Multivitamins in pregnancy: what’s the story?

PREGNANCY bigstock-Pregnant-woman-49284809 - CopyIt is well established that nutrient deprivation during pregnancy is associated with adverse health outcomes for the infant.  The use of supplements, such as multivitamins, minerals and omega-3, taken before and during pregnancy, is not uncommon as reflected in the rise in ‘tailored’ pregnancy products.  Now we are told by BBC media reports that pregnancy multivitamins are a waste of money because most mothers-to-be simply do not need them.[1]  A spokesperson from the Royal College of Midwives, commenting on the research headings, advised women who are either pregnant or thinking of becoming pregnant to simply ensure their diet is healthy and varied to include fresh fruit and vegetables, alongside taking folic acid supplements. Here we give you the nutrition science view…

It is of course common sense for women to plan conception in advance as this would enable them to enter pregnancy well nourished.   In the presence of food fortification and access to nutrient-adequate diets, it could be concluded that ‘additional’ supplementation may result in women exceeding the upper limits for dietary reference intakes; however, according to figures published in the most recent National Diet and Nutrition Survey [1] there are some key nutrients that may be low in the diet of UK women.   For example, only 35% of adults regularly consume the recommended five-a-day portions of fruit and vegetables, food sources of a number of essential nutrients including vitamins and minerals.  Whilst food fortification is a regular occurrence within the UK (which aims to reduce the occurrence of nutrient deficiency), looking at both intake and physiological levels, data indicates there is an increased risk of iron deficiency in women of childbearing age with evidence of intakes below the Lower Reference Nutrient Intake (LRNI) in a substantial proportion of older children and adults for some vitamins and minerals, particularly riboflavin, folate, magnesium, potassium and selenium.

In addition, considering the overwhelming evidence for a role of the omega-3s EPA and DHA for normal foetal growth and development, it is a concern that our average intake of oily fish, which is the predominant source, is a mere 52g and a considerable shortfall from the recommended 140g!  The government’s Scientific Advisory Committee on Nutrition suggests eating a minimum of 450mg per day EPA and DHA, yet the national dietary surveys shows that the national average is about 250mg/day.

Folic acid supplementation during pregnancy is now mandatory and is based on the evidence that folic acid decreases the risk of neural tube defects in the infant; however, meta-analysis data suggests that maternal consumption of prenatal multivitamins containing folic acid is associated with decreased risk for several congenital anomalies, not only neural tube defects, [3] but also a decreased risk for paediatric brain tumours, neuroblastoma and leukaemia. (4)  In addition, a 2015 study showed that increased multivitamin use in the preconception and prenatal periods was associated with a slower rate of growth in infants’ % fat mass in the first 5 months of life (a marker of increased risk of obesity in childhood and early adulthood), providing further evidence that nutrient exposure during pregnancy may have positive benefits for the infant (via a process known as foetal programming). [5] Thus the benefits of additional nutrients cannot be ruled out.

Some expectant mothers may find they flourish during pregnancy, are able to eat well and incorporate a good range of nutrient-rich foods, not only to support their own requirements but the requirements of their developing baby.  For other mothers who are susceptible to the hell of morning sickness, the sight of a banana, tomato or even some peas could have them rushing for the loo or the nearest bucket.

So, for the expectant mothers who wish to consider topping up their diet during pregnancy, what should practitioners advise regarding supplements and what should clients avoid?

  1. A ‘top up’ should mean a top up. Too many companies are manufacturing supplements with ‘mega’ doses of nutrients which, quite simply, are not needed and do not provide additional benefits over lower doses (the majority of excess supplemental B-vitamins and other water-soluble vitamins are simply passed straight out in the urine!).  It is the mega-dosing that is of issue as this could in theory increase the risk of exceeding the upper limits for dietary reference intakes.
  2. Choose split dosing over a ‘one-a-day’ dose. Have you ever opened a multivitamin and mineral and gasped at the size of the tablet/capsule?  Many companies make the ‘mistake’ of offering their consumers the ‘convenience’ of the simple one-a-day dose.  Our bodies are not designed to cope with the absorption and uptake of high levels of nutrients in one sitting!  Would you ever recommend a client sit down and eat an entire day’s fruit and vegetable intake in the space of 10 minutes? Choosing a supplement that offers nutrients in small tablets as a split dose (say 1-3 a day) not only optimises uptake but also gives you and your client a choice about their daily dose.
  3. Opt for slow release. Again, our bodies are not designed to cope with the absorption and uptake of high levels of nutrients in one sitting.  By choosing a supplement that incorporates slow release delivery into the formula you’ll be ensuring that those precious nutrients don’t just get ‘dumped’ into the body in one hit.  Interestingly, the more B12 is taken in one go, the less is absorbed because the pathways that are involved in uptake become saturated rather quickly.  Taking B12 as part of a slow release formula means that it’s more likely to get taken up into the body.
  4. Choose bioavailable nutrient forms. Not all manufacturers use what are known as ‘body ready’ forms as these ingredients tend to be more expensive. Standard folic acid supplementation, for example, simply results in an accumulation of unmetabolised folic acid (UMFA) which has no biological function and whose effects are not yet known. Quatrefolic® provides the metabolic reduced folate form utilised and stored in the human body, as (6S)-5-methyltetrahydrofolate, and may benefit certain genetic defects that influence folate metabolism.  Vitamin B6 exists in 6 forms but only the pyridoxal-5-phosphate form has cofactor activity, and as with many B-vitamins, riboflavin must be converted to its active form – riboflavin-5-phosphate – in order for it to be utilised by the body. Methylcobalamin is the natural form of vitamin B12, whereas cyanocobalamin (the cheaper form of vitamin B12 found in abundance in most vitamin B-complex supplements) is a synthetic source of vitamin B12.  The list goes on, but it is likely that if your supplement provider uses these active forms of nutrients then they will prioritise efficacy over profit for the other nutrients too.

The use of supplements is a personal choice for everyone.  By recognising our own potential dietary weaknesses and shortfalls, and being able to recognise a quality supplement you can help your clients make the appropriate choices.


  3. Goh YI, Bollano E, Einarson TR, Koren G.Prenatal multivitamin supplementation and rates of congenital anomalies: a meta-analysis. J Obstet Gynaecol Can. 2006 Aug;28(8):680-9. Review.
  4. Goh YI, Bollano E, Einarson TR, Koren G.Prenatal multivitamin supplementation and rates of pediatric cancers: a meta-analysis. Clin Pharmacol Ther. 2007 May;81(5):685-91. Epub 2007 Feb 21. Review.
  5. Sauder KA, Starling AP, Shapiro AL, Kaar JL, Ringham BM, Glueck DH, Dabelea D. Exploringthe association between maternal prenatal multivitamin use and early infant growth: The Healthy Start Study. Pediatr Obes. 2015 Dec 11.


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Dr Nina Bailey

About Dr Nina Bailey

Nina is a leading expert in marine fatty acids and their role in health and disease. Nina holds a master’s degree in Clinical Nutrition and received her doctorate from Cambridge University. Nina’s main area of interest is the role of essential fatty acids in inflammatory disorders. She is a published scientist and regularly features in national health publications and has featured as a nutrition expert on several leading and regional radio stations including SKY.FM, various BBC stations and London’s Biggest Conversation. Nina regularly holds training workshops and webinars both with the public and health practitioners.