What is the implantation site for a fertilized egg in a normal pregnancy?

• A. Ovary
• B. Fallopian Tube
• C. Uterus
• D. Cervix

Answer: (C)

Implantation occurs in the uterus, specifically into the thick, hormone-receptive endometrium. After fertilization in the fallopian tube, the embryo travels to the uterus and, under progesterone’s cue, the endometrium becomes a nourishing bed. The blastocyst adheres to and implants into this lining, and trophoblast cells begin to invade to establish the placenta and a steady blood supply. This uterine environment is the only normal site that can sustain a pregnancy long-term.

The other sites aren’t suitable for implantation in a normal pregnancy: the ovary releases the egg, the fallopian tube is where fertilization may occur but not where the embryo can be nourished and supported, and the cervix isn’t prepared to support implantation.