How big is the baby in week 12 of pregnancy?

In week 12, your baby is roughly 5.4 cm long and weighs about 14 g — about the size of lime.

12 of 40 weeks

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First trimester

Week 12

You're nearly through your first trimester.

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Baby size this week

As lovely as a lime

Measurements are averages — every baby grows at their own pace.

Length 5.4 cm 2.1 in

Weight 14 g 0.49 oz

Your baby this week

Reflexes are getting more responsive
Tiny fingernails are beginning to form
The kidneys are now producing urine
Facial features are moving into place

Your body this week

Nausea

Fatigue

Bloating

Headaches

A little list for week 12

This week's to-do

Book your next prenatal appointment Start a gentle pelvic floor routine Write down questions for your midwife Consider comfortable maternity leggings Maternity leggings that grow with youHelpful pick

How we measure week 12

Pregnancy weeks are counted from the first day of your last menstrual period, following standard ACOG and NHS guidance. Sizes are crown-rump length in early weeks and head-to-heel from around week 20. Your care team may adjust dates after an ultrasound.

Continue to week 13

BumpCount offers general information and does not replace advice from your doctor or midwife.

Week 12

As lovely as a lime

Your baby this week

Your body this week

This week's to-do

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