Intracytoplasmic morphologically selected sperm injection versus intracytoplasmic sperm injection: a step toward a clinical algorithm

ObjectiveTo study the advantage of intracytoplasmic morphologically selected sperm injection (IMSI) versus intracytoplasmic sperm injection (ICSI) in the first artificial reproductive technology (ART) cycle and in consecutive cycles.DesignA cohort study.SettingSingle outpatient fertility center.Patient(s)Couples presenting with male factor infertility, requiring ovum micromanipulation.Intervention(s)The ICSI or IMSI was performed according to the couple's choice.Main Outcome Measure(s)Clinical intrauterine pregnancies and deliveries.Result(s)A total of 1,891 IVF-ICSI cycles and 577 IVF-IMSI cycles were included. In the first IVF treatment, pregnancy rates (PRs) were 46% and 47%, respectively, and delivery rates were 23% versus 30%, respectively. In the second cycle to follow a failed ICSI, PRs and delivery rates were significantly higher for patients who chose to shift to the IMSI technique compared with patients who chose to go through a second IVF-ICSI cycle (56% vs. 38% PRs and 28% vs. 18% delivery rates, respectively). In the following cycles a significant difference was demonstrated in both PR and delivery rates in favor of patients shifting between treatments. In a multivariate analysis an approximate threefold increased chance existed for both pregnancy and delivery only in the case of couples failing an ICSI attempt who shifted to IMSI.Conclusion(s)Our present experience supports refraining from repeated IMSI cycles. In light of improved PRs and delivery rates, we recommend promoting the IMSI method for couples who failed ICSI cycle, once or more.