4 weeks pregnant
Trimester 1
Your baby is about the size of a poppy seed.
What is happening at 4 weeks
Your baby is a tiny ball of cells settling into the lining of your uterus. The neural tube, which becomes the brain and spinal cord, is just beginning to form.
Not sure exactly how far along you are? Find your estimated due date and follow your pregnancy week by week.
Sizes and weights are typical averages and vary from baby to baby. This is general information, not medical advice. Your provider is the best guide to how your own pregnancy is progressing.
Sources and further reading
These organizations offer trusted, in-depth guidance. Gentle Apps is independent and not affiliated with them.