What happens if my seminal vesicles or prostate produce less fluid, affecting my ejaculated volume?

Reduced Seminal Vesicle and Prostate Fluid Production: Impact on Fertility

Yes, your testicles can still produce sperm normally even when your seminal vesicles or prostate produce less fluid, resulting in lower ejaculate volume—the key issue is whether the reduced volume affects sperm transport and fertility, not sperm production itself. 1

Understanding the Distinction Between Fluid Volume and Sperm Production

The seminal vesicles and prostate contribute approximately 60-70% and 20-30% of ejaculate volume respectively, while the testicles and epididymis contribute only about 5% of total volume but contain all the sperm. 2 When these accessory glands produce less fluid, your ejaculate volume drops below the normal threshold of 1.4 mL, but testicular sperm production remains completely independent of this process. 1

Critical Clinical Implications

• Low ejaculate volume (<1.4 mL) with normal testicular size and normal FSH levels typically indicates obstruction rather than sperm production failure, meaning your testicles are functioning normally but the fluid pathway is compromised. 1, 3

• The fertility impact depends on the underlying cause: if reduced volume is due to ejaculatory duct obstruction (EDO), approximately 50% of patients show improved semen parameters after surgical correction, with 25% achieving pregnancy naturally. 4

• Acidic semen (pH <7.0) combined with low volume strongly suggests either ejaculatory duct obstruction or congenital bilateral absence of vas deferens (CBAVD), both of which can trap normally-produced sperm. 1, 3

When to Suspect Obstruction vs. Production Problems

Signs Your Testicles Are Still Producing Sperm Normally

• Normal testicular size and consistency on examination (atrophic testes suggest production failure, not obstruction). 3, 5

• Normal or low-normal FSH levels (<7.6 IU/L)—elevated FSH (>7.6 IU/L) indicates primary testicular failure. 3, 5

• Palpable vas deferens bilaterally (absence suggests CBAVD where sperm are produced but cannot exit). 3

• Normal testosterone levels (low testosterone with low FSH suggests hypogonadotropic hypogonadism affecting sperm production). 3

Red Flags for Actual Sperm Production Problems

• Atrophic (small, soft) testicles on examination indicate spermatogenic failure, not just fluid reduction. 5

• Elevated FSH (>7.6 IU/L) suggests primary testicular dysfunction. 5

• Non-homogeneous testicular architecture on ultrasound represents impaired spermatogenesis. 5

Diagnostic Algorithm for Low Ejaculate Volume

When ejaculate volume is <1.4 mL, clinicians should be suspicious of distal male genital tract obstruction. 1

Essential Initial Workup

• Check semen pH: acidic semen (pH <7.0) with low volume strongly suggests EDO or CBAVD. 1, 3

• Measure serum testosterone and FSH: normal testosterone with normal/low FSH and low volume points to obstruction; elevated FSH suggests testicular failure. 3

• Perform post-ejaculatory urinalysis when volume <1 mL (except in bilateral vasal agenesis or hypogonadism) to diagnose retrograde ejaculation. 3

• Palpate for vas deferens bilaterally: CBAVD can be diagnosed by physical examination alone. 3

Advanced Imaging (Only When Indicated)

• TRUS or pelvic MRI should be reserved for suspected EDO when semen is acidic, volume <1.4 mL, with azoospermia or severe oligospermia with very low motility, normal testosterone, and palpable vas deferens. 1, 3

• Do not perform TRUS or pelvic MRI as part of initial evaluation—this is a common pitfall that leads to unnecessary testing. 1, 3

Treatment Implications Based on Cause

If Obstruction Is Confirmed (Testicles Still Producing Sperm)

• Transurethral resection of ejaculatory ducts (TURED) is definitive treatment for confirmed EDO on TRUS or MRI showing dilated seminal vesicles and ejaculatory ducts. 3, 4

• For CBAVD, no medical or surgical treatment restores ejaculatory volume—proceed directly to sperm retrieval (TESE/MESA) with ICSI for fertility, as the testicles are producing sperm that simply cannot exit. 3

• CFTR gene testing for the female partner is mandatory before proceeding with assisted reproduction in CBAVD cases. 3

If Testicular Production Is Actually Impaired

• Varicocelectomy improves semen parameters for palpable varicoceles with abnormal semen analysis, and may restore sperm in ejaculate for men with azoospermia, particularly those with hypospermatogenesis on histology. 3

• Treatment of non-palpable (subclinical) varicoceles should not be performed, as this does not improve semen parameters or fertility rates. 1, 3

Common Pitfalls to Avoid

• Do not assume low volume automatically means poor sperm production—the two are anatomically and functionally separate processes. 2

• Do not hunt for subclinical varicoceles with ultrasound—only palpable varicoceles benefit from treatment. 1, 3

• Do not delay genetic testing (karyotype and Y-chromosome microdeletion analysis) for azoospermia or severe oligospermia (<5 million/mL)—results impact counseling and treatment decisions before assisted reproduction. 3, 5

• Certain medications reduce seminal volume without affecting sperm production: finasteride 5 mg/day is associated with reduced semen volume, though 1 mg/day data are inconclusive. 1

Bottom Line for Fertility

The critical question is not whether your testicles can still produce sperm (they usually can), but whether the reduced fluid volume is preventing sperm from reaching the ejaculate or impairing sperm transport in the female reproductive tract. 6, 2 Adequate semen volume is required to transport sperm into the female reproductive tract for fertilization, so even with normal sperm production, severely reduced volume can impair fertility. 6