Why It Takes About 12 Days for Implantation – Introducing the Mystery of Human Conception Before we understand why it takes about 12 days for human implantation, we first need to understand the process of conception. The human conception process is roughly divided into three stages: ovulation, fertilization and implantation. This article will introduce the mystery of human conception from the following four aspects. 1. The impact of women’s menstrual cycle on women’s menstrual cycle