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Fetal development: The second trimester
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
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
Content
As pregnancy moves into the second trimester, your baby may begin to seem more real. At four weeks of pregnancy, your baby was a cluster of cells. At 11 weeks, the unborn baby became a fetus. Now, the organs, nerves, and muscles are starting to work. Use this information to follow along with what's happening week by week during the second trimester.
As you track your pregnancy, remember that to find your estimated due date, your healthcare professional counts ahead 40 weeks from the start of your last period. That means you're actually not pregnant the first week or two of what's counted as your pregnancy's 40-week timeline.
