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Hematospermia.com

After a procedure

Blood in semen after a vasectomy

Common, usually harmless, and typically gone within a few weeks.

By the Hematospermia.com editorial teamUpdated Medical review pending
Illustration of a man resting in a recliner at home while a nurse talks him through recovery instructions.

Educational information only, not a diagnosis. Know when to get help.

On this page
  1. Why it happens
  2. How long can it last?
  3. When to call your surgeon
  4. Can I keep having sex or ejaculating?
  5. Sources

Seeing blood in your semen in the days or weeks after a vasectomy is a known, usually harmless side effect of the procedure. NHS and Cleveland Clinic both list vasectomy as a common cause [NHS] [Cleveland Clinic].

Why it happens

A vasectomy cuts or seals the vas deferens, the tubes that carry sperm from each testicle. Minor bleeding and bruising from the procedure can mix into the ejaculate as the area heals [Cleveland Clinic].

Timeline showing blood in semen is often seen for up to about four weeks after a prostate biopsy or vasectomy, with advice to contact a clinician if it persists beyond three to four weeks.
What to expect after a procedure. Based on Cleveland Clinic, NICE CKS and Mayo Clinic guidance.

How long can it last?

Cleveland Clinic notes that you may see blood in your semen for more than a week after a vasectomy [Cleveland Clinic]. It usually fades from red to brown as old blood clears. As a general rule, Mayo Clinic advises contacting a professional if blood in semen lasts longer than 3 to 4 weeks or keeps returning [Mayo Clinic]. Your surgeon's own aftercare instructions come first.

When to call your surgeon

  • Blood in semen that's still there after 3–4 weeks, or getting heavier rather than lighter [Mayo].
  • Fever, increasing pain, redness, or pus from the wound, which can be signs of infection.
  • A scrotum that is swelling quickly or very painful, which can signal bleeding under the skin (hematoma).
  • Blood in your urine, or pain when peeing [Mayo].
Important: you are not sterile yet

A vasectomy doesn't work straight away. Sperm can remain in the tubes for a while, so you need to keep using contraception until a semen test confirms there are no sperm [NHS]. Blood in the semen does not mean the vasectomy has failed, and a clear sample doesn't mean you're sterile yet.

Can I keep having sex or ejaculating?

Follow your surgeon's instructions on when to resume. Seeing a little blood once you do is common in the healing period and isn't by itself a reason to stop, unless it is painful or heavy. Using a condom avoids alarming a partner and also protects against infection.

Sources

  1. Blood in semen NHS, reviewed Sep 2025
  2. Blood in Semen (Hematospermia) Cleveland Clinic Health Library, reviewed Jan 2024
  3. Blood in semen: when to see a doctor Mayo Clinic
  4. Vasectomy (male sterilisation) NHS

We link to primary medical sources so you can check our work. See the editorial policy and the full reference list.