Difficulty to conceive affects 1 in 15 couples.  It is defined as failure to achieve a pregnancy after one year of co-habitation and after having unprotected sexual intercourse for at least 2-3 times a week.

The man’s fertility generally relies on the quantity and quality of his sperm. When the number of sperm a man ejaculates is low or if the sperm are of a poor quality, it will be difficult, and sometimes impossible, for him to cause a pregnancy. Male infertility is commonly due to deficiencies in the semen, and semen analysis is used as a surrogate measure of male fecundity.

What is semen analysis?

Semen analysis is the laboratory assessment of freshly ejaculated semen. The number, shape and movement of sperm are evaluated under a microscopic examination.  When a couple is having medical investigations for infertility, testing of the male partner will usually include semen analysis. This is the most basic investigation to exclude male factor in problem of difficulty to conceive.

Where is semen analysis done?

Testing should be done at a specialised laboratory that uses the recommended World Health Organization (WHO) methodology; special equipment and expertise are needed to do an accurate semen analysis.

How is semen collected for testing?

Semen assessment is best done on a fresh semen sample (within one hour of being produced). A semen sample is best collected in a sterile specimen container by masturbation. If ejaculation by masturbation is difficult, semen may be collected by interrupted intercourse. Condom collection devices are available from specialised laboratories; ordinary condoms cannot be used because they usually contain agents that interfere with sperm motility (movement).

Semen is usually collected in a private room at the testing laboratory. When semen is collected at home the sample must be kept warm and taken to the laboratory very quickly – if possible within one hour.

It is important that none of the semen sample is lost. As sperm are mostly in the first part of the ejaculate, losing the first part of the ejaculate can falsely lower the sperm concentration. It is also important that the man does not ejaculate (period of abstinence) for at least two days but not longer than five days, before the sample is collected.

The quality of semen can fluctuate, even in fertile men. The doctor needs to be informed of any chronic medical conditions, fever, recent infection and medications, as all these can affect the sperm concentration.  In the presence of an abnormal result, a second semen assessment, at least six weeks apart, is needed to confirm these findings.

What is assessed in a semen analysis?

A number of different elements are tested and recorded in a semen analysis report.  The expected normal values include

  1.  Volume (ejaculate) must be more at least 1.5ml or more
  2. Concentration, at least 15million sperm per ml
  3. Motility, at least 40% within 60minutes after ejaculation
  4. Vitality (live sperm), at least 58% or more
  5. Morphology, at least 4% of normally shaped sperms
  6. pH, should be slightly alkaline with pH> 7.2
  7. White blood cells (inflammatory cells), must be less than 1 million per ml
  8. Presence of antibodies

Defects in the morphology (shape of the sperm heads or tails) can affect movement and the sperm’s ability to bind to and fertilize an egg.  By using the WHO methods, the morphology (shape) result is one of the markers that help to predict the ability to fertilize an egg. The limit for a normal morphology (ideally shaped sperm) is not less than four per cent of the total sperm.

Sperm antibodies occur in men when the immune system reacts to their own sperm.  These antibodies reduce fertility by binding the sperms to form clumps (agglutination) thus, decrease their motility and total number of motile sperm in the semen. The overall effect is a lower number of motile sperm available to fertilize the egg.


WHO Laboratory Manual for the Examination and Processing of Human Semen (5th Ed, WHO 2010)




Author: Dr Ng Soon Pheng

Dr. Ng Soon Pheng MD(USM), M.Med (O&G), Fellow Reprod Medicine (Singapore), AM (Mal) Dr. Ng Soon Pheng qualified from University Kebangsaan Malaysia (UKM), Malaysia. After obtaining his post graduate degree, Dr. Ng Soon Pheng continued his clinical fellowship training in the field of IVF in Singapore. He was also the recipient of Yayasan Sultan Iskandar (Johor) Scholarship for the fellowship stint. Dr. Ng Soon Pheng has more than 10 years of working experience in the field of Obstetrics and Gynaecology in the public and university hospital, with special interests in infertility. He was an Associate Professor with the Department of O&G in Universiti Kebangsaan Malaysia (UKM) specialising in infertility. Dr. Ng Soon Pheng is currently Consultant Obstetrician and Gynaecologist with special interests in infertility at Columbia Asia Hospital - Puchong.