Cambridge O Level Biology · Syllabus 5090 · Development of Organisms and Continuity of Life
Implantation
What is Implantation?
The embedding of an early embryo, a ball of cells, into the thickened lining of the uterus. Implantation happens several days after fertilisation, once the embryo has travelled down the oviduct, and it is the point from which the placenta begins to develop.
This definition is part of the Development of Organisms and Continuity of Life chapter in Cambridge O Level Biology.
Common mistakes with Implantation
- “Fertilisation normally occurs in the uterus.” Why wrong It normally occurs in an oviduct. The uterus is where implantation happens, days later. Say instead Fertilisation: oviduct. Implantation: uterus.
Last reviewed Syllabus 2026-2028