What are the signs of successful implantation?
What are the signs of successful implantation?
An embryo must be in the blastocyst stage before it may attach to the endometrium. It consists of two well-differentiated portions and has 200–400 cells at this stage of development.
- Internal cell mass: cells from which the embryo itself will develop.
- Trophectoderm: the outermost cells, which are responsible for creating the placenta and other embryonic attachments.
The blastocyst must also have reached its maximum degree of expansion—the hatched blastocyst—and have disengaged from the zona pellucida, the covering that covers it, before it can be implanted. The quality of the embryo, which can only be assessed in patients undergoing in vitro fertilization (IVF) treatment, is another important aspect that will determine if implantation takes place. On the other hand, the proper transfer of the embryo from the tube to the uterus must take place in cycles where fertilization naturally takes place in the fallopian tubes.