The first three months of pregnancy

These 12 weeks are full of changes to your body and lifestyle. Here's what's happening.

Pregnancy lasts around 40 weeks and is sometimes divided into three stages called 'trimesters', each lasting around 13 weeks.

Weeks 1 to 4

You
Your pregnancy is dated from the first day of your last period, although conception usually takes place about two weeks after that, around the time that you ovulate (release an egg). In the first four weeks of pregnancy, you probably won't notice any symptoms. The first thing most women notice is that their period doesn't arrive.

To work out when your baby is due, see the pregnancy calendar .

Your baby
The cells of your fertilised egg are multiplying quickly, and the bundle of cells implants in your womb lining around five to seven days after the egg is fertilised by a sperm.

Tip: routine dental work is free during your pregnancy and for the first year of your baby's life. Your gums may become more sensitive when you're pregnant, so it's especially important to visit at this time.