ICSI versus Conventional IVF in Women Aged 40 Years or More and Unexplained Infertility: A Retrospective Evaluation of 685 Cycles with Propensity Score Model

This study compared the cumulative live birth rates following Intracytoplasmic sperm injection (ICSI) versus conventional in vitro fertilization (cIVF) in women aged 40 years or more and unexplained infertility. A cohort of 685 women undergoing either autologous conventional IVF or ICSI was retrospectively analyzed. The effects of conventional IVF or ICSI procedure on cumulative pregnancy and live birth rates were evaluated in univariate and in multivariable analysis. In order to reduce potential differences between women undergoing either IVF or ICSI and to obtain unbiased estimation of the treatment effect, propensity score was estimated. ICSI was performed in 307 couples (ICSI group), whereas cIVF was performed in 297 couples (cIVF group), resulting in 45 and 43 live deliveries, respectively. No differences were observed in morphological embryo quality, in the number of cleavage stage embryos, in the number of transferred embryos, and in the number of vitrified embryos. As for the clinical outcome, no differences were observed in pregnancy rate, cumulative pregnancy rate, live birth rate, cumulative live birth rate, and abortion rate. The present results suggest that ICSI is not associated with increased likelihood of a live birth for unexplained, non-male factor infertility, in women aged 40 years or more.