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You notice that the tabetic has the power of holding water for an indefinite period. He is also impotent—in fact, two excellent properties to possess for a quiet day on the river.

Dr Dunlop, Teaching at Charing Cross Hospital, 1913


Subfertility is defined as the absence of conception after a period of 12 months of normal unprotected sexual intercourse.1 Interestingly, normal fertility is defined as ‘achieving a pregnancy within 2 years of regular sexual intercourse’ and applies to about 95% of couples.2 The inability to conceive can be a very distressing and emotional problem for a couple, who need considerable care, empathy and relatively rapid investigation of their problem. In assessing a couple with the problem of subfertility (this term is a preferable way of describing the condition to the patients), it is appropriate to involve both partners in the consultation. In determining the cause of the subfertility, three basic fertility parameters should be investigated.3


  • The right number of sperm have to be placed in the right place at the right time.

  • The woman must be ovulating.

  • The tubes must be patent and the pelvis sufficiently healthy to enable fertilisation and implantation.


As a general rule, the major factors limiting fertility are one-third female, one-third male and one-third combined male and female.4


In addition, there are couples who fulfil the three primary fertility factors (egg, sperm and tubes) but do not conceive. This is known as unexplained (idiopathic) subfertility.


Key facts and checkpoints

  • Infertility affects about 10–15% (1 in 7) of all cohabitating couples.4

  • This incidence increases with age.

  • After the age of 32 fertility decreases by 1.5% per year.

  • About 15% of couples who do not use contraception fail to achieve a pregnancy within 12 months.5

  • More than 5% remain unsuccessful after 2 years.5

  • About 50% of couples will seek medical assistance.5

  • The main factors to be assessed are ovulation, tubal patency and semen analysis.

  • About 40% of couples have an identifiable male factor. Treatable causes are rare.

  • The main identifiable causes of male infertility are failure of spermatogenesis, failure of sperm delivery and sperm autoimmunity.4

  • The technique of intracytoplasmic sperm injection (ICSI) has revolutionised the treatment of male infertility.

  • Female factors account for about 40%: tubal problems account for about half and ovulatory disorders for roughly the other half.4 Polycystic ovarian syndrome (PCOS) is the most common cause of ovulatory dysfunction.6 Treatable factors are the big three causes—tube disease, anovulation and endometriosis.

  • The initial investigation for the man is semen analysis on two occasions. The initial investigation for the woman is a basal body temperature chart, associated with midluteal progesterone measurement.

  • In about 20% of couples, no apparent cause is identified (idiopathic).4

  • Sperm autoantibodies (IgG and IgA) can be detected in the blood and/or seminal ...

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