British experts are testing whether a new supplement taken in early pregnancy could cut the risk of defects including spina bifida.
Women are already urged to take folic acid during the first three months of pregnancy to reduce the chance of a baby suffering neural tube defects. But data suggests folic acid cannot prevent occurrence of all these conditions and some disorders appear to be unresponsive to it.
Now, a team from the research arm of Great Ormond Street Hospital is investigating whether women could take a single daily pill combining the new supplement and folic acid.
One reason why folic acid may not always work is that a genetic "blockage" occurs affecting how it is metabolised in cells. The new supplement includes nucleotides, which are able to bypass this blockage, boosting the effect of folic acid and ensuring the growth of crucial cells.
Tests in mice with the new supplement resulted in an 85% drop in the incidence of neural tube defects. Some conditions that are currently unresponsive to folic acid were also prevented.
Nicholas Greene, professor of developmental neurobiology at the Institute of Child Health (ICH), which is the research partner of Great Ormond Street, said: "We are still in the early stages of this research, but we hope that these promising results in mice can eventually be replicated with human neural tube defects. If it is found to be effective, this nucleotide treatment could boost the effects of folic acid and offer expectant mothers an even more reliable safeguard against relatively common defects like spina bifida."
Neural tube defects affect around one in 1,000 babies in the UK every year and occur if there is a problem with the normal development of the nervous system.
At around 28 days after fertilisation, the developing spinal cord is an open tube but this usually closes. If this process does not occur correctly, spina bifida can result, potentially causing learning difficulties, disability or even an exposed spinal cord.
The Department of Health recommends women take a daily supplement of 400 micrograms of folic acid (also known as vitamin B9) while trying to conceive and for the first 12 weeks of pregnancy. Prof Greene said that, for now, women should continue to take folic acid supplements.
The study, published in the journal Brain, was funded by the Wellcome Trust, Medical Research Council and Newlife Foundation for Disabled Children.