Fetal development
Implantation and early cell division are the main story this week.
First trimester
A practical week 1 guide covering fetal development, symptoms, nutrition, prenatal tests, baby size comparison, and warning signs to discuss with your care team.
Implantation and early cell division are the main story this week.
Around week 1, baby is roughly comparable to a poppy seed. Estimated size: about 0.08 inches and 0.03 ounces, with natural variation.
This week-by-week pregnancy content is educational and does not replace care from a qualified healthcare professional.