Pregnancy is commonly divided into first, second, and third trimesters. Each stage has different body changes, checkup priorities, and planning needs.
Pregnancy is commonly divided into first, second, and third trimesters. Each stage has different body changes, checkup priorities, and planning needs.
Pregnancy lasts about 40 weeks, divided into three trimesters based on fetal development and changes in your body. Knowing the focus of each helps you plan antenatal care and daily life.
The critical period for organ formation and the most important time for folic acid. Common symptoms include nausea, fatigue, breast tenderness and frequent urination. Key milestones: confirming the pregnancy, the first antenatal visit, and an early ultrasound to date the pregnancy, confirm it is in the uterus, and possibly an NT screen. Miscarriage risk is relatively higher, so rest and avoid harmful exposures.
For most people early symptoms ease and energy returns — often called the "golden period." First movements appear. Key screens include Down syndrome screening, the anomaly (anatomy) scan around 20 weeks, and gestational diabetes screening (OGTT) at 24–28 weeks.
The baby gains weight quickly and organs mature. Common discomforts include back pain, heartburn, leg swelling and Braxton-Hicks contractions. Visits become more frequent, with attention to movements, blood pressure and the baby's position as you prepare for birth. Term is 37 weeks; birth before 37 weeks is preterm.
At any stage, vaginal bleeding, severe abdominal pain, a severe headache or blurred vision, marked swelling with raised blood pressure, your waters breaking, or a clear drop in movements all warrant prompt medical attention.
The first trimester is weeks 1–13, the second is weeks 14–27, and the third is week 28 to birth, across roughly 40 weeks total.
The first is critical for organ formation and folic acid, with relatively higher miscarriage risk; the third needs close attention to movements, blood pressure and the baby's position. Each has its own key screens.
37 completed weeks is term; birth before 37 weeks is preterm, and beyond 42 weeks is post-term, which needs assessment by your provider.
Medical disclaimer: This guide is for general education and pregnancy date planning only and does not replace professional medical advice, diagnosis or treatment. For your individual situation, consult your doctor or midwife.
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Written and checked by the Pregnancy Tools editorial team · Last reviewed 2026-06-24 · About a 2-minute read · See About us