Baby by Week
Week 5

Your week 5 guide

The embryo is forming three cell layers that will become every organ and tissue.
Trimester

1

Month

2

Weeks left

35

Size at a glance

Comparison
Sesame seed
Length
Very small
Weight
Too small to weigh
Measurements are approximate. Healthy babies grow at different rates.

Baby development

The outer layer contributes to the brain, nervous system, skin, eyes, and ears.
The middle layer forms structures such as the heart, bones, muscles, and kidneys.
The inner layer develops into organs including the lungs, liver, bladder, and intestines.

Your body

A missed period, sore breasts, fatigue, nausea, and extra saliva may appear.
Your belly usually looks unchanged this early.
Symptoms vary widely and may come and go.

This week's checklist

Book your first prenatal appointment.
Ask about nutrition, prenatal vitamins, and a healthy weight range for you.
Use a simple notes list for questions you want to ask.

Call your care team

Seek help if vomiting prevents you from keeping fluids down.
Report bleeding, severe or one-sided pain, shoulder pain, dizziness, or fainting urgently.

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.