Meta-Analysis On The In Vitro Fertilization And Breast Cancer Risk

Background:The effects of controlled ovarian hyperstimulation(COH)for IVF in terms of breast cancer risk remain controversial.Objective:To investigate the association between IVF and breast cancer risk by conducting a meta-analysis of previous cohort studies.Methods:Eligible studies up to 30 December 2018 based on CNKI,VIP Journal Integration Platform,WANFANG Data,PubMed,OVID,Web of Science,Embase and The Cochrane Library,pooled effect estimates for relative risk(RR)and its 95%CI were calculated with DerSimonian and Laird random-effects model,for the investigations using the general population or infertile women as a reference group.Results:Ten cohort studies were synthesized,yielding a total cohort size of3,030,952 women among whom 27,268 incident breast cancer cases occurred,encompassing 1573 incident breast cancer cases among women exposed to IVF.Overall,no statistically significant association between IVF and breast cancer risk was observed in the group of studies(RR=1.01,95%CI:0.90~1.13)?The age of first time IVF>35 years(RR=1.15,95%CI:0.96~1.37)and multi-cycle IVF(RR=1.17,95%CI:0.79~1.75)may increased the risk of breast cancer.There was obvious heterogeneity between the included studies(P=0.042 for heterogeneity,I~2=48.3%).Conclusions:At present,IVF does not seem to increased breast cancer risk.Due to the obvious heterogeneity and null results in over all analysis and most of subgroup analyses,longer follow-up periods,larger informative data sets and adjustment for various confounders are needed before conclusive statements for the safety of the procedure are reached.