3 Weeks Pregnant
At 3 weeks pregnant, your baby is a tiny ball of cells, a speck of stardust.
- Trimester
- First
- Month
- Month 1
- Weeks to go
- 37
Stardust
Your baby at 3 weeks
Conception happens! Sperm meets egg in the fallopian tube and forms a single cell, the zygote, which already carries all of your baby's DNA. It divides again and again as it travels to the uterus, becoming a ball of cells called a blastocyst.
Your body at 3 weeks
You will not feel pregnant yet. Around the end of this week the blastocyst begins to implant into your uterine lining, which some people notice as light spotting.
Common symptoms at 3 weeks pregnant
- Possible light implantation spotting
- Mild cramping
- No symptoms at all is completely normal
Every pregnancy is different. Having none of these symptoms is normal too.
Tips for week 3
- It is too early for a home pregnancy test; wait until your period is late.
- Avoid alcohol, smoking and recreational drugs.
- Check any medicines with a pharmacist or doctor.
Your week 3 checklist
- Avoid alcohol, smoking and recreational drugs
- Keep taking folic acid
- Wait to test until your period is late
Helpful at 3 weeks
3 Weeks Pregnant: your questions answered
How big is a baby at 3 weeks pregnant?
At 3 weeks your baby is a tiny ball of cells called a blastocyst, far too small to measure. The Prego app shows this stage as stardust.
How many months is 3 weeks pregnant?
3 weeks pregnant is month 1 of your pregnancy, in the first trimester. Your due date is 37 weeks away.
Can I take a pregnancy test at 3 weeks?
It is usually too early. The embryo is only just implanting, so hCG levels are too low for most tests. Test from the day your period is due for the most reliable result.
Sources
This guide is written from public guidance by the American College of Obstetricians and Gynecologists (ACOG), the NHS, the CDC and the World Health Organization. Baby sizes are averages; your baby may be bigger or smaller and still perfectly healthy.
General information only, not medical advice.
History of updates
- : Added a weekly checklist and common questions.
- : Matched fruit, length and weight to the Prego app.
- : Published.