Fetal Development: Week 12
Size
Plum
Length
2.1 in (5.4 cm)
Weight
0.49 oz (14 g)
Trimester
1st
Week 12 marks the end of the first trimester for many. Your baby is the size of a plum and can now suck their thumb, swallow, and even hiccup.
Key milestone: The brain is rapidly developing. The baby can make sucking motions and swallow.
What's happening this week
At week 12, your baby measures 2.1 in (5.4 cm) and weighs approximately 0.49 oz (14 g) — about the size of a Plum. All major organs are forming or have formed, and the foundation for a healthy pregnancy is being established. This rapid growth is why tracking fetal development week by week is so exciting for expecting parents.
How to bond this week
Start talking to your baby even though they can't hear you yet — your voice will become familiar over time. Consider starting daily voice notes with Baby Whispers to build the habit early.
Common questions about fetal development at week 12
Parents at week 12 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 13
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 12
Depending on where you are in your pregnancy, your prenatal appointments will focus on different aspects of care. Early appointments confirm the pregnancy, establish your due date, and include blood work, urine tests, and sometimes an early ultrasound. Your provider will discuss prenatal vitamins, lifestyle adjustments, and what to expect in the coming weeks.
Your baby at week 12 — the size of a Plum — 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 12
Imagine waking up to a voice note that sounds like your Plum-sized little one.
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