infertility information

Conception is when a woman’s egg is fertilised by a man's sperm, and is the process that begins pregnancy. Most couples don't have a problem achieving pregnancy.

For these couples, regular unprotected sex is all it takes to conceive a child.

If you’re trying for a child or thinking of doing so in the future, knowing the basic facts about fertility can be helpful.

The monthly cycle

Every month, hormonal changes in a woman’s body cause the ovaries to release a single egg. This egg passes into the fallopian tubes, which link the ovaries to the uterus or womb.

At the same time, the lining of the womb thickens. This is to prepare it for the possibility of receiving a fertilised egg.

If fertilisation does not occur, the womb lining will break down and will be shed through the vagina. This is a woman’s period. The period is made up of the womb lining and a small amount of blood.

Sexually mature females have a period approximately every 28 days, although between 24 and 35 days is common.

If the woman has unprotected sex within days of the egg being released, sperm from her male partner may fertilise her egg while it is in the fallopian tube. The fertilised egg will then travel to the womb and become embedded in its lining, where it will start to grow.

How conception occurs

Once an egg has been released from the ovaries, it can be fertilised by sperm within 12 to 24 hours.

Sperm can survive in the fallopian tubes for up to 72 hours, so fertilisation can occur even if sperm entered the fallopian tubes before an egg was released.

During conception, a single sperm from a man penetrates the egg of a woman. The sperm carries the father’s genes, while the mother’s genes are contained in the egg. Once the egg has been fertilised by a single sperm, no more sperm can enter.

The fertilised egg, called a zygote, continues to move down the fallopian tubes, until it reaches the uterus three to seven days later. Here, it will implant itself into the lining of the uterus, where it begins to grow.

Until eight weeks after conception, the implanted zygote is called an embryo. After this, it is a foetus.

For most women, the first sign that they are pregnant is a missed period. A few days after that missed period, a urine test can confirm the pregnancy.

Urine tests for pregnancy are available through your GP or family planning clinic, and are often available at your local pharmacy.

If you're trying to get pregnant

If you're trying to conceive, you can find more advice in

help getting pregnant.