Is the volume of semen (seminal fluid) reduced after a vasectomy (male sterilization procedure)?

From the Guidelines

No, the amount of male ejaculate is not significantly reduced after a vasectomy. A vasectomy only blocks the vas deferens, which are the tubes that carry sperm from the testicles to the urethra. This procedure prevents sperm from mixing with seminal fluid during ejaculation, but sperm only makes up about 2-5% of the total ejaculate volume. The majority of semen volume comes from the seminal vesicles (60-70%) and prostate gland (20-30%), which continue to function normally after a vasectomy, as stated in the guidelines 1. Most men and their partners notice no difference in the amount of ejaculate after the procedure. This is because the production of seminal fluid continues unchanged, and the only difference is the absence of sperm in the ejaculate. The consistency, color, and other physical properties of the ejaculate typically remain the same as well.

Some key points to consider after a vasectomy include:

• The risk of pregnancy after vasectomy is approximately 1 in 2,000 for men who have post-vasectomy azoospermia or PVSA showing rare non-motile sperm (RNMS), as mentioned in the guidelines 1.
• Patients should refrain from ejaculation for approximately one week after vasectomy, and other contraceptive methods should be used until vasectomy success is confirmed by PVSA, as recommended in the guidelines 2.
• The decision to consider vasectomy a failure if >100,000 non-motile sperm/mL persist for six months or more after vasectomy should be based on clinical judgment that includes the trend of sperm counts, the patient’s preferences, and the patient’s tolerance for the risk of pregnancy, as stated in the guidelines 3.

Overall, the amount of male ejaculate is not significantly reduced after a vasectomy, and men can expect their sexual function and experience to remain largely unchanged after the procedure, with the only difference being the absence of sperm in the ejaculate, as supported by the guidelines 1, 2, 3.

From the Research

Effects of Vasectomy on Male Ejaculate

• The amount of male ejaculate after vasectomy has been studied in several research papers 4, 5, 6.
• A study published in 1979 found that the volume of semen in men decreased after vasectomy, but not significantly 6.
• The same study found that the viscosity and pH range of semen decreased significantly after vasectomy 6.
• Another study published in 2002 found that vasectomy had no significant effects on the quantitative parameters of stereology obtained from the testis, epididymis, prostate gland, and seminal vesicle in non-human primates 5.
• However, a study published in 2017 found that seminal vesicle fluid volume decreased significantly after ejaculation, and remained reduced for 2 days 7.
• The study also found that whole-prostate ADC values decreased significantly after ejaculation 7.

Mechanism of Vasectomy

• Vasectomy is a surgical procedure that disrupts and occludes the vas deferens, which delivers sperm from the testicles 4.
• The procedure provides permanent sterilization by interrupting sperm transport 4.
• The effects of vasectomy on the reproductive organs have been studied in several research papers 4, 5, 6.
• A study published in 2002 found that vasectomy had no significant effects on the structures of the reproductive organs in non-human primates 5.

Clinical Implications

• The effects of vasectomy on male ejaculate have important clinical implications 4, 6, 7.
• A study published in 2017 found that a 3-day period of abstinence from ejaculation is required to ensure maximal seminal vesicle distension before prostate MRI 7.
• The study also found that seminal vesicle sparing did not negatively affect margin status or 12-month biochemical recurrence in patients with prostate cancer 8.