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Infertility – an overview of common causes

There's a wide variety of reasons why couples may have difficulty conceiving - it's just as likely to be a male problem as a female problem, and doesn't necessarily require medical intervention

Posted: 8 July 2009
by ThinkBaby

Infertility is something of a misnomer, as it suggests that there is no chance of conception taking place at all, which is only true for a small percentage of couples. More commonly 'infertility' is used to refer to difficulties in conceiving (usually when a couple has actively tried conceiving for more than a year without success) but it doesn’t necessarily mean that the couple is incapable on conceiving at all, so a more accurate term would be subfertility.

Until relatively recently it was nearly always assumed that if there were problems in conceiving then it was the woman who was subfertile, in recent years however, studies have shown that it is every bit as likely to be the man who is subfertile, and often a combination of problems with both partners reduce the chances of conception.

What causes infertility?
Causes of fertility problems men and women experience can be separated into two main groups:

Lifestyle & dietary factors
Medical conditions & clinical factors

Lifestyle factors
If you’ve been trying for a baby for several cycles and aren’t getting anywhere, a good place to start looking for answers is in your own general health and diet. The following can cause problems:

  • Weight - Being very underweight or very overweight for women – both of these interfere with the levels of oestrogen in the body and can prevent ovulation
  • Smoking – In men, tobacco lowers sperm production. It could also lower a woman’s fertility and will almost certainly damage your unborn child if you do manage to conceive
  • Excessive caffeine consumption – there’s evidence that this can make it more difficult to conceive and maintain a pregnancy
  • Alcohol – heavy drinking has been shown to lower sperm production and may well cause fertility problems for women
  • Cycling, tight underwear and saunas – For men can inhibit the production of sperm by raising the temperature of the testes
  • Medications – numerous medications can interfere with sperm production, including: antimalarial medications, ulcer medications and steroids. In women prolonged use of antibiotics can result in yeast infections
  • Vaginal hygiene products – products for internal use in the vagina designed to clean or scent can alter the natural environment of the vagina and make it a hostile environment for sperm

Medical conditions & clinical factors

There are several stages in successfully establishing a pregnancy and a couple could have problems at any one, or more, of them. If you have tried unsuccessfully for one year to conceive, your doctor may begin investigations into the following:

Problems with ovulation:

  • Irregular cycles – irregular cycles make it very difficult to predict ovulation and to know when ovulation has taken place if you’re not charting your primary fertility signs. Irregular cycles are also a symptom of PCOS (see below)
  • PCOS – Polycystic Ovarian Syndrome – a number of small cysts on the ovaries release chemicals which can affect the balance of hormones and so prevent ovulation
  • Hypothyroidism – Low thyroid function can affect both men and women reproductively. For men it can lower the sperm count and in women it can impede ovulation or shorten the luteal phase. Once diagnosed the condition is usually treated relatively easily
  • Anorexia nervosa – Anorexics are highly likely to be clinically underweight and so unable to reach threshold levels of oestrogen to trigger ovulation

Problems with fertilisation/viable eggs and sperm:

  • Low sperm count – If a man’s sperm ducts are blocked, resulting in a low or zero sperm count, an operation will be necessary to try to treat the condition. But there needn’t be a physical blockage to produce a low sperm count, there’s evidence that deficiencies in certain vitamins and minerals – zinc, vitamins A and B – may cause low sperm production. As mentioned above, sperm production may also be compromised by over-warm testes
  • Damaged testes – injury or illness can occasionally damage the testes and inhibit sperm production
  • Poor sperm motility - poor ability of sperm to swim
  • Abnormal sperm/eggs – some men may produce abnormal sperm that is incapable of fertilising an egg, and some eggs may not be able to produce a healthy fetus even when fertilised
  • Ageing - As men and women grow older they produce fewer viable sperm and eggs: the decline in quality is starker and sets in earlier for women
  • A hostile environment for sperm – the woman may not be producing sufficient (or any) wet fertile quality cervical mucus to provide a suitable medium for the sperm to progress from the vagina through to the womb. When cervical mucus is too thick the sperm have difficulty swimming through it

Problems in implanting the fertilised egg in the womb:

  • Damage to the fallopian tubes – if the fallopian tubes are blocked, scarred or similarly damaged a successfully fertilised egg may not be able to make its way down into the uterus to establish the pregnancy. There are several possible causes of damage to fallopian tubes including infection, previous surgery and endometriosis
  • Short luteal phase – A fertilised egg needs time to make its way down into the womb and burrow into its lining. If your luteal phase (the phase between ovulation and menstruation) is fewer than 10 days long the lining of the womb may begin to disintegrate before a fertilised egg has time to implant and establish the pregnancy
  • Deficient uteral lining – The endometrium, or lining of the womb, may not develop to a sufficient thickness to sustain the pregnancy
  • Fibroids in the uterus – non-cancerous growths in the uterus that can cause heavy menstrual bleeding, irregular periods, obstruct the passage of the egg to the uterus and prevent the fertilised egg from implanting in the womb

Early miscarriage:
You may think that you are not able to conceive at all but actually have suffered a series of early miscarriages where your body has identified problems with the pregnancy in the early stages and discontinued it.

Working out what's wrong - where to start

Get healthy
It could be that reading this article prompts you to recognise lifestyle and diet issues that may be causing some difficulties, whether this is true or not, the best place to start is to make sure that both partners follow a healthy lifestyle and avoid the toxins and potential dietary and lifestyle hazards mentioned above.

Track your cycle
As we've seen above there are many different causes of subfertility, and the more information you can give your doctor about your cycle, the more quickly they may be able to rule out or unearth potential problems. If you are charting your temperature and fertility signs you may be able to help your doctor narrow down the possible causes as you should at least be able to tell whether or not you are ovulating. You may also be aware of early miscarriages that can occur before other women would even realise that they were pregnant. The more information you collect relating to your cycle, the more help this will be to the doctor.

See your doctor for a referral
Be aware that many doctors won't consider referring couples for fertility treatment until the couple has been trying for a year to conceive without success. If you are keeping a fertility chart which indicates a problem such as anovulation, early miscarriage or short luteal phase, then you may well be able to persuade your doctor to take action far earlier (and if not you may want to consider changing doctors). The doctor may also be prompted to take action earlier if it's clear from your chart that you're having sex at optimal times in the cycle yet still haven't conceived after six months.

If you're over 34 then you should see your doctor after six months without conceiving, so that no time is lost if treatment should be necessary.

Check out the man
If the causes of subfertility aren't obvious ones, such as dietary factors or anovulatory cycles, it makes sense to start medical examinations with the man. Why? Well, because there's a 50% chance that the problems may be down to problems with the man's sperm, there's a chance that the problem could be a combination of problems with both partners, and because it's relatively straightforward and less invasive to run tests on sperm samples, whereas it may take a series of involved tests to find out where the difficulties lie with the female.

Difficulties in conceiving can be a major cause of distress, and can put a great deal of strain on an otherwise happy relationship. If you're experiencing difficulties then try not to panic - remember that very many couples have some difficulties in conceiving, and that most of those will one day conceive and carry a healthy baby to term.

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