FERTILISATION

Fertilisation occurs when a live sperm penetrates the newly released mature egg successfully and cell division starts. The woman has now conceived, the embryo is growing!

During sexual intercourse, millions of sperm are released into the vagina. As ovulation approaches, the cervical mucus becomes watery allowing the sperm to swim up the vagina through the cervix. At other times the mucus is more viscous and unreceptive to sperm. Only about 2,000 sperm will be strong enough to reach the uterus and the fallopian tube. 

The timing of sexual intercourse is very important for fertilisation to occur. The egg can only be fertilised for about 18-24 hours after it is released, so sperm must be present in the fallopian tubes around the time of ovulation. A man's sperm can only survive for about 3-5 days so a woman's fertile time will only be around 5-6 days every month, with the most fertile time being the 2-3 days up to and including ovulation.

Research suggests that even if intercourse takes place at the right time a normal healthy couple may still only have a 30% chance of fertilisation and pregnancy occurring. So don't be discouraged if pregnancy does not occur in the first month of trying..!

Once fertilised, an egg normally takes a few days to travel into the womb where it will need to implant itself in order for a viable pregnancy to begin. If this implantation happens the pregnancy hormone called Human Chorionic Gonadotrophin (hCG) starts to be produced. This hormone is vital for the maintenance of the lining of the womb and the new embryo and the amount of hormone produced rises rapidly, doubling approximately every two days, reaching a peak 60 to 80 days after conception. Soon after conception tiny amounts of this hormone can be detected in a woman's urine and this is what the early pregnancy test kits measure.