Semen pH

Definition - What does Semen pH mean?

Semen pH is an indicator of acidity or alkalinity of the seminal fluid. Under normal conditions, semen is slightly alkaline with a pH ranging from 7.2-8.0 according to WHO guidelines. Having the optimum pH level in semen is important for sperm cells to maintain its mobility and the alkalinity helps to neutralize the acidic vaginal environment. If the semen pH is abnormal, either acidic or too alkaline, it can interfere with the sperm quality and cause infertility.

FertilitySmarts explains Semen pH

pH is a measurement of hydrogen ions in a solution. The pH value indicates if the solution is acidic or basic. pH can range from 0-14, 0 being the strongest acid and 14 the strongest base. Pure water is considered neutral and has a pH of 7.

Semen is produced mainly by the seminal vesicles, which are 2 glands located behind the bladder and the prostate. Secretions from the seminal vesicles are basic while prostrate secretions are slightly acidic, so semen formed by mixing of these fluids remain slightly alkaline and provides the optimum environment for sperm.

Maintaining this acid-base balance in semen is important for keeping the sperm healthy and protected from the outside environment. If the pH of the semen is too acidic or too alkaline, it can kill sperms or impair their ability to move and fertilize the egg.

Vaginal fluid is acidic with a pH ranging from 3.5-4.5. This is largely due to lactic acid produced by harmless bacteria growing in the vagina. The acidic pH prevents disease-causing bacteria and fungi from growing and keeps the vagina healthy. However, this environment is not ideal for sperm, therefore, sperm relies on the ability of the semen (along with cervical mucus) to neutralize the acidity and achieve a pH that is close to neutral, so sperm can effectively swim across the vagina and cervix to the uterus to fertilize the egg.

Abnormalities in semen production in the male reproductive tract such as infection or blockage of seminal vesicles can cause suboptimal pH levels in semen. This ultimately results in male subfertility.

If male subfertility is diagnosed or suspected, a semen analysis is indicated. Semen pH is routinely tested during a semen analysis, so abnormalities in pH can be detected.

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