Within 24 hours after fertilization, the egg that will become your baby rapidly divides into many cells. By the ninth week of pregnancy, the embryo develops into a fetus. There are about 40 weeks to a typical pregnancy. These weeks are divided into three trimesters.

The embryonic stage happens first and lasts through week 10. The fetal stage comes next and lasts from the end of week 10 until you give birth.

Fundus: The uppermost and widest part of your uterus. It connects to your fallopian tubes.

Corpus: The main body of your uterus. This is where a fertilized egg implants during pregnancy.

Isthmus: The part of your uterus between your corpus and cervix. ...

Cervix: The lowest part of your uterus.