Variation of semen measures within normal men.

Area of Science:

• Reproductive biology
• Andrology
• Clinical biochemistry

Background:

• Semen analysis is crucial for male fertility assessment.
• Understanding variability in semen parameters is essential for accurate interpretation.
• Previous studies have not fully characterized short-term variations in multiple semen measures.

Purpose of the Study:

• To quantify within-subject variation in key semen parameters over a 6-month period.
• To determine the impact of abstinence duration on semen measures.
• To establish guidelines for optimal semen specimen collection for reliable fertility assessment.

Main Methods:

• Bimonthly semen analyses were performed on 15 healthy men over 6 months.
• Sperm count, morphology, motility, and semen volume were assessed.
• Statistical analysis included coefficients of variation and correlation analyses.

Main Results:

• Considerable within-subject variation was observed for sperm count, morphology, motility, and semen volume.
• Each additional day of sexual abstinence increased semen volume by 0.62 ml, sperm count by 17.6 x 10^6/ml, and motility by 1.2%.
• Sperm count and semen volume showed a positive within-subject correlation.

Conclusions:

• Semen parameters exhibit substantial day-to-day variability.
• A reliable semen profile can be established using three specimens collected within a two-week interval.
• These findings provide practical guidance for clinical and research applications of semen analysis.