A new child is born in Australia every 2 minutes. Despite the enormity of these figures, and the large number of unplanned pregnancies reproduction is a finely balanced process depending on many factors in the male and female.

Somewhere between the age of 9 and 15 a young woman’s reproductive system matures. She starts having periods and is physically capable of pregnancy.

Each month a woman’s body is geared up for pregnancy. The ovaries contain thousands of immature eggs and many compete, to mature. Usually one egg dominates and matures rapidly and is expelled form the ovary in the process of ovulation. The egg is picked up by the fallopian tube and needs healthy sperm there and waiting, or at least there within 24 hours for fertilisation to occur. An unfertilised egg dies off quickly. Meanwhile the high hormone levels build up a lining on the womb, in preparation for a possible pregnancy. The egg travels through the fallopian tubes and if unfertilised is passed out through the cervix. It is so tiny you wont be able to see it. If there is no pregnancy the hormone levels drop. The thickened lining of the womb is no longer supported and falls away thus causing a period.

To help the process along the cervix (top part of the vagina) produces a special mucus (egg white like substance) that allows the sperm to quickly swim up to the fallopian tubes. This mucus also allows sperm to survive for long periods of time, occasionally up to 7 days.

If pregnancy occurs a chemical produced by the tiny placenta signals the body to continue high levels of hormone production to support pregnancy.

Young men begin to mature at a similar age to women, although often a little later. They have increased level of testosterone and begin to produce semen, containing sperm. The sperm take about 72 days to be produced and a further 12 to travel through the reproductive plumbing

Unlike women, men produce sperm continuously in high quantities. An average 1ml drop of semen contains about 40 million sperm.

How does contraception work

At its simplest level it acts as a barrier between sperm and eggs such as diaphragms and condoms. It may act to kill sperm, such as spermicides and IUDs, or it may stop a fertilised egg from sticking to the wall of the womb, as do IUDs. Hormonal methods either stop ovulation or thicken the mucus produced by the cervix to stop sperm getting through.

Infertility

With all these sperm about it is hard to imagine why falling pregnant can take some time. Even in absolutely ideal conditions only 30 % of women will achieve a pregnancy each month and a years wait is not considered abnormal. Commonly no reason is found for infertility. Frequently there may be a few subtle problems for both the male and female partner. It is usually a surprise to find you have a fertility problem.

Common causes of infertility

Women

Hormonal

Women are alerted to this by infrequent irregular periods. This is usually an easy problem to fix

Endometriosis

This is a common condition. It may affect fertility, although most women affected will not have trouble falling pregnant. Symptoms are painful periods and pain with sex.

Damaged tubes

This is commonly caused by a sexually transmitted infection such as chlamydia. These infections are frequently silent. It is important to have a check for these if you think you are at risk.

Men

For men the causes of low sperm counts are often not known. Known causes of male infertility are mumps infection as a child, trauma to the testicles and testicles that haven’t dropped into the scrotum. Uncommon genetic disorders may interfere with sperm production.

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Last updated:25/08/2005
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