Folate Levels and Pregnancy Rate in Women Undergoing Assisted Reproductive Techniques: a Systematic Review and Meta-analysis.

Maternal nutrition is believed to be closely related to reproductive success and the importance of folate in the reproductive process and its involvement in fundamental biological systems are well known. The present systematic review and meta-analysis will focus on two main aspects: level of folate in women undergoing infertility treatments and association between folate status and success rate in assisted reproductive techniques. Although the importance of folate in the preconceptional phase is known, available data regarding the levels of folate in women who undergo infertility treatments are scarce. Referring to the threshold values generally used for the general population or for supplement users, the concentration of folate in the serum and erythrocytes of infertile women is adequate in the majority of the population with differences related to the geographic origin of the study populations. However, using the red blood cells folate threshold specifically indicated to prevent neural tube defects, the majority of available studies do not offer sufficient data to conclude on the real folate situation. As for the probability of success of ART treatments based on folate levels, our review did not reveal a significant effect.