Inability to conceive after at least a year of regular sexual intercourse without the use of contraceptives, can be due to causes that lie either in the man or the woman or both. Identification of the underlying causation is the key to successful treatment, but is extremely difficult. It often occurs in women who have a history of conceiving and then losing the baby before the foetus is old enough to support itself outside the womb. Infertility can be either temporary or, in a small percentage of cases, permanent.

Male Infertility

• Sperm count. The commonest cause in men is no sperm or a low sperm count. This may be caused by numerous factors including an infection after puberty which was accompanied by a high fever, unrepaired undescended testicles, taking certain drugs, trauma to the testicles, or exposure to large amounts of X-ray. For the most part however, a low sperm count tends to be related to more easily reversible conditions. A long illness or a chronic infection may lower general health, as could poor diet, strenuous physical exercise, lack of exercise, too much smoking and drinking, over-weight, overwork, tension and fatigue. A common reason for a low sperm count is abnormal temperature regulation in the testicles, which function at a temperature slightly lower than the rest of the body.
  
• Low sperm motility. This makes them unable to travel from the vagina, through the fallopian tubes to fertilize the ovum. This tends to be related to some of the above factors, and may also be due to enlargement of the prostate gland, as well as an imbalance of male hormones in the body. The vessels along which the sperm travel in men could be blocked by an inflammatory or infectious process or by varicosity in the area.

• Endocrine problems. Difficulties of the pituitary, thyroid or adrenal glands, which together regulate the menstrual cycle, may cause a failure of ovulation. To establish whether you are ovulating at regular intervals you can keep a record of your body temperature using a chart and a sensitive thermometer. Before ovulation, when there is normal secretion of oestrogen, the basic temperature on waking will be a little below normal, 97 or 97.8deg.F, 36deg.C. After ovulation it should rise by half or one degree and stays the same for the next two weeks.
  
• Fallopian Tube problems. They could be blocked, sometimes because of an inherited difficulty, or because of an infection of the womb or other diseases such as salpingitis (inflammation of the fallopian tubes), endometriosis, and TB; these may cause thickening of the tubes which either narrow or completely block the passages, or they can cause the tubes, uterus and ovaries to become matted together by adhesions, or in the case of endometriosis, by growths of tissue from the uterus.
  
• Prolapse & Fibroids. There could be malposition of the uterus or fibroids which can lead to sterility. The latter can also cause miscarriage early on, or a difficult labor. It is best to sort out this problem before conceiving. Their origin is largely related to a hormonal imbalance with an excess of oestrogen.
  
• Cervical problems. The cervix can also be affected adversely and cause sterility. Infection or excess mucus from inflammation can expel the sperm, or polyps may prevent the sperm from entering the uterus.
  
• Non-physical causes. In many women there are absolutely no physical problems to be found. There may be a slight hormonal imbalance or a poor state of health through faulty diet and fatigue. In perhaps a quarter of all infertile women it is emotional problems which are to blame.