3 min read · Around weeks 9–12 of pregnancy
Three months pregnant can feel like an important turning point. Your baby is still tiny, but the changes happening inside the womb are remarkable.
Between approximately weeks 9 and 12, the face becomes more recognisable, fingers and toes develop, the body begins to straighten and major organs continue their early development.
By the end of this period, your baby may be only around the size of a plum — but already looks much more like the little person you will eventually meet.
How big is your baby at 3 months pregnant?
Growth is rapid during these four weeks.
- Week 9: approximately 22 mm from head to bottom.
- Week 10: approximately 30 mm.
- Week 11: approximately 41 mm.
- Week 12: approximately 5.4 cm — roughly the size of a plum.
These measurements are averages. Your healthcare team will use appropriate clinical measurements rather than fruit comparisons to assess your individual pregnancy.
What develops between weeks 9 and 12?
At around nine weeks, the face is becoming more defined. Eyelids are forming, the mouth and tongue are developing and the hands and feet continue taking shape.
Inside the body, major organs including the brain, heart, lungs, kidneys and digestive system are developing. The skeleton begins forming and gradually starts hardening from softer tissue into bone.
Over the following weeks, fingers and toes become more distinct. Tiny fingernails and ears appear, while the body grows quickly in relation to the still relatively large head.
By around week 12, the internal organs and muscles have developed considerably and the skeleton continues to harden.
Can your baby move at three months?
Yes. Your baby can already make small movements inside the uterus.
You are unlikely to feel them yet. The first movements that a parent can recognise usually come later in pregnancy, and exactly when that happens varies considerably.
For now, all that activity is happening quietly in the background.
What happens next?
As you move into the second trimester, your baby will grow rapidly. Bones will continue hardening, movements will become more coordinated and the body will slowly become more proportionate.
For the bigger picture, explore our pregnancy development month-by-month guide.
Hello World Kit | 0–6 months
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Frequently asked questions
How big is a baby at 12 weeks pregnant?
At around 12 weeks, an average fetus measures approximately 5.4 cm from head to bottom, although individual measurements vary.
Can a baby move at 12 weeks?
Yes. Small movements are already happening, but you will usually not be able to feel them yet.
Are the major organs formed by 12 weeks?
The major organ systems have begun developing by this stage, but they are not mature and development continues throughout pregnancy.
Can you tell the baby's sex at 12 weeks?
External sex characteristics are developing, but most routine scans cannot reliably determine the baby's sex this early.
The Owloo approach
At three months, so much of pregnancy is still invisible from the outside.
But inside, an extraordinary little body is taking shape.
Tiny changes. Quiet growth. A story already beginning.
Written by Tina Krapez, Owloo Co-founder & COO
Tina Krapez is the Co-founder and COO of Owloo, where she helps create thoughtful products and educational resources for families from pregnancy through their baby's earliest stages of development.
Sources and further reading
