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Clinical Review ABC of subfertility

Male subfertility

BMJ 2003; 327 doi: (Published 18 September 2003) Cite this as: BMJ 2003;327:669

This article has a correction. Please see:

  1. Anthony Hirsh, consultant to the andrology clinic, honorary senior lecturer
  1. Whipps Cross Hospital, London, King's, Guy's, and St Thomas's School of Medicine, London


    Abnormal semen quality or sexual dysfunction are contributing factors in about half of subfertile couples. As natural pregnancy is substantially reduced in these cases, the man should be assessed by an appropriately trained gynaecologist in a reproductive medicine clinic, or by a clinical andrologist. Subfertile men often defer consultations because they perceive subfertility as a threat to their masculinity. Consultations should help them to distinguish between fertility and virility, which may ease their anxiety. However, achievement of a wanted pregnancy is more likely to restore manly feelings.

    View this table:

    Semen analysis terminology

    Causes of male subfertility

    Subfertility affects one in 20 men. Idiopathic oligoasthenoteratozoospermia is the commonest cause of male subfertility. Although sexual function is normal, there is a reduced count of mainly dysfunctional spermatozoa. Reduced fertilising capacity is related to raised concentrations of reactive oxygen species in semen, which may damage the cell membrane. Abnormal sperm morphology–an indicator of deranged sperm production or maturation–is also associated with reduced fertilising capacity. Less common types of male subfertility are caused by testicular or genital tract infection, disease, or abnormalities. Systemic disease, external factors (such as drugs, lifestyle, etc), or combinations of these also result in male subfertility. Male subfertility is rarely caused by endocrine deficiency.

    Sperm morphology is related to the fertilising capacity by in vitro fertilisation. (A=normal sperm head; B=abnormal head; C=globozoospermia–a rare syndrome in which all sperm heads lack acrosome caps and cannot fertilise)

    Falling sperm counts have not affected global fertility, although the effect of increased oestrogenic compounds in drinking water is of concern because the incidence of cryptorchidism and testicular cancer is increasing.

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    Normal seminal fluid analysis (World Health Organization, 2002)

    Clinical assessment

    History taking should include frequency of coitus, erectile function, ejaculation, scrotal disorders or surgery, urinary symptoms, past illnesses, lifestyle factors, and any drugs taken. Physical examination should seek signs of hypogonadism (small …

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