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Pregnancy Trimesters Week by Week: Simple Overview

WellnessCalcs Guide
Reviewed for clarity and educational use. Last updated 2026.

Pregnancy is commonly divided into three trimesters. Each trimester includes different developmental milestones and different experiences for the pregnant person. Due date calculators can help estimate timing, but every pregnancy is different.

First trimester

The first trimester usually covers weeks 1 through 12. Early development begins, and many people experience fatigue, nausea, and breast tenderness.

Second trimester

The second trimester usually covers weeks 13 through 26. Many people feel more energy, and fetal movement may become noticeable later in this stage.

Third trimester

The third trimester usually begins around week 27 and continues until birth. This stage often focuses on growth, monitoring, and preparing for delivery.

Use our pregnancy due date calculator to estimate due date, trimester, and pregnancy progress.

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Disclaimer: This article is for general education only and does not replace advice from a qualified professional.