Does physiological sperm selection improve live birth rates in isolated teratozoospermia? A single-center retrospective cohort study.

research questionDoes physiological intracytoplasmic sperm injection (PICSI) improve live birth outcomes compared with conventional ICSI (CICSI) in couples with isolated teratozoospermia?

designThis single-center retrospective cohort study included couples with isolated teratozoospermia, defined according to WHO (World Health Organization) 2021 criteria in the presence of normal sperm concentration and motility but abnormal sperm morphology (< 4% morphologically normal forms assessed by Kruger strict criteria), who underwent ICSI using fresh ejaculated sperm at a tertiary IVF center between 2023 and 2024. Sperm selection was performed using hyaluronan-based PICSI (n = 98) or CICSI (n = 192). Women with normal/good ovarian reserve were included in the study, whereas women with low ovarian reserve or expected poor ovarian response, as defined by the POSEIDON (Patient-Oriented Strategies Encompassing Individualized Oocyte Number) criteria, were excluded. Cycles using all forms of surgical sperm retrieval and those involving partial or complete globozoospermia sperm morphology were excluded. Preimplantation genetic testing for aneuploidy (PGT-A) was not performed in the study cohort. All embryo transfers were performed as frozen Day-5 blastocyst transfers. The primary outcome was live birth. Multivariable logistic regression was used to identify independent predictors of live birth.

resultsBaseline female and male characteristics, stimulation parameters, and semen variables were comparable between groups. The CICSI group had significantly more retrieved oocytes, MII oocytes, and total blastocysts; however, the number of ≥ 3BB blastocysts did not differ. Univariate analysis showed no significant differences in biochemical pregnancy, clinical pregnancy, miscarriage, or live birth rates between groups. Live birth rates per embryo transfer were comparable between the PICSI and the CICSI groups (56.6% vs 56.5%, respectively; p = 0.987). Despite these comparable unadjusted live birth rates, multivariable logistic regression demonstrated that PICSI was independently associated with a higher likelihood of live birth (adjusted OR 2.736; 95% CI 1.147-6.531; p = 0.023), whereas no other variable was independently predictive. Singleton birth weight was significantly higher in the PICSI group (3321 ± 475 g versus 3132 ± 572 g; p = 0.036).

conclusionsPICSI was independently associated with improved live birth outcomes in couples with isolated teratozoospermia, suggesting that sperm functional quality plays a clinically relevant role beyond conventional morphological assessment. These findings support the potential value of PICSI as a targeted sperm selection strategy in this population, although prospective validation is warranted.