WOMEN: CAUSES OF SUBFERTILITY
A number of things are essential for a pregnancy to begin:
• there must be sufficient normal sperm in the semen
• sperm must be deposited in the vagina and move upwards through the cervix and uterus to the tube
• the woman must produce a healthy egg (ovum)
• the ovum must enter the fallopian tube and be moved along it
• one sperm must unite with the egg in the outer part of the tube
• the fertilised ovum must travel to the uterus and implant properly in its wall.
Anything interfering with any of these processes interferes with conception. Many things can break the conception chain.
Inadequate sperm production Often no cause for this can be found. Known causes include the testes not having descended into the scrotum; testicular disease that destroys the sperm-forming tissue; a mass of varicose veins, called a varicocele, in the scrotum, which keeps the temperature of the testis too high for sperm production; occupational factors such as working in a very hot environment or with certain other chemical or physical influences (a rare cause); some general health disorders, including a past history of mumps that has affected the testes; some treatments, particularly radiotherapy and chemotherapy for cancer. Excessive smoking and alcohol have been associated with reduced sperm count, and decreasing or stopping smoking and drinking may improve sperm production.
Disorders or disease of the spermatic ducts These ducts are the series of tubes that carry sperm from the testis to the ejaculate. Blockage of the duct system may result from scarring after previous infection, injury or surgery.
Irregular, infrequent ovum production This, or no ovulation, usually goes with a history of irregular, infrequent periods or no periods, though occasionally a woman may have regular menstruation without ovulating. This is basically a problem with the hormones that control ovulation.
Blockage of the passageway from ovary to uterus This may be due to adhesions resulting from peritonitis in the past, other pelvic infections such as those occurring after previous childbirth or surgery, or sexually transmissible infections such as gonorrhea or chlamydia; or endometriosis.
Cervical mucus that prevents sperm from getting through This may be due to an antibody in the mucus that kills the sperm or stops their movement, inflammation of the cervix. If a woman is ovulating, the hormonal influence produces cervical mucus that is optimal sperm penetration.
Less common reasons include problems with sexual intercourse (such impotence) so that the semen is not deposited in the vagina; congenital abnormalities of the reproductive organs; disorders of the lining or the wall of uterus; immunological problems.
The reason for subfertility is generally found to be around 40 per cent in the man, 40 per cent in the woman and 20 per cent in both. No reason can be found in about one in ten couples who conceive.
There are some old myths about conception that have proved wrong but many people still believe. You should know that:
• a woman doesn’t have to have of at intercourse to conceive
• a woman with a retroverted (backward-leaning) uterus is just as capable of conceiving as a woman whose uterus is in the forward-leaning position
• no position for intercourse is more likely than any other to result in pregnancy, as long as the semen is ejaculated
into the vagina
• adopting a child or taking out adoption papers will make no difference at all your chances of conceiving.
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