How accurate is a due date?

A due date is an estimate. Only about 1 in 20 babies arrive on it; most are born within two weeks either side.

Can my due date change?

Yes — early ultrasound measurements can refine it. Later scans usually do not shift an established date.

Are these baby-size comparisons exact?

The fruit and vegetable comparisons are friendly approximations of average length. Every pregnancy is unique — your baby may be a little larger or smaller.

Week 4 of pregnancy

4 Weeks Pregnant

First trimester

Baby size

About the size of a poppy seed

0.2 cm

What's developing

The embryo implants into the uterine lining. Some people notice light spotting. A pregnancy test may just start to turn positive.

Common symptoms this week

Implantation spotting
Tender breasts
Fatigue
Missed period

This is an estimate for information only — only about 1 in 20 babies arrive on their due date. Always confirm dates with your midwife or doctor.

Frequently asked questions

Jump to another week

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40