EMBRYOLOGY AND FETOLOGY

EMBRYONIC AND FETAL DEVELOPMENT

Postconception week 1: most significant event is the implantation of the
blastocyst on the endometrium.

Week 1 begins with fertilization of the egg and ends with implantation of the
blastocyst onto the endometrial surface. Fertilization usually occurs in the distal
part of the oviduct. The egg is capable of being fertilized for 12–24 hours. The
sperm is capable of fertilizing for 24–48 hours. Week 1 can be divided into 2
phases: