First Trimester

4 Weeks Pregnant

Discover what happens at 4 weeks pregnant. Learn about early pregnancy symptoms, baby development, and important first steps for a healthy pregnancy.

👶 Your Baby This Week

🌱

Size of a poppy seed

0.04" (0.1 cm)

Development Highlights

  • ✓Embryo implants in the uterine wall
  • ✓Amniotic sac and placenta begin forming
  • ✓Neural tube (future brain and spinal cord) starts developing
  • ✓Heart tube begins to form

🤰 Common Symptoms This Week

  • •Missed period
  • •Light spotting (implantation bleeding)
  • •Breast tenderness
  • •Fatigue
  • •Mild cramping

💡 Tips for Week 4

  • 1Take a home pregnancy test
  • 2Start taking prenatal vitamins with folic acid
  • 3Schedule your first prenatal appointment
  • 4Avoid alcohol, smoking, and harmful substances

🔍 Ultrasound at Week 4

What can be seen:

  • 👁Gestational sac may be visible

Related Resources

📅 Due Date Calculator

Calculate your estimated due date

👶 Baby Size Calculator

Fun size comparisons for each week

📖 8K vs 3D/4D Ultrasound

Learn about ultrasound technologies

✨ Get 8K Ultrasound Portrait

Transform your ultrasound into art