Effects of periconceptional folic acid supplementation on incidences of twin pregnancy：a Meta analysis

Abstract:

Objective：To use Meta analysis to assess the effects of folic acid supplementation before and during early pregnancy on twin pregnancy. Methods：Literatures associated with periconceptional folic acid supplementation between 1966 and 2012 were col－lected systematically from PubMed/Medline，EMBASE，OVID，Cochrane Central Register of Clinical Trials，Google scholarism，CNKI，VIP，Wanfang databases，then were screened according to the pre-established inclusion and exclusion standards. Quality was evaluat－ed strictly. Data were extracted and Meta analysis was conducted using RevMan 5.2.1 software. Results：Three randomized controlled trials（RCTs） were included. Differences in twin pregnancy incidences（RR=1.40，95%CI=0.93 to 2.11），dizygotic incidences（RR=1.27，95%CI=0.61 to 2.67） and monozygotic incidences（RR=0.91，95%CI=0.68 to 1.21） were of no statistically significant between group with folic acid supplementation before and during early pregnancy and control group. Conclusion：Folic acid supplementation before and during early pregnancy can not increase incidences of twin pregnancy.