Semen Analysis

A semen analysis (sperm test) is usually advised if a couple is having difficulty conceiving (becoming pregnant). The aim is to see if the semen and sperm made by the male partner are normal or not.

Note: the information below is a general guide only. The arrangements and the way tests are performed, may vary between different hospitals. Always follow the instructions given by your doctor or local hospital.

You will be given a specimen pot. Produce semen by masturbation into the pot. Do not use semen from a condom. Your doctor may ask you not to have sex for a certain amount of time before you produce the sample. Usually this means you should not have had sex for at least 48 hours beforehand (the length of time you are asked to abstain from having sex may vary - your hospital should give you information on this). However, no more than seven days should have gone by since last having sex. Ideally, you should deliver the sample to the laboratory within one hour of production. The pot which contains the sample should not be left out in the cold but should be kept warm - for example, in a pocket.

The semen sample is looked at with a microscope to count the number of sperm, look at their shape and to determine the percentage that are active (motile). The results can help detect whether there are any problems with the sperm likely to cause difficulties for a couple planning a pregnancy (infertility) . The results of the test generally fall into one of three categories:

  • Normal.
  • Definitely abnormal. This may mean there are very few or no sperm, or that the shape and size of sperm are not normal (this is referred to as sperm 'morphology').
  • Somewhere 'in between'. In these men, fertility is still possible. However, the more normal sperm there are and the higher the percentage that are active, the greater the chance of fertility.

If the test results show that the specimen was not normal, you may be asked to repeat the process. This is because sperm production can vary due to a number of different factors.

Sometimes, if the sperm count is borderline or slightly low, some of the following factors may be worth considering:

  • Was the sample ideal? See above on how to produce an ideal sample. It may be worth repeating to check this. Was it taken to the laboratory in time? Was it kept warm? Cooling the sample or a delay in getting it to the laboratory can alter the number of active sperm and give a false result.
  • High temperature of testicles (testes). Sperm are made in the testes which are in the scrotum. This is the body's way of keeping the testes slightly cooler than the rest of the body, which is best for making sperm. It is often advised for men who have a low sperm count to wear loose-fitting underpants and trousers and to avoid very hot baths, saunas, etc. This aims to keep your testes slightly cooler than the rest of your body, which is thought to be good for sperm production. It is not clear whether these measures improve a sperm count but they seem to be sensible.
  • Smoking can affect the sperm count. If you smoke, you should stop completely for optimum sperm production.
  • Alcohol. More than sixteen units per week (equivalent to about eight pints of normal strength beer or sixteen small glasses of wine) may interfere with optimum fertility.
  • Medicines and drugs. Most do not interfere with sperm production but some may do. These include: sulfasalazine, nitrofurantoin, tetracyclines, cimetidine, colchicine, allopurinol, some chemotherapy medicines, cannabis, cocaine and anabolic steroids. If you have a low sperm count, tell a doctor if you take any medicines or drugs regularly.
Original Author:
Dr Rachel Hoad-Robson
Current Version:
Peer Reviewer:
Dr John Cox
Document ID:
4348 (v39)
Last Checked:
12/08/2013
Next Review:
11/08/2016
The Information Standard - certified member