Selection of fertilization strategies for different sperm parameters in vitro fertilization

Fertilization is a prerequisite for successful human reproduction. The choice of clinical fertilization strategy is crucial and directly affects clinical outcomes. This study analyzes the most appropriate assisted reproductive technology (ART) strategy based on sperm parameters.

Semen samples were divided into six groups based on semen progressive motility (PR) and semen density (SD): HMLD (high motility-low density) (PR ≥32% and sperm density <15×10⁶/mL, n=60), HMID (high motility-intermediate density) (PR ≥32% and 15×10⁶/mL ≤ SD <30×10⁶/mL, n=106), HMHD (high motility-high density) (PR ≥32% and SD ≥30×10⁶/mL, n=1,009), LMLD (low motility-low density) (PR <32% and SD <15×10⁶/mL, n=99), LMID (low motility-intermediate density) (PR <32% and 15×10⁶/mL ≤ SD <30×10⁶/mL, n=77), and LMHD (low motility-high density) (PR <32% and SD ≥30×10⁶/mL, n=164). We analyzed hyaluronic acid binding (HAB) assay and acrosin activity, along with fertilization, embryonic development, and pregnancy outcomes, to demonstrate the correlation of sperm parameters with fertilization function.

In the PR <32% groups, the rate of intracytoplasmic sperm injection (ICSI) treatment decreased with increasing sperm concentration. Specifically, approximately 10% of in vitro fertilization (IVF) treatment cycles required a rescue ICSI when sperm PR was <32% accompanied by SD ≥15×10⁶/mL and PR ≥32% accompanied by SD <30×10⁶/mL, which was significantly higher than HMHD group, P<0.001. Sperm acrosin activity and HAB ability were significantly higher in the groups with good sperm parameters, P<0.05.

The findings of this study suggest, fertilization ability of sperm is closely related to sperm motility and density. In clinical practice, IVF strategies should be refined based on male sperm parameters.