Effect of B vitamins and genetics on success of in-vitro fertilisation.

摘要

In their prospective cohort study (May 6, p 1513),P Haggarty and colleagues conclude that women likely to have a successful pregnancy via in-vitro fertilisation (IVF) should be encouraged to exercise caution whenusing folic acid supplements because of an associated higher incidence of twin births. The risks related to multiple pregnancies are well known2 and there is a growing consensus that twins are a suboptimum outcome of IVF treatment which should be avoided.3Haggarty and colleagues report that 89% of the study population received two embryos and 2% received three. Many European centres are now doing single embryo transfer in more than 50% of cases, and report vastly reduced twin pregnancy rates while maintaining satisfactory pregnancy rates. However, in most countries, multiple embryo transfer remains standard practice. If the problem of multiple pregnancy in IVF is to be properly addressed, opinion leaders need to emphasise that the solution lies in transferring a single embryo, and not in manipulating nutritional supplements.Moreover, generating a "fear of folate" could have detrimental effects on fertility treatment outcomes. Besides the well known importance of folic acid supplementation in preventing several congenital abnormalities, it might also improve gamete quality and increase conception rates in subfertile couples.5