Atosiban and Pregnancy Outcomes Following In Vitro Fertilization Treatment for Infertile Women Requiring One, Two, or More Embryo Transfer Cycles: A Longitudinal Cohort Study

We assessed the effect of atosiban on pregnancy outcomes following in vitro fertilization (IVF) treatment among infertile women requiring different numbers of embryo transfer (ET) cycles (i.e., one, two, and more than two ET cycles). A longitudinal cohort study was conducted by utilizing the data from the Assisted Reproductive Technology Center in a university tertiary hospital during 2007–2017. Patients receiving IVF treatment with at least one ET cycle were included. Pregnancy outcomes following IVF treatment, including biochemical, clinical, and ongoing pregnancies, were investigated. The association between atosiban and IVF pregnancy was assessed using logistic generalized estimating equation models, with adjustment for time-varying clinical characteristics (e.g., maternal age) across multiple ET cycles for an individual. 403 women with 838 ET cycles were included, where 165 patients required one ET cycle, 133 patients required two ET cycles (a total of 266 ET cycles), and 105 patients required more than two ET cycles (a total of 407 ET cycles). Atosiban use was not significantly associated with pregnancy outcomes among all study infertile women undergoing IVF treatment. However, the results for women requiring more than two ET cycles showed significantly increased pregnancy rates associated with atosiban use (i.e., odds ratios [95% confidence interval] of 4.40 [1.52, 12.73] and 2.85 [1.45, 5.60] for clinical and ongoing pregnancies, respectively). This association was not observed for the women requiring only one or two ET cycles. Atosiban is a potential treatment for enhancing IVF pregnancy, especially among infertile women requiring more than two ET cycles.