine levels and methylation problems. (2) Elevated homocysteine levels drastically increase the risk of developing blood clots during pregnancy, and in many cases, clots that occur during pregnancy are what leads to miscarriage.

Irregular ovulation

A regular ovulatory cycle is important for fertility because if gives you a greater chance at accurately predicting when you are most fertile. If vitamin B12 deficiencies are chronic, women seeking to become pregnancy will also experiences inconsistent ovulatory cycles, changes to the development of the ovum, and experience chronic implantation issues. (2)

Increased risk of neural tube defects

Neural tube defects are more prevalent in women with vitamin B12 deficiencies due to how closely vitamin B12 relates to the folate cycle. Vitamin B12 and the active form of folate is needed to convert homocysteine to methionine. Without enough vitamin B12 homocysteine begins to rise leading to previously mentioned fertility problems, but also methylation issues arise due to low methionine levels. A growing fetus requires a lot of methylation to coordinate its growth effectively, especially its nervous system, and without adequate folate and vitamin B12 levels there is an increased risk of developing neural tube defects. (3)

Male infertility

Women are not the only ones who need to worry about the effect vitamin B12 deficiency can have on their fertility. Men with low vitamin B12 levels are likely to be one of the causes of idiopathic male infertility, especially within men who have the MTHFR C667T genetic mutation. (4)

What can be done about vitamin B12 deficiency to prevent fertility issues?

The easiest way to prevent vitamin B12 deficiency is to supplement with Vitamin B12. Although not all vitamin B12 supplements are created equal, you can read more about vitamin B12 supplements and vitamin B12 deficiency in our article here.

If you want a quick, easy, and sure fire way to ensure you have sufficient vitamin B12 levels, and help prevent further infertility, than we recommend taking our Starter Kit A “METHYL”. It will give you everything you need for vitamin B12, and a lot more!


  1. Laanpere, M., Altmäe, S., Stavreus-Evers, A., Nilsson, T. K., Yngve, A., & Salumets, A. (2010). Folate-mediated one-carbon metabolism and its effect on female fertility and pregnancy viability. Nutrition reviews, 68(2), 99-113.
  2. Bennett, M. (2001). Vitamin B12 deficiency, infertility and recurrent fetal loss. The Journal of reproductive medicine, 46(3), 209-212.
  3. Czeizel, A. E., & Dudás, I. (1992). Prevention of the first occurrence of neural-tube defects by periconceptional vitamin supplementation. New England journal of medicine, 327(26), 1832-1835.
  4. Murphy, L. E., Mills, J. L., Molloy, A. M., Qian, C., Carter, T. C., Strevens, H., ... & Levine, R. J. (2011). Folate and vitamin B12 in idiopathic male infertility. Asian journal of andrology, 13(6), 856.

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