Major Causes of Infertility

It is estimated that one in six couples face difficulties in conceiving. If you've had unprotected sex for more than 12 months (or, if you're over 35, six months) and are still not pregnant, you may begin to wonder if you are infertile.

If you decide to seek medical help, the best thing to do is see your doctor. Many infertility problems can be pinpointed and the vast majority treated.

The chart below outlines the most common causes, typical treatments and the percentages of couples who go on to become pregnant. Percentages are variable since multiple problems can exist in a couple. Read more about infertility treatments in our treatment chart.

FEMALE -- accounts for 35-40 per cent of all fertility problems
Condition: Endometriosis
Definition	This condition, in which endometrial tissue (the uterine lining that sheds with each monthly period) grows outside the uterus, is a major cause of infertility in women.
Possible symptoms	Painful menstrual periods, irregular or heavy bleeding and possibly, repeated miscarriages.
Possible solutions	Laparoscopic surgery to remove abnormal tissue or unblock tubes and assisted conception treatments.
Success rates	Surgery: 40-60 per cent conceive within 18 months after surgery. IVF: usual expected success rates
Condition: Ovulation problems
Definition	Any condition (usually hormonal) that prevents the release of a mature egg from an ovary.
Possible symptoms	Absent or infrequent periods and excessively heavy or light bleeding.
Possible solutions	Ovulation-stimulating drugs such as clomiphene, follicle-stimulating hormones, human chorionic gonadotrophin (HCG) and in vitro fertilisation (IVF) using these drugs.
Success rates	70 per cent ovulate and of those, 20-60 per cent get pregnant.
Condition: Poor egg quality
Definition	Eggs that become damaged or develop chromosomal abnormalities cannot sustain a pregnancy. This problem is usually age-related -- egg quality declines significantly in the late 30s and early 40s.
Possible symptoms	None.
Possible solutions	Egg donation or surrogacy.
Success rates	43 per cent of women who have a fertilised donor egg implanted become pregnant.
Condition: Polycystic ovary syndrome
Definition	Patients whose ovaries contain many small cysts have hormone imbalances and do not ovulate regularly.
Possible symptoms	Irregular menstrual periods, excessive hair growth, acne and weight gain.
Possible solutions	Ovulation-stimulating drugs such as clomiphene, follicle-stimulating hormones, and IVF.
Success rates	70 per cent who take fertility drugs ovulate and of those, half go on to conceive within six to nine months. Unfortunately, one in five of those pregnancies miscarries.
Condition: Female tube blockages
Definition	Blocked or damaged fallopian tubes prevent eggs from getting to the uterus and sperm from getting to the egg. Leading causes include pelvic inflammatory disease, sexually transmitted diseases such as chlamydia, and previous sterilisation surgery.
Possible symptoms	None.
Possible solutions	Laparoscopic surgery to open tubes, if possible (small area of blockage). If surgery fails, in vitro fertilisation is an option.
Success rates	Conception rates vary widely -- from a low of 10 per cent to a high of 70 per cent -- depending on the severity of the blockage and the amount of scar tissue that develops after surgery. IVF: usual success rates.

MALE -- accounts for 35-40 per cent of all fertility problems
Condition: Male tube blockages
Definition	Any obstructions in the vas deferensor epididymis (the tubes that transport fertile sperm). Varicoceles (varicose veins) in the testicles are the most common cause of male tube blockages. Sexually transmitted diseases, such as chlamydiaor gonorrhoea, are also linked to tube blockage problems.
Possible symptoms	None.
Possible solutions	Surgery to repair the varicoceles or other obstruction.
Success rates	About 40 per cent are able to impregnate their partner within a year of surgery, most within six to nine months.
Condition: Sperm problems
Definition	Low or no sperm counts, poor sperm motility (the ability to move), and abnormally-shaped sperm can all cause infertility.
Possible symptoms	None.
Possible solutions	Fertility drugs may boost sperm production. Other options include artificial insemination with donor sperm and injecting sperm directly into the egg (intracytoplasmic sperm injection).
Success rates	Fertility drugs: About 25 per cent are able to impregnate a partner. Artificial insemination: 5-20 per cent of women become pregnant per cycle. Sperm injection: About 15 per cent of women get pregnant per attempt.
Condition: Sperm allergy
Defintion	Fewer than 10 per cent of infertile women and men have immune reactions to sperm, which cause them to produce antibodies that kill sperm cells. In men, this is most common after a vasectomy. This diagnosis is controversial: Click here to learn more.
Possible symptoms	None.
Possible solutions	Sperm washing and intrauterine insemination, assisted conception treatments. Immunosuppressive drugs, such as cortisone and prednisone, are sometimes used but many doctors don't recommend them.
Success rates	Success rates of 20-40 per cent per cycle have been reported for all these treatments, but these figures are considered controversial.

Unexplained and combination -- accounts for 20-35 per cent of all fertility problems
Condition: Unexplained infertility
Definition	This catch-all term is used when doctors can't find a cause for infertility after a full series of tests and assessments. Some experts think being significantly over- or underweight, exercising excessively and even environmental toxins may be contributing factors but no direct links have been confirmed.
Possible symptoms	None.
Possible solutions	Beyond timed intercourse, there is no specific treatment. Some couples try fertility drugs and assisted conception procedures such as in vitro fertilisation, which have usual success rates. Others decide not to have children.
Success rates	How long the couple has been infertile is important. Couples with unexplained infertility who have been trying for less than five years have about a 15-30 per cent chance of becoming pregnant in a given year. After five years, fewer than 10 per cent become pregnant without treatment.
Combination infertility
Definition	The term used to describe couples who have both male and female infertility problems, or when one partner has more than one fertility problem.
Possible symptoms	Symptoms vary, depending on causes.
Possible solutions	Once all infertility causes are determined, appropriate treatments follow.
Success rates	Rates vary, depending on infertility causes.