Baby Development Timeline

Follow your baby's incredible journey from the earliest weeks through birth.

Week 4

Implantation Begins

The fertilized egg implants in the uterine wall. Cells are dividing rapidly, forming the foundation for every organ and body system. The placenta is beginning to develop.

Week 6

Heartbeat Detectable

A heartbeat can be detected by ultrasound. The brain is developing rapidly, and tiny buds that will become the arms and legs are forming. Your baby is about the size of a lentil.

Week 8

Major Organs Forming

All major organs are beginning to form. Arms and legs are budding and growing longer. Facial features like the nose, lips, and eyelids are starting to take shape.

Week 10

Fingers & Toes Forming

Individual fingers and toes are now forming. Your baby can make small movements, though you won't feel them yet. Vital organs continue to develop and mature.

Week 12

Fully Formed

Your baby is fully formed with all organs, muscles, limbs, and bones in place. From here, the focus shifts to growth and maturation. Your baby is about 2 inches long.

Week 16

Facial Expressions

Gender may be visible on ultrasound. Your baby can now make facial expressions like squinting and frowning. The skeletal system is continuing to harden from cartilage to bone.

Week 18

Can Hear Sounds

Your baby can now hear sounds, including your voice and heartbeat. You may start to feel gentle fluttering movements known as "quickening."

Week 20

Halfway Point

You're halfway there! This is typically when the anatomy scan ultrasound is performed to check your baby's organs and growth. Your baby is about 10 inches long.

Week 24

Viability Milestone

Your baby is now considered viable outside the womb with intensive medical support. The lungs are developing air sacs, and the brain is growing rapidly.

Week 28

Eyes Open

Your baby's eyes can now open and respond to light. The nervous system is maturing, allowing your baby to respond to sounds and other stimuli with increasing awareness.

Week 32

Practicing Breathing

Your baby is practicing breathing movements and gaining weight steadily. Bones are hardening, though the skull remains soft and flexible for delivery.

Week 36

Nearly Ready

Lungs are nearly fully mature. Most babies move into a head-down position in preparation for birth. Your baby is gaining about half a pound per week.

Week 40

Full Term -- Ready for Birth

Your baby is full term and ready to meet the world! The average newborn weighs about 7.5 pounds and is 19-21 inches long. All systems are go for life outside the womb.

See Your Baby's Development Firsthand

Schedule a free ultrasound to see your baby and confirm how far along you are.

Schedule Free Ultrasound Call 770-535-1245