Baby by Week
Week 12

Your week 12 guide

Most internal systems are now formed and will keep growing and maturing throughout pregnancy.
Trimester

1

Month

3

Weeks left

28

Size at a glance

Comparison
Lime
Length
5.1–6.4 cm
Weight
0.5 oz
Measurements are approximate. Healthy babies grow at different rates.

Baby development

The kidneys make urine and the intestines fit inside the abdomen.
Digestive muscles practice contractions.
Vocal cords develop and the baby's profile may be clearer on ultrasound.

Your body

Nausea may ease while bloating, gas, or constipation continues.
Lower blood pressure can contribute to light-headedness.
A fetal heartbeat may be heard during a visit, depending on positioning and equipment.

This week's checklist

Review food safety and alcohol avoidance with trusted clinical guidance.
Plan for clothes that accommodate your changing body.
Ask what screening results mean for your individual pregnancy.

Call your care team

Call for bleeding, repeated dizziness, or vomiting that prevents hydration.
Seek urgent help for heavy bleeding, severe pain, 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.