13 WEEKS PREGNANT
Vocal cords begin to form
Baby this week: about 7.4 cm — crown to rump · about 23 g
≈ 7.4 cm — about the size of a plum
Illustration enlarged for clarity — the amber marker shows true relative size
Your baby this week
- Vocal cords start to form, though there's no air yet to make sound
- Fingerprints are starting to form as tiny ridges appear on fingertips
- The placenta is now fully functioning, taking over hormone production
- The fetus can make sucking motions with its mouth
Your body this week
- Many people notice an energy rebound as they move into the second trimester
- Round ligament twinges — quick stretches on the side of the belly — can start as the uterus grows
This week's tip: If nausea has eased, this is a good stretch to focus on regular, balanced meals and gentle movement.
Want the bigger picture — organ development, nutrition, scans and warning signs for this stage? See month 3: The first trimester finish line.
Sizes and milestones are typical ranges — every pregnancy runs on its own clock. Educational content; your prenatal care team's guidance always comes first.