First trimester (up to week 12)
Week 1 begins on the first day of your last period. Start taking 400 micrograms of folic acid a day as soon as you decide to start trying for a baby and up until week 12 of your pregnancy. By now the sex of your baby is already set and by week six you may get morning sickness. Limit caffeine by swapping tea and coffee for refreshing peppermint tea.
By week nine, your baby is growing tiny hands and feet and is around 22mm long. Your first antenatal appointment comes near the end of this trimester and at your week 12 scan you'll see your baby's heartbeat for the first time.
Second trimester (week 13 – week 27)
By now, lots of people announce they're pregnant and show their scan pictures. If you need an amniocentesis, which checks for any signs of or potential for abnormalities or serious conditions in unborn babies, you'll often have this between week 15 and 20.
Between weeks 18 and 20 you'll usually have a foetal anomaly scan, which checks all is well with your baby's development and where the placenta is lying in your uterus.
From week 17 or 18, you may feel baby movements and two weeks later, your baby can hear sounds from outside so talk and sing to your bump. From around week 20 you may need maternity clothes, notice stretch marks, or find you experience indigestion as baby takes up more space.
Third trimester (week 28 – week 40)
Baby's nearly here, so you'll have antenatal appointments every two to four weeks to check you and your baby's progress. Your body is preparing for breastfeeding, so your breasts might leak. From week 32 baby may move into position with their head pointing down – a pregnancy support pillow can help you get comfortable in bed.
From around week 34 you could feel practice contractions called Braxton Hicks. From 37 weeks your pregnancy is considered full-term and most women go into labour between 38 and 42 weeks.
Prepare your hospital bag early in case your baby arrives sooner than expected, then relax as much as possible. The NHS also recommends taking your antenatal notes wherever you go, so your pregnancy information is easily to hand in case you require medical attention when you are out and about.