Silvia Azaña, an embryologist at inviTRA, explains in this video what female infertility due to tubal factor refers to:
The fallopian tubes must be permeable and have the ability to move to carry out their function correctly. Their function consists of picking up the egg released by the ovary, allowing it to meet with the sperm and fertilization to occur, and finally transporting the embryo to the uterus, where it must implant to lead to pregnancy. Therefore, the function of the fallopian tubes is essential for a natural pregnancy to occur.
In this way, tubal factor refers to alterations in the fallopian tubes that hinder or even prevent pregnancy.
Sometimes a woman only presents with a unilateral tubal factor, meaning only one of the tubes is affected and the other is healthy. In this case, a natural pregnancy can occur, although the chances of achieving it may be reduced, thus lengthening the time it takes.
When the tubal factor is bilateral, both tubes are damaged. Therefore, natural pregnancy is not possible, as the meeting between egg and sperm is prevented. A patient with bilateral tubal involvement will generally have to resort to assisted reproduction if she wishes to be a mother.
