Week 13: Urine forms
Week 14: Baby's sex becoming apparent
Week 15: Baby's scalp pattern develops
Week 16: Baby's eyes move
Week 17: Baby's toenails develop
Week 18: Baby begins to hear
Week 19: Baby develops protective coating
Week 21: Baby can suck his or her thumb
Week 22: Baby's hair becomes visible
Week 24: Baby's skin is wrinkled
Week 26: Baby's lungs develop
Week 27: 2nd trimester ends
Content
Week 13: Bones start to harden
Week 14: Red blood cells form
Week 15: Bone development continues
Week 16: Eyes move
Week 17: Toenails develop
Week 18: Hearing develops
Week 19: A protective coating forms
Week 20: The halfway point
Week 21: Baby can suck a thumb
Week 22: Hair becomes visible
Week 23: Fingerprints and footprints form
Week 24: Skin is wrinkled
Week 25: Baby responds to your voice
Week 26: Eyebrows and eyelashes form
Week 27: Second trimester ends