This study intends to carry out a prospective, randomized, double blind and controlled study
to compare the influence of Atosiban and placebo on uterine contraction frequency,
endometrial blood flow perfusion, oxytocin and serum concentration of PGF2α, embryo
implantation rate and clinical pregnancy rate on the RIF population after fresh embryo
transfer, so as to further clarify the curative effect of Atosiban in the treatment of RIF
and provide evidence-based basis for Atosiban for application in RIF population.