What is Semen?
💡 Semen is ejaculated fluid containing sperm + seminal plasma. Composition: ~65% seminal vesicle fluid, ~30% prostatic fluid, <5% sperm. Normal volume: ≥1.4 mL (WHO 2021); pH 7.2–8.0. Seminal plasma provides fructose (energy), zinc, prostaglandins. Semen analysis is the primary male fertility test.
Semen is the ejaculated fluid that transports sperm from the male reproductive tract. It comprises seminal plasma (from the seminal vesicles, prostate, and bulbourethral glands) plus spermatozoa. Sperm constitute less than 5% of semen volume; the plasma protects and nourishes them.
🇮🇳 India Context: Semen is widely assessed and treated across major Indian fertility centres including Chennai, Mumbai, Bangalore, Delhi, and Hyderabad.
What are the key characteristics of Semen?
- Composition: ~65% seminal vesicle secretions + ~30% prostatic fluid + ~5% epididymal fluid (containing sperm)
- Normal volume: ≥1.4 mL per ejaculate (WHO 2021); hypospermia: <1.5 mL; hyperspermia: >6 mL
- pH: 7.2–8.0 — alkaline, protecting sperm from the acidic vaginal environment (pH 3.5–4.5)
- Seminal vesicle fluid: contains fructose (primary sperm energy source), prostaglandins, and coagulating proteins
- Prostatic fluid: contains zinc, citric acid, PSA (liquefies the coagulated semen within 5–30 minutes of ejaculation)
- Sperm represent <5% of semen volume but carry the entire reproductive function
- Seminal plasma also contains antioxidants, immune-modulating factors, and signalling molecules affecting female immune tolerance
- Semen analysis assesses both seminal plasma parameters (volume, pH, liquefaction) and sperm parameters (count, motility, morphology)
How does Semen work?
Why does Semen matter in fertility?
Semen analysis is the single most important male fertility investigation and should be performed at the first fertility consultation — simultaneously with female workup, not sequentially. Understanding semen composition prevents clinical errors: low semen volume does not mean low sperm count (sperm are <5% of volume); a normal-looking ejaculate can contain severely abnormal sperm. In India, male factor investigation is frequently delayed due to cultural stigma — this avoidable delay costs couples months of inappropriate female-only treatment. Semen analysis (₹500–1,500 at accredited andrology labs) is the fastest, cheapest, and most clinically impactful test in fertility workup.
What are related terms to Semen?
Semen Analysis
Semen Analysis is the main test for evaluating male fertility. A semen sample is…
Sperm
Sperm (spermatozoa) are the male reproductive cells responsible for fertilising …
Sperm Count
Sperm count is the total number of sperm present in a complete ejaculate sample.…
Ejaculate Volume
Ejaculate volume is the total measured volume of semen produced in a single ejac…
Motility
Sperm motility is the ability of sperm to move effectively. WHO 2021 reference: …
FAQs about Semen
What is the difference between semen and sperm?
Sperm (spermatozoa) are the male reproductive cells — the gametes that fertilise the egg. Semen is the entire ejaculated fluid: seminal plasma (~95% by volume) + sperm (<5% by volume). Seminal plasma is produced by the seminal vesicles (~65%) and prostate (~30%). Sperm are the reproductive component; semen is their transport medium.
What is a normal semen analysis result?
WHO 2021 normal values: volume ≥1.4 mL; total sperm count ≥39M/ejaculate; concentration ≥16M/mL; total motility ≥42%; progressive motility ≥30%; morphology ≥4% normal forms; pH 7.2–8.0; liquefaction within 60 minutes. Two samples (2–7 days abstinence each) required for diagnosis — single sample results are not conclusive.
What does low semen volume mean?
Low volume (hypospermia: <1.5 mL) can indicate: retrograde ejaculation (sperm enters bladder — check post-ejaculate urine), ejaculatory duct obstruction, congenital bilateral absence of vas deferens (CBAVD — associated with CFTR mutation, also causes absent fructose and low pH), androgen deficiency, or incomplete collection. Not the same as low sperm count.
How long does semen analysis take?
Semen analysis results are available within 1–4 hours of submission at most andrology labs — the sample must be processed within 1 hour of ejaculation. A detailed analysis including morphology (Kruger strict criteria) may take 24–48 hours. In India, comprehensive semen analysis costs ₹500–1,500 at accredited andrology laboratories.
Does semen quality affect IVF success?
Yes — significantly. Severely abnormal semen parameters reduce fertilisation rates in conventional IVF (ICSI bypasses this). High sperm DNA fragmentation (DFI >25%) impairs embryo development and raises miscarriage risk even when standard semen parameters are normal. Sperm quality is one of three primary determinants of IVF success (along with egg quality and endometrial receptivity).
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