Does taking folic acid increase the incidence of twins?
There has been some debate and conflicting studies about whether taking folic acid pre-conceptually could increase the chance of having twins. A study in Sweden in the 1990s found a higher incidence of multiple births among women taking folic acid. However, this could be attributed to other factors, such as a greater number of women undergoing fertility treatment, which carries an increased probability of twins. Also, subsequent studies have refuted these findings; in 2003, the medical journal The Lancet reported on a large-scale study in China that found there was no significant difference in the number of women who had taken folic acid carrying twins.
