Can the embryo implant?

After the spermcell has found the oocyte and penetrated, the actual fertilisation takes place and we speak of an embryo. The Fallopian tubes will then actively transport the embryo in the direction of the uterus. To accomplish this transport the lining of the Fallopian tubes should not be damaged. For a cross-section of the Fallopian tubes: 1. click here and 2. click here.

Upon reaching the uterine cavity the embryo needs to implant in order to start growing. The capacity to implant and grow proofs the quality of the embryo. The ultimate proof of quality is of course a healthy newborn baby.

In 27% of the couples with a reduced fertility the reason is unclear. Everything seems to be in order, but embryo implantation fails, possibly due to a diminished embryo quality. However 60-70% of these couples will still get pregnant within 3 years.

The figure below shows the ovulation and the descent and implantation of the embryo.

Endometriosis

Endometriosis is in 6% the reason for reduced fertility. With endometriosis menstrual tissue can be found outside the uterus. This can in severe cases result in adhessions of the Fallopian tubes which may lead to a reduced functioning of these tubes. The endometriosis tissue can also be present in the ovaries, where the ovaria cavity may fill up with (old) menstrual blood, called endometriotic cystes.

This figure shows an uterus and ovaries with endometriosis and Fallopian tubes with adhesions.