At 4 weeks pregnant you are in the first trimester, with about 36 weeks to go until a 40-week due date. Weeks are counted from the first day of your last period, so this is roughly month 1 of pregnancy.
How big is your baby at 4 weeks?
Around week 4, your baby is often compared to a poppy seed. Fruit and vegetable comparisons are a friendly way to picture the size, not an exact measurement.
The first trimester runs to the end of week 13. It is when the baby's main organs and body systems start to form, and many people feel tired, queasy or both.
Your body at 4 weeks
Often the week of a missed period. You may feel nothing yet, or notice a little tiredness, sore breasts or light spotting.
What is going on
Your body is making hCG, the hormone a pregnancy test picks up, and progesterone is rising to keep the womb lining ready. This hormone surge is behind early tiredness and tender breasts.
What can help
Start folic acid if your doctor has not already asked you to, and avoid alcohol and smoking.
Other weeks
5 weeks pregnant ยท 6 weeks pregnant
See all weeks on the pregnancy week by week page, or try the interactive week-by-week guide.