A pregnancy is divided into three trimesters, each lasting approximately three months:
- First trimester: from conception or the first day of the last menstrual period to about 12–13 weeks.
- Second trimester: from about 13–14 weeks to 26–28 weeks.
- Third trimester: from about 27–28 weeks until birth, around 40 weeks.
Each trimester marks distinct developmental stages for the fetus and different physical experiences for the pregnant person
