Preparation
Abstinence before a semen analysis
Why laboratories ask for 2 to 7 days without ejaculation before a semen analysis, and why you should use the interval on your appointment letter.
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Short answer
For a WHO-style semen analysis, the usual abstinence period is 2 to 7 days. That is the interval since the last ejaculation, not since the last time you had sex with a partner if you have ejaculated another way. Your laboratory’s requested interval is the one that matters, because the reference limits assume a defined collection method.
Key takeaways
- Shorter abstinence tends to lower volume and total sperm number.
- Longer abstinence can raise count while motility and the condition of the sperm may worsen.
- The reference limits are not valid for a random sample collected outside the method.
- Do not “save up” for weeks. That is not how the reference values were derived.
Why the interval changes the numbers
After ejaculation, sperm and seminal fluid build back up over the following days. A sample produced the same day will often have a lower volume and a lower total sperm number. A sample produced after a long gap can look more concentrated while containing a higher share of sperm that do not move well. Comparing either sample with the WHO 5th-centile limits, without knowing the abstinence period, is a weak comparison.
What to do in practice
- Read the appointment letter. If it names a number of days, use that.
- If it only says 2 to 7 days, pick a day inside that range and write the actual number of days on the form.
- Count ejaculation, including masturbation, not only intercourse.
- If you miscount, still attend if the laboratory will take the sample, and record the true interval. Hiding it makes the report harder to interpret.
NICE’s advice to repeat an abnormal test after about three months is a separate interval. It allows a new wave of sperm production. It is not an instruction to abstain for three months.
This is about the test, not a conception rule
Abstinence advice for a laboratory sample is not a rule for how often to have sex when trying to conceive. Those are different questions. Do not use a long abstinence period as a fertility strategy because a single test looked better after one.
Related
Sources
- WHO laboratory manual for the examination and processing of human semen, 6th edition — World Health Organization, 2021
- Fertility problems: assessment and treatment (NG257) — NICE, 2026
How this page was prepared
Drafted with automated research assistance and checked against the cited primary sources. A named clinician has not reviewed this page. Medical review is pending. Changes to reference values are not published automatically.