Low folate levels in early pregnancy were associated with increased rates of childhood hyperactivity and peer problems, according to a study with 100 mothers and their children followed for almost nine years.
Scientists from the University of Southampton and University College London’s Institute of Child Health propose that the low folate levels impair the development of the brain in the foetus, and early pregnancy is a critical time for brain development.
“To our knowledge, this is the first study in humans to provide evidence for associations of maternal folate with behavioural outcomes in the offspring, and it is the first study to demonstrate a putative pathway via foetal head growth,” wrote the researchers in the Journal of Child Psychology and Psychiatry.
B for baby benefits
An overwhelming body of evidence links folate deficiency in early pregnancy to increased risk of neural tube defects (NTDs) - most commonly spina bifida and anencephaly - in infants. Most NTDs occur within the first 22 to 28 days of pregnancy, when the mother-to-be is not aware she is even pregnant.
Folic acid supplements after this time are too late to prevent neural tube defects and therefore fail to benefit women with unplanned pregnancies - more than half of all pregnancies in the US.
This connection led to the 1998 introduction of public health measures in the US and Canada, where all grain products are fortified with folic acid - the synthetic, bioavailable form of folate.
Preliminary evidence indicates that the measure is having an effect with a reported 15 to 50 per cent reduction in NTD incidence. A total of 51 countries now have some degree of mandatory fortification of flour with folic acid.
However, similar measures in other countries, including the UK where the new study was based, have been opposed by concerns that the folate/folic acid may mask vitamin B12 deficiency, which leads to a form of neurological problems.
Led by Southampton’s Dr Wolff Schlotz, the researchers recruited 100 mothers in early pregnancy and took blood samples to measure folate levels, and the followed them for an average of 8.75 years. The mothers reported on their children's behaviour using the Strengths and Difficulties Questionnaire.
The results showed that low maternal levels of folate were associated with both higher childhood hyperactivity and peer problems scores.
“Although the associations are small and residual confounding is possible, our data provide preliminary support for the hypothesis that lower folate status in early pregnancy might impair foetal brain development and affect hyperactivity/inattention and peer problems in childhood,” wrote Dr Schlotz and his co-workers.
Dutch researchers reported in the British Journal of Nutrition in September 2009 that the children of mothers who took folic acid supplements during pregnancy were better at internalising and externalising problems, compared to the children of mothers who did not take supplements.
Source: Journal of Child Psychology and Psychiatry
May 2010, Volume 51, Issue 5, Pages: 594-602
“Lower maternal folate status in early pregnancy is associated with childhood hyperactivity and peer problems in offspring”
Authors: W. Schlotz, A. Jones, D.I.W. Phillips, C.R. Gale, S.M. Robinson, K.M. Godfrey