Folic acid does not increase chances of twins
women who take folic acid supplements during pregnancy do not have
an increased likelihood of having a multiple birth, according to
the results in this week's issue of The Lancet.
A Chinese population-based study provides strong evidence that women who take folic acid supplements during pregnancy do not have an increased likelihood of having a multiple birth, according to the results in this week's issue of The Lancet.
Folic acid supplements are recommended for women of childbearing age to prevent neural tube defects - such as spina bifida and anencephaly - in their children. However, results from some small studies have suggested that consumption of vitamins containing folic acid during pregnancy can lead to an increased chance of having a multiple pregnancy - with associated increased risk of complications and poorer health outcomes of infants.
Robert J. Berry from the Centers for Disease Control and Prevention, Atlanta, USA, and colleagues from Peking University Health Science Centre, Beijing, China, assessed the incidence of multiple births in around 240,000 Chinese women who used 400 micrograms daily of folic acid supplements as part of a community health campaign to prevent neural tube defects.
The investigators report that women who used supplements before and during early pregnancy did not have an increased likelihood of multiple births compared with women who did not use folic acid supplements - the rate of multiple births was 0.59 per cent for women who took folic acid and 0.65 per cent for women who did not, a difference found not statistically significant.
Robert J Berry commented: "Our findings suggest that consumption of 400 micrograms of folic acid alone per day, before and during early pregnancy, does not increase a woman's likelihood of having a multiple birth, whether taken before the estimated date of ovulation, around the estimated time of fertilisation, or after conception."
The news will be welcome to the many scientists who support the idea of folic acid fortification of foods, such as cereals, so that women have a higher folate content in their diets. This has proven successful in countries such as the US and Canada, but so far Europe has been reluctant to follow suit, citing the side effects, as too great a risk. Folic acid has also been shown to lower homocysteine levels, a risk factor for cardiovascular disease.
