Semen pH in patients with normal versus abnormal sperm characteristics

Area of Science:

• Andrology
• Reproductive Medicine
• Clinical Chemistry

Background:

• The World Health Organization (WHO) manual specifies a normal semen pH range of 7.2 to 8.0.
• Clinical observations suggest semen pH values in certain patient populations may exceed this established range.

Purpose of the Study:

• To investigate and confirm whether semen pH values in a large patient cohort consistently fall outside the currently accepted WHO reference range.
• To compare semen pH in patients with normal and abnormal sperm parameters.

Main Methods:

• Retrospective review of over 1100 semen records from January 1994 to December 1998.
• Analysis included semen pH, sperm concentration, and motility.
• Semen pH was also assessed in a subgroup undergoing sperm preparation for intrauterine insemination (IUI) with documented pregnancies.
• Statistical analysis employed histograms and the Mann-Whitney test.

Main Results:

• The mean semen pH for all 1199 patients was 8.2 ± 0.3, with a range of 7.3 to 9.5.
• 32% of samples exhibited a pH below 8.0.
• No significant difference in mean semen pH (8.2) was observed between patients with normal (n=602) and abnormal (n=597) sperm parameters.
• In a subgroup (n=19) with documented pregnancies post-IUI, the mean semen pH was 8.3 ± 0.3 (range 7.9-8.7).

Conclusions:

• The findings challenge the established WHO reference range for semen pH (7.2–8.0).
• Observed mean semen pH values, including those from patients with normal sperm parameters, consistently exceed the WHO guidelines.
• This suggests a potential need to re-evaluate the standard reference range for semen pH in clinical practice.