Pregnancy week by week / Week 4
4 weeks pregnant
That’s 1 month — the first trimester, with 36 weeks to go.
Baby size at 4 weeks
Your baby is about the size of a poppy seed — roughly the size of a poppy seed.
What’s happening at 4 weeks
The embryo has just implanted and a positive pregnancy test is likely. The neural tube — the start of the brain and spine — is forming.
Common symptoms at 4 weeks pregnant
- •Missed period
- •Light implantation spotting
- •Mild cramping
- •Tender, swollen breasts
- •Fatigue
Every pregnancy is different — you may have all, some or none of these. Contact your doctor or midwife about anything that concerns you.
Count down to your due date
If you’re 4 weeks pregnant today, your due date is around Tuesday, February 23, 2027. Adjust the date below and create a free countdown to share.
First day of your last menstrual period (how doctors date a pregnancy)
⚕️ This is an estimate based on Naegele’s rule (40 weeks from your last period). Only about 1 in 20 babies arrive on the exact due date. Always confirm with your doctor or midwife.
FAQ
How many months is 4 weeks pregnant?
4 weeks pregnant is about 1 month, in the first trimester.
How big is the baby at 4 weeks?
At 4 weeks the baby is about the size of a poppy seed — roughly the size of a poppy seed.
What are the symptoms at 4 weeks pregnant?
Common symptoms around 4 weeks include missed period, light implantation spotting, mild cramping, tender, swollen breasts. Symptoms vary a lot from person to person — contact your provider if anything worries you.
When is my due date if I am 4 weeks pregnant?
If you are exactly 4 weeks pregnant today, your estimated due date is around Tuesday, February 23, 2027 — 36 weeks from now. Use the calculator below with your real last-period date for a personalised estimate.
See every stage on the pregnancy week-by-week guide or open the full due date calculator.