Fetal Development Milestones 2
Week 1: Chromosomes from mum and dad combine – giving baby everything she needs to become a unique individual, from eye colour to fingerprints.
Week 2: Rapid and highly co-ordinated development is taking place.
Week 3: By day 22 the baby’s heart is beating, and her eyes are beginning to form.
Week 4: Facial features, arms and legs are developing. Her lungs are growing to prepare her for her first breath.
Week 5: Ears, hands and feet are developing. Baby’s brain has divided into distinct segments.
Week 6: Eyes are distinct. Most internal organs are present in basic form.
Week 7: Fingers, toes, eyelids and nose are almost complete. Baby is moving.
Week 8: Twenty teeth buds are forming in baby’s gums. Baby’s nervous system is responsive. Most of her joints have formed.
Week 9: All vital organs are fully formed. Baby can easily be seen kicking and jumping on ultrasound. She can yawn and suck.
Week 10: Baby’s fingernails and hair are growing. Baby’s vocal chords are forming.
Week 11: Baby responds to touch. She can be seen playing with her umbilical cord on ultrasound.
Week 12: Nervous system is functioning. Baby can suck her thumb.
Weeks 13–23: During the second trimester, baby’s growth is rapid. It’s an important time for the development of her senses. At 20 weeks baby is awake more often and can hear conversations, loud noises and music.
Weeks 24+ In the final trimester, baby’s brain undergoes dramatic development. Her weight triples as she lays down protective stores of fat in preparation for life outside the womb.