B12 is a vitamin that helps the body maintain essential systems, such as the central nervous system. A B12 deficiency in women can cause symptoms such as fatigue and more severe complications.

The body needs B12 to function healthily, and a B12 deficiency can cause conditions such as severe neurological dysfunction and osteoporosis.

B12 deficiency often affects females of reproductive age and can cause complications during pregnancy and nursing.

This article discusses how B12 deficiency can affect females, its causes, the sources of B12, and how doctors treat a deficiency.

A note about sex and gender

Sex and gender exist on spectrums. This article will use the terms “male,” “female,” or both to refer to sex assigned at birth. Click here to learn more.

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The symptoms of B12 deficiency can vary between people and may be more likely to affect females at certain times, such as during pregnancy or menstruation.

Symptoms of B12 deficiency in women include:

Other signs of B12 deficiency

B12 deficiency can cause anemia, a condition where the body cannot create enough healthy red blood cells. B12-deficiency anemia can cause further complications, such as:

B12 deficiency and anemia can also lead to infertility in females due to abnormal red blood cells and low white blood cell and platelet counts.

Learn more about vitamin B12 deficiency.

If a person believes they may have a B12 deficiency, it is important to speak with a doctor as soon as possible. B12 deficiency symptoms usually begin gradually but can develop to become more serious over time.

More serious complications of B12 deficiency and anemia can lead to serious long-term complications and permanent damage.

B12 supports several systems in the body, including the production of red blood cells, releasing energy from food, and helping the body use folate to create healthy cells.

B12 offers benefits such as:

  • reduced risk of heart disease
  • reduced risk of stroke
  • reduced risk of vision loss
  • supporting neurological function
  • healthy cell growth, repair, and reproduction
  • mood regulation
  • healthy digestion

A person who eats meat, fish, or dairy usually gets enough B12 from their diet. However, individuals who eat a vegetarian or vegan may need to plan their diet more carefully to ensure they get enough B12.

Foods and drinks that contain B12 include:

  • meat (especially organ meat such as liver and kidney)
  • fish
  • eggs
  • milk

Fortified foods contain a synthetic form of B12 and may be helpful for vegans or vegetarians.

Types of fortified foods can include:

  • plant-based milks
  • nutritional yeast
  • breakfast cereals
  • tofu
  • fruit juices
  • vegan spreads
  • dairy-free yogurt

Sometimes, a person may eat foods that supply B12 and still have a B12 deficiency.

There are three main causes of a B12 deficiency:

  • Autoimmune: Certain autoimmune conditions can cause pernicious anemia. This causes the body to produce antibodies that attack a protein called intrinsic factor essential for B12 absorption. This limits the body’s ability to absorb B12 and can lead to a deficiency.
  • Malabsorption: Cells in the stomach known as parietal cells create an intrinsic factor protein essential for B12 absorption. Surgical procedures or conditions that affect the gut, such as gastric bypass surgery or celiac disease, can prevent intrinsic factors from binding to B12 and prevent the body from breaking it down before absorbing the vitamin.
  • Dietary: A person whose diet does not contain enough B12 can develop a deficiency after around 3 years, after which the body may begin to run out of stored B12.

The World Health Organization (WHO) recognizes pregnant or lactating females as one of the most at-risk groups for B12 deficiency. The body requires a greater amount of B12 during these times, and those experiencing deficiency are more likely to experience serious symptoms.

Heavy periods and menopause may also contribute to B12 deficiency in females.

Treating for a B12 deficiency requires building up the levels of B12 in the body and ensuring that the body can absorb the vitamin healthily. The type of treatment a person needs will depend on the underlying cause of their deficiency.

If a person is deficient due to insufficient B12, they may need to organize their diet to include more B12-rich foods or take an oral supplement. For example, a person who follows a vegan diet may need to take an oral supplement to get enough B12.

Those who are pregnant or nursing may need to use oral supplements or another kind of supplementary B12, such as injections.

Those who experience a B12 deficiency due to issues absorbing B12 may require regular B12 injections into the muscle. This may involve weekly injections that decrease to monthly as the body’s store of B12 increases.

Aside from the typical symptoms of B12 deficiency, developing more serious or long-lasting complications is possible. This is the result of a deficiency that remains untreated over a long period.

Possible complications include:

A pregnant or nursing person with a B12 deficiency may pass it to their baby. This can lead to serious complications for the baby, such as failure to thrive, developmental delays, and anemia.

When a person receives treatment for a B12 deficiency, they generally recover well and cease to have symptoms, although they may need to continue to use B12 nutritional supplements. A doctor may need to take regular blood samples initially to ensure the treatment works.

It can take a few weeks or longer for a person to feel better once they begin treatment for a B12 deficiency.

Individuals must ensure they are eating foods containing B12 to prevent developing a B12 deficiency. For those who eat meat and dairy and do not have an underlying issue preventing B12 absorption, this should not be a problem.

For those following a vegetarian or vegan diet, or who are pregnant or nursing, an organized diet that includes food and drinks fortified with B12 is essential. Subsequently, supplementary B12 may be necessary.

The recommended daily intake of B12 for female adults is 2.4 micrograms (mcg). This increases to 2.6 mcg during pregnancy and 2.8 mcg during lactation.

B12 deficiency can cause a range of mild to severe symptoms, such as fatigue, weakness, and confusion. If a person does not receive treatment for their B12 deficiency, they may develop more serious complications or be at greater risk for certain long-term illnesses.

It is important for those who are pregnant or lactating to ensure they get enough B12 from their diet or supplements to avoid becoming deficient or passing a deficiency to their baby.

In most cases, treatment for B12 deficiency is effective, and a person will not continue to have symptoms. However, those who have a condition that affects the body’s ability to absorb B12 may need to continue treatment long-term to manage their B12 levels.