Pregnancy

Trimester-by-Trimester Guide

What changes to expect and how to care for yourself each trimester.

6 min read Reviewed Sep 2026 Evidence-Based Education
Trimester-by-Trimester Guide

Your Pregnancy Journey

Pregnancy is divided into three trimesters, each with its own milestones, changes, and things to know. Understanding what's happening — and what to expect — can help you feel more confident and prepared as your baby grows.

First Trimester (Weeks 1–13)

Your body is working hard behind the scenes. The baby's organs are forming, and you may be feeling the effects of major hormonal changes.

  • What's happening: The heart starts beating, the brain and spine develop, and the baby grows from a cluster of cells to about the size of a peach
  • Common symptoms: Nausea (morning sickness), fatigue, breast tenderness, frequent urination, heightened smell
  • Key appointments: First prenatal visit (usually 8–12 weeks), dating ultrasound
  • What helps: Rest, small frequent meals, staying hydrated, and giving yourself grace
GOOD TO KNOW
Morning sickness can happen at any time of day. If you can't keep food or fluids down, call your provider.

Second Trimester (Weeks 14–27)

For many, this is the most comfortable trimester. Energy returns, the bump shows, and you'll likely feel those first exciting movements.

  • What's happening: The baby grows rapidly, can hear sounds, and develops hair and fingerprints
  • Common symptoms: Round ligament pain, backaches, skin changes, heartburn
  • Key appointments: Anatomy scan (around 20 weeks), glucose screening (24–28 weeks)
  • What helps: Gentle stretching, sleeping on your side, and starting to think about your birth plan

Third Trimester (Weeks 28–40)

The home stretch. Your baby is growing and gaining weight, and your body is preparing for birth.

  • What's happening: The baby practices breathing, gains fat, and settles into position for birth
  • Common symptoms: Braxton Hicks contractions, swelling, difficulty sleeping, shortness of breath
  • Key appointments: Visits become more frequent (every 2 weeks, then weekly), GBS test around 36 weeks
  • What helps: Packing your hospital bag, finalizing your birth plan, and resting as much as possible

What You Can Do

  • Keep all your prenatal appointments — they're scheduled to catch any concerns early
  • Start kick counts around 28 weeks
  • Take a childbirth education class in your third trimester
  • Pack your hospital bag by 36 weeks

Key Takeaways

  • First trimester: major development, morning sickness, and your first prenatal visit
  • Second trimester: energy returns, anatomy scan, and first baby movements
  • Third trimester: baby grows, Braxton Hicks, and more frequent appointments
  • Keep all prenatal visits — they're timed to monitor your health and your baby's

Still have questions?

Ask Nested AI can help — it knows you're reading about Trimester-by-Trimester Guide.

Nested Parent Hub

This app is for education and support only and does not replace medical advice. For medical concerns, contact your OB or midwife, pediatrician, or emergency services.

© 2026 Nested Baby. All rights reserved.