Gestation stages
Pregnancy is measured from the first day of your last menstrual period and lasts about 40 weeks. We break it into weekly progress with plain-language milestones for each trimester.
First trimester (weeks 1–13)
Major organ systems form. Common feelings: fatigue, nausea, tender breasts, mood shifts. The heartbeat is usually detectable around week 6–7. Prenatal care starts here.
Second trimester (weeks 14–27)
Often the most comfortable stretch. Energy returns, the bump becomes visible, and you feel first movements (~18–22 weeks). Anatomy scan around week 20.
Third trimester (weeks 28–40)
Baby gains weight rapidly. Braxton-Hicks contractions, back discomfort, and trouble sleeping are common. Weekly checkups begin around week 36. Full term is 39–40 weeks.