Vitamin B12 During Pregnancy and Breastfeeding

B12 For Babies 

Vitamin B12 During Pregnancy and Breastfeeding

Vitamin B12 plays a key role in a baby’s development. A B12 deficiency is dangerous for babies. How much B12 do I need during pregnancy and breastfeeding?

Vitamin B12 in Pregnancy

Vitamin B12 plays a central role in the development of the nervous system and the brain and for general physical development. An unborn baby in the womb already requires enough vitamin B12 to ensure an optimal development. The baby’s supply of this important vitamin is entirely dependent on the mother’s supply. Thus it is critically important that pregnant women ensure they take enough vitamin B12 every day. 

The vitamin B12 concentration in the placenta and in the bloody of the newborn is around twice as high as the concentration in the blood of the mother – a clear indicator of the importance of a B12 supply in the development phase. 

Pregnancy and a Vitamin B12 Deficiency

A vitamin B12 deficiency during pregnancy, just like a folic acid deficiency, can have severe consequences for the child – in worst cases a termination of the pregnancy, coma or permanent neurological damage.1,2 

A slight vitamin B12 deficiency can usually be accounted for over time by administering vitamin B12 to tackle the existing development difficulties, which can be seen in the children after a few months, through the age-appropriate development of the brain and motor skills. However, the extent to which this corresponds to the optimal development and the consequences that it can have on the baby’s long-term health cannot be clearly stated. 

Vitamin B12 during Breastfeeding

The body, brain and nervous system continues to develop after the birth at an increasing rate, meaning that the daily requirement for breastfeeders is even higher than during pregnancy, as a good vitamin B12 supply for the mother remains enormously important. As early as one month into a baby’s life, many of the foundations for the development of the brain, nervous system and general health are laid. A deficiency at this time can have long term consequences in a child’s life.

Breast milk contains almost exactly as much vitamin B12 as the mother’s blood. Through nutrition, the mother must not only ensure her own supply of vitamin B12, but also that of the infant, meaning a much higher daily requirement. 

Studies carried out on the children of strict vegans and vegetarians, who often show signs of a potential vitamin B12 deficiency, have pointed to an increased risk of development disorders.3-9 Further impairments to the child can occur when the mother suffers from even a mild vitamin B12 deficiency, as numerous scientifically documented cases show. 

Vitamin B12 for Vegan and Vegetarian Mothers

The very drastic findings in the studies above indicate just how real the problem of ensuring a vitamin B12 supply for children of vegan and vegetarian mothers is. Fortunately, it isn’t actually necessary to adjust a vegan lifestyle for the duration of a pregnancy. Sometimes vegetarian and vegan mothers are unsettled by sudden cravings for meat or fish which can set in during the pregnancy.  However, this is simply the body indicating that it is lacking important nutrients such as iron or vitamin B12. 

Alongside taking folic acid supplements, which are recommended for nearly all pregnant women today. doctors advise vegetarians and vegans to take additional vegan vitamin B12 supplements for the duration of the pregnancy and breastfeeding period, to avoid the unnecessary risk of an insufficient supply for the child. 

Gynecologists often carry out blood tests to check iron and folic acid levels during the pregnancy – during these checks, vegans and vegetarians can request a simultaneous B12 check up free of charge. 

Vitamin B12 for Children

A child’s vitamin B12 requirement continues after breastfeeding with the start of complementary feeding. Since many vegan parents understandably prefer their children to follow a vegan diet as well, it is important to be careful here. Most adults make a decision to go vegan during the course of their life, and have consequently already built up a large vitamin B12 body store. However, this isn’t the case for children who are born vegan. 

The supply of vitamin B12 in the womb and through breast milk is enough to cover the baby’s daily need, but remains insufficient when it comes to building up the baby’s B12 storage. Therefore, children are often advised to take a sufficient daily dose of vitamin B12, or else a deficiency can set in very quickly. Thus a supply of vitamin B12 via a corresponding supplement is sensible as early as in the first year of life.

Vitamin B12 sprays have been developed for children which prove particularly effective, since particularly small children often experience difficulty in swallowing capsules or tablets. 

Vitamin B12 Requirements in Pregnancy, Breastfeeding and for Children

Here are the recommended figures for a daily supply of vitamin B12, as given by the DGE.  They assume a very healthy lifestyle and should be considered as the absolute bare minimum required to avoid a deficiency. Just as for adults, the doses in supplements can and should be considerably higher than these suggestions. Possible dosage levels can be seen in the right hand column. 


0 – 4 months


Supplied through breast milk

4 – 12 months


3-10 µg every two days

Small children 

1 – 4 years


3-10 µg every two days
500 µg weekly

4 – 7 years


3-10 µg every two days
500 µg every five days

School children

7 – 10 years


50 µg /day*

10 – 13 years


50 µg /day

Teenagers and adults

From 13 years


150 – 500 µg /day

During pregnancy


250 – 500 µg /day



500 µg /day

*The jump in the dosage level here is because the main absorption mechanism, the intrinsic factor, is limited to a rate of absorption of 1.5 µg per dose. Anything more than this must be absorbed via passive diffusion, through which the body can absorb around 1% of the total dose.

Vitamin B12 – an Essential Vitamin

Vitamin B12 is considered a vital vitamin. If you are unsure about your vitamin B12 levels and supply, avoid taking the risk during pregnancy and breastfeeding and take precautionary vitamin B12 supplements. 


1 Allen, Lindsay H. Vitamin B12 metabolism and status during pregnancy, lactation and infancy. In: Nutrient Regulation during Pregnancy, Lactation, and Infant Growth. Springer US, 1994. S. 173-186.
2 Molloy, Anne M., et al. “Effects of folate and vitamin B12 deficiencies during pregnancy on fetal, infant, and child development.” Food & Nutrition Bulletin 29.Supplement 1 (2008): 101-111.
3 Simsek, Özlem Pelin, et al. “A child with vitamin B12 deficiency presenting with pancytopenia and hyperpigmentation.” Journal of pediatric hematology/oncology 26.12 (2004): 834-836.
4 Sklar, Ronald. “Nutritional vitamin B12 deficiency in a breast-fed infant of a vegan-diet mother.” Clinical pediatrics 25.4 (1986): 219-221.
5 Stollhoff, K., K. H. Bentele, and F. J. Schulte. “Vitamin B12 und Hirnentwicklung.” Aktuelle Neuropädiatrie 1986. Springer Berlin Heidelberg, 1987. 407-411.
6 Lövblad, Karl-Olof, et al. “Retardation of myelination due to dietary vitamin B12 deficiency: cranial MRI findings.” Pediatric radiology 27.2 (1997): 155-158.
7 Codazzi, Daniela, et al. “Coma and respiratory failure in a child with severe vitamin B12 deficiency.” Pediatric Critical Care Medicine 6.4 (2005): 483-485.
8 Weiss, Rachel, Yacov Fogelman, and Michael Bennett. “Severe vitamin B12 deficiency in an infant associated with a maternal deficiency and a strict vegetarian diet.” Journal of pediatric hematology/oncology 26.4 (2004): 270-271.
9 Wighton, M. C., et al. “Brain damage in infancy and dietary vitamin B12 deficiency.” The Medical Journal of Australia 2.1 (1979): 1-3.

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