The average length of pregnancy is 40 weeks, starting from the first day of your last menstrual period to the birth of your baby, with most babies being born somewhere between 38 to 42 weeks.
Pregnancy is divided into 3 stages of 3 months each. Each of these stages is known as a trimester. The first trimester takes you to 12–14 weeks gestation, the second trimester up to 28 weeks gestation and the third trimester finishes with the birth of your baby.
Being aware of the specific ways that your growing baby is affecting your body in each trimester will help you to better prepare yourself for these changes as they happen. It’s also helpful to be aware of the specific risk factors and associated medical tests for each of the 3 trimesters.