3 Weeks Pregnant
Week 3 is counted from the first day of your last period, so it happens before there is an embryo. It still matters: your body is preparing the conditions a pregnancy needs.
- Size of
- nothing yet — conception has not happened
- Length
- —
- Weight
- —
- Trimester
- 1
Your baby this week
- If sperm meets egg, fertilisation takes place in the fallopian tube.
- The single cell divides again and again as it travels towards the uterus.
Your body this week
- Hormone levels rise steadily to support the early pregnancy.
- The lining of the uterus thickens, ready for implantation.
Common symptoms
- Usually nothing at all — it is far too early for signs
- Bloating and a tight, full feeling in the belly
- Light spotting, which can be implantation bleeding
What to expect
Early pregnancy can feel invisible from the outside and very loud on the inside. Symptoms come and go from day to day, and that is normal. With 37 weeks to go, the priority this week is rest, gentle food and your first antenatal appointment.
Tips for this week
- Take a prenatal vitamin with folic acid and vitamin D.
- Stop alcohol and smoking, and check any medication with your doctor.
- Drink water through the day; dehydration worsens tiredness and headaches.
Frequently asked questions
How many months is 3 weeks pregnant?
3 weeks is about 0.5 months. Pregnancy months do not divide evenly into weeks, so counting in weeks is more precise.
How big is my baby at 3 weeks?
At 3 weeks your baby is around nothing yet — conception has not happened — roughly — long and about —. Healthy babies vary a lot around these averages.
What symptoms are normal at 3 weeks pregnant?
The most common ones this week are listed above. Contact your doctor or midwife about heavy bleeding, severe pain, a fever, or any change in your baby’s movements.
Pregnancy weeks are counted from the first day of your last period, so week 1 begins before conception.
This article is for general information only and is not medical advice. Always talk to your doctor or midwife about your own pregnancy.