Baby by Week
Week 13

Your week 13 guide

The first trimester is closing with stronger muscles, bones, nerves, and facial movement.
Trimester

1

Month

4

Weeks left

27

Size at a glance

Comparison
Lemon
Length
7.6 cm
Weight
1 oz
Measurements are approximate. Healthy babies grow at different rates.

Baby development

Mouth muscles can make early sucking motions and expressions.
Bone tissue is forming in the limbs and skull.
Vocal cords and internal organs continue to mature.

Your body

Energy and appetite may improve as nausea fades.
Vaginal discharge, heartburn, constipation, or indigestion can continue.
Your growing uterus and an audible heartbeat can make pregnancy feel more tangible.

This week's checklist

Decide when to share pregnancy news based on your own comfort and circumstances.
Review workplace needs, leave, and childcare early if relevant.
Continue prenatal care and note new questions for the second trimester.

Call your care team

Contact your clinician for bleeding, unusual discharge, painful urination, or persistent vomiting.
Seek urgent help for severe pain, heavy bleeding, fainting, chest pain, or difficulty breathing.

Medical information, not medical advice

Every pregnancy is different. Use this guide for general education and follow the advice of your own maternity care team. Do not delay urgent care because of something you read here.