Title: chromosomal abnormalities. Study design, size and duration:Design: Retrospective

Title: Reproductive Outcomes In Patients With Severe Oligospermia Undergoing Intracytoplasmic Sperm Injection Using Testicular Versus Ejaculated Sperms  Study question:  To compare intracytoplasmic sperm injection (ICSI) outcome in patients with severe oligospermia using testicular versus ejaculated sperms.Summary answer:  In patients with severe oligospermia, when both sources of spermatozoa are available (i.e. ejaculate or testicular) for the ICSI procedure, TESE should be considered as it offers higher pregnancy rates. What is known already:  In infertile men with severe oligospermia (sperm concentration <5 million/mL) undergoing ICSI  the choice between using repeatedly ejaculated sperm or recommending use of testicular sperm remains controversial.Testicular sperm have shown lower levels of DNA damage compared with ejaculated spermatozoa from the same individuals, however testicular sperm exhibit higher rates of chromosomal abnormalities. Study design, size and duration:Design: Retrospective cohort study.Size and duration: Patients with severe oligospermia who underwent ICSI cycles with either testicular or ejaculated sperm between January 2014 and December 2016 were included in this study.205 couples met the study criteria after exclusion of cycles with mixed sperm sources. Participant /Materials, setting and methods:Setting: private center in Alexandria, Egypt.Patients were divided into 2 subgroups according to the source of sperm cells used in intracytoplasmic sperm injection (ICSI) cycle; (Group A) included 104 patients in which ejaculated sperms were obtained  while (Group B) included 101 patients where  fresh testicular sperms wereextracted (TESE) .The medical records of the included couples were reviewed and tabulated regarding demographic data, reproductive history, hormonal profiles and different semen parameters.After micro injection; fertilization rate, cleavage rates, embryo quality, implantation and pregnancy rates were evaluated and compared in both groups.     Main results and role of chance:There was no significant difference in the fertilization ratebetween the two subgroups (group A 67.93%, group B 68.01%, p=0.960), however the cleavage rate of day 2embryos was significantly higher when testicular sperm cells were used (47.37% vs 42.77%, p=0.024*).Implantation rate was slightly lower in group A compared to group B but without statistical significance (25.23% and 29.77% respectively, p=0.292).There were no statistically significant differences between both subgroups regarding number and quality of day 3 and day 5 embryos. Pregnancy rate was significantly higher in group B where testicular sperm cells were used (54.45% vs 40.38, p=0.044*).Limitations, reasons for caution:Prospective randomized studies involving larger number of cases are needed to establish whether TESE should be performed as a routine step in infertile males with severe oligospermia or should it be limited to cases with previous ICSI failure.TESE remains a surgical intervention which may not preferred by some patients due to possible associated risk.Wider implication of the findings:Sperm source can lead to better ICSI outcome in this certain group of patients; such finding may extend to include infertile males with abnormal DNA fragmentation testing. Key Words: Infertility, severe oligospermia,Intracytoplasmic sperm injection, Testicular sperm extraction (TESE),