4 weeks pregnant
At 4 weeks your baby is about the size of a poppy seed (about 1 mm). Here is what is happening for you both this week.
- Size
- a poppy seed
- Length · weight
- about 1 mm
- Trimester
- First
- Weeks to go
- 36
Your baby at 4 weeks
The ball of cells implants in the lining of the uterus. The placenta and amniotic sac begin to form.
Your body at 4 weeks
Your period is due. A home pregnancy test may now be positive. Some people have light spotting.
Your to-do list for week 4
- Take a pregnancy test if your period is late
- Book a GP appointment to confirm the pregnancy
Common questions
How many months pregnant is 4 weeks?
4 weeks is in month 1 of pregnancy and the first trimester.
How big is my baby at 4 weeks?
At 4 weeks your baby is about the size of a poppy seed (about 1 mm). Every baby grows at its own pace.
All 40 weeks
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
Useful tools
PregnancyDue date calculatorInstant due date, week and trimester.PregnancyPregnancy plannerEstimate dates and organise the weeks ahead.PregnancyAppointment trackerScans, tests, vaccinations and questions in one list.
Related guides
PregnancyPublic or private birth in Australia: costs and choicesHow public, private and midwife-led care differ, and what each usually costs.PregnancyMaking room for questions at your next appointmentKeep the things you want to ask in one easy-to-find place.PregnancyBuilding your support circle before baby arrivesSpecific offers of help are easier to accept.Dads & partnersA partner’s guide to pregnancyPractical ways to be involved from the first scan to the birth.