Predictive value of normal sperm morphology: a structured literature review

Area of Science:

• Reproductive Medicine
• Andrology
• In Vitro Fertilization

Background:

• Male factor infertility is a significant challenge in assisted reproductive technologies.
• Sperm morphology, specifically the percentage of normal forms, has been investigated as a predictor of male fertility potential.
• Evaluating sperm morphology is crucial for optimizing in-vitro fertilization (IVF) outcomes.

Purpose of the Study:

• To conduct a structured literature review on the predictive value of normal sperm morphology in IVF.
• To establish the universal predictive value of normal sperm morphology as a semen parameter for male fertility.
• To analyze the relationship between normal sperm morphology thresholds and IVF success rates.

Main Methods:

• A systematic review of published literature from 1978-1996 was performed.
• Articles evaluating normal sperm morphology for predicting fertilization and pregnancy in IVF were identified.
• Data from 49 articles were tabulated, with 18 providing sufficient data for statistical analysis. Fifteen studies utilized strict criteria for morphology evaluation.

Main Results:

• Studies using 5% and 14% normal sperm morphology thresholds (strict criteria) showed positive predictive values for IVF success.
• Pregnancy prediction yielded positive values in 82% (5% threshold) and 75% (14% threshold) of studies.
• Aggregated data around the 5% threshold indicated higher fertilization (77.6% vs 59.3%) and pregnancy rates (26.0% vs 15.2%) for >4% normal morphology compared to <=4%.

Conclusions:

• Normal sperm morphology, particularly when evaluated using strict criteria, remains a valuable and cost-effective parameter in semen analysis for assessing male factor.
• Thresholds such as 5% and 14% normal morphology demonstrate predictive value for IVF success and pregnancy.
• Accurate evaluation of normal sperm morphology is integral to standard semen analysis for male fertility assessment.