Skip to main content
BumpStories
🫘

Week 4 of Pregnancy

Your baby is the size of a Poppy Seed

0.04 in (0.1 cm)0.001 oz (0.04 g)
First Trimester

Baby Development This Week

The fertilized egg has implanted in your uterus. The embryo is developing into two layers of cells from which organs and body parts will form.

What You Might Be Feeling

You might not feel any different yet. Some women experience light spotting (implantation bleeding) or mild cramping.

Medical Appointments and Tests

A home pregnancy test may show a positive result this week or next. Consider starting prenatal vitamins if you haven't already.

Frequently Asked Questions

How big is my baby at 4 weeks pregnant?

At week 4, your baby is about the size of a poppy seed — approximately 0.04 inches long and weighing about 0.001 ounces.

Is 4 weeks in the first trimester?

Yes, week 4 is in the first trimester, which covers weeks 1 through 12 of pregnancy.

What should I expect at 4 weeks pregnant?

At 4 weeks, your baby is the size of a poppy seed. Every pregnancy is different, but common experiences at this stage include physical changes, new symptoms, and exciting developmental milestones for your baby.

Want to know your due date?

Get your personalized pregnancy story card with milestones, zodiac sign, and more.

Calculate Your Due Date
Note: This calculator provides estimates based on standard medical formulas. Please consult your healthcare provider for personalized guidance.