Fetal Development: Week 21
Size
Carrot
Length
6.9 in (17.5 cm)
Weight
12.7 oz (360 g)
Trimester
2nd
Your baby is the size of a carrot at 21 weeks. The digestive system is practicing, and white blood cells are forming to fight infections after birth.
Key milestone: The baby swallows more and their digestive system practices working. White blood cells form.
What's happening this week
At week 21, your baby measures 6.9 in (17.5 cm) and weighs approximately 12.7 oz (360 g) — about the size of a Carrot. Your baby is growing rapidly and becoming more active. The senses are developing, and movements are becoming stronger. This rapid growth is why tracking fetal development week by week is so exciting for expecting parents.
How to bond this week
Your baby can hear your voice now! Talk, sing, or read aloud. Baby Whispers voice notes complement these moments by arriving every morning like a little hello from your little one.
Common questions about fetal development at week 21
Parents at week 21 often ask how their baby is developing and what to expect at the next prenatal visit. Your healthcare provider will monitor growth through fundal height measurements and ultrasounds. Meanwhile, tracking fetal development week by week helps you understand the incredible transformations happening inside.
Looking ahead: what changes at week 22
Next week, your baby's development continues as they grow larger and more complex. Each week builds on the last, and the changes you're noticing now are preparing your baby for the milestones ahead. Baby Whispers evolves with each week too — our daily voice notes reflect your baby's changing world.
Prenatal Care at Week 21
Depending on where you are in your pregnancy, your prenatal appointments will focus on different aspects of care. Mid-pregnancy appointments include the anatomy scan (around 18-22 weeks), glucose screening, and monitoring your baby's growth through fundal height measurements. This is also when you may learn your baby's sex.
Your baby at week 21 — the size of a Carrot — is developing exactly as expected. Tracking fetal development week by week helps you feel connected to the incredible process unfolding inside you.
Hear your baby's voice at week 21
Imagine waking up to a voice note that sounds like your Carrot-sized little one.
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