Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

An infant and mother with severe B12 deficiency: vitamin B12 status assessment should be determined in pregnant women with anaemia


The vitamin B12 status of infants depends on maternal B12 status during pregnancy, and during lactation if breastfed. We present a 9-month-old girl who was admitted to the metabolic unit for assessment of developmental delay. She was exclusively breastfed and the introduction of solids at 5 months was unsuccessful. Investigations revealed pancytopenia, undetectable B12 and highly elevated methylmalonic acid and homocysteine. Methylmalonic acid and homocysteine normalised following B12 injections. Marked catch-up of developmental milestones was noted after treatment with B12. Investigations of parents showed normal B12 in the father and combined B12 and iron deficiency in the mother. Maternal B12 deficiency, most likely masked by iron deficiency, led to severe B12 deficiency in the infant. Exclusive breastfeeding and a subsequent failure to wean exacerbated the infant’s B12 deficiency leading to developmental delay. This case highlights the need for development of guidelines for better assessment of B12 status during pregnancy.

This is a preview of subscription content, access via your institution

Access options

Rent or buy this article

Get just this article for as long as you need it


Prices may be subject to local taxes which are calculated during checkout


  1. Bjørke-Monsen AL, Ueland PM . Cobalamin status in children. J Inherit Metab Dis 2011; 34: 111–119.

    Article  Google Scholar 

  2. Bjørke-Monsen AL, Refsum H, Markestad T, Ueland PM . Cobalamin status and its biochemical markers methylmalonic acid and homocysteine in different age groups from 4 days to 19 years. Clin Chem 2003; 49: 2067–2075.

    Article  Google Scholar 

  3. Bjørke-Monsen AL, Torsvik I, Saetran H, Markestad T, Ueland PM . Common metabolic profile in infants indicating impaired cobalamin status responds to cobalamin supplementation. Pediatrics 2008; 122: 83–91.

    Article  Google Scholar 

  4. Gherasim C, Lofgren M, Banerjee R . Navigating the B(12) road: assimilation, delivery, and disorders of cobalamin. J Biol Chem 2013; 288: 13186–13193.

    Article  CAS  Google Scholar 

  5. Bjørke-Monsen AL . Is exclusive breastfeeding ensuring an optimal micronutrient status and psychomotor development in infants? Clin Biochem 2014; 47: 714.

    Article  Google Scholar 

  6. Torsvik IK, Ueland PM, Markestad T, Midttun Ø, Bjørke-Monsen AL . Motor development related to duration of exclusive breastfeeding, B vitamin status and B12 supplementation in infants with a birth weight between 2000-3000 g, results from a randomized intervention trial. BMC Pediatr 2015; 15: 218.

    Article  Google Scholar 

  7. National Collaborating Centre for Women's and Children's HealthAntenatal care for uncomplicated pregnancies. CG62. 1-3-2008. National Institute for Health and Clinical Excellence: London, UK.

  8. Carmel R . Biomarkers of cobalamin (vitamin B-12) status in the epidemiologic setting: a critical overview of context, applications, and performance characteristics of cobalamin, methylmalonic acid, and holotranscobalamin II. Am J Clin Nutr 2011; 94: 348S–358.

    Article  CAS  Google Scholar 

  9. Murphy MM, Molloy AM, Ueland PM, Fernandez-Ballart JD, Schneede J, Arija V et al. Longitudinal study of the effect of pregnancy on maternal and fetal cobalamin status in healthy women and their offspring. J Nutr 2007; 137: 1863–1867.

    Article  CAS  Google Scholar 

  10. Honzik T, Adamovicova M, Smolka V, Magner M, Hruba E, Zeman J . Clinical presentation and metabolic consequences in 40 breastfed infants with nutritional vitamin B12 deficiency—what have we learned? Eur J Paediatr Neurol 2010; 14: 488–495.

    Article  Google Scholar 

Download references


We would like to thank the parents for their consent in submitting this report for publication. We also would like to thank the reviewers for their helpful comments.

Author information

Authors and Affiliations


Corresponding author

Correspondence to A Sobczyńska-Malefora.

Ethics declarations

Competing interests

The authors declare no conflict of interest.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Sobczyńska-Malefora, A., Ramachandran, R., Cregeen, D. et al. An infant and mother with severe B12 deficiency: vitamin B12 status assessment should be determined in pregnant women with anaemia. Eur J Clin Nutr 71, 1013–1015 (2017).

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:


Quick links