From the first precious weeks of new life it's all systems go for your and your child.

Week 1
Now is the time to stop smoking and seriously limit your intake of alcohol. Avoid unnecessary over-the-counter or prescription drugs. Make plans to leave work if it poses a risk to your pregnancy, for example exposure to toxic chemicals or x-rays.

Week 2
Although it still appears to be just a tiny bundle of cells, the sex of your baby is already determined by the type of sperm that fertilised your egg. If the sperm carried an x chromosome, you will have a girl, if it carried a y chromosome it will be a boy.

Week 3
This bundle of cells, called a ‘blastocyst’, buries itself in the top of your uterus and puts down tiny roots into the lining. These will become the placenta.

Week 4
You may experience queasiness or heavy breasts as the levels of pregnancy hormone increase. This week the blastocyst becomes an embryo made out of three distinct types of tissue. The inner layer becomes the lungs, liver, digestive system and pancreas. The middle layer will turn into the skeleton, muscles, kidneys, blood vessels and heart, and the outer layer will grow to be the skin, hair, eyes, teeth and nervous system.

• The early signs of pregnancy