Week 6 of Pregnancy
A fetal heartbeat becomes visible on early ultrasound, and limb buds begin to grow.
Fetal size
Sweet pea
- Length
- 0.5 cm
- Crown-rump (CRL)
- Weight
- Not yet measurable
Fetal development
- The heart beats at roughly 100–150 bpm and may be detected on transvaginal ultrasound.
- Tiny arm and leg buds appear and facial structures begin to form.
- The embryo is about 5mm long.
Maternal changes
- Morning sickness, fatigue, and breast tenderness often peak this week.
- Smells may suddenly become intense; food preferences can swing wildly.
Recommended checkups
- The first prenatal ultrasound often confirms the gestational sac and heartbeat around now.
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Textbook averages. Individual variation is wide and this is not medical advice — confirm with your OB.