What is female sterility?
The World Health Organisation has redefined the concept of sterility defining sterile not only those individuals affected by pathologies that limit fertility but also anyone that has had targeted and unprotected sex for 12 months without procreating. Primary sterility is when a couple has never been able to conceive while secondary sterility is when a couple has previously conceived. Sterility in couples is instead when it is related to the combined characteristics of the couple. The causes of female sterility are multiple, like anatomical, hormonal, genetic and infectious.
What are the possible anatomical causes?
Anatomical causes that can determine female sterility are damages to the Fallopian tubes that can be partial in case of adherences caused by surgery or total if the tubes are completely closed. In both cases, the movement of the egg is impeded, therefore making its fertilization impossible. Alterations to the tubes can also cause extrauterine pregnancies in which the embryo does not develop inside the uterine cavity like in normal situations, leading to an early interruption of pregnancy. Endometriosis can also lead to female sterility; 35% of sterile women are affected by endometriosis because the abnormal presence of endometrium in organs different from the uterus can cause the obstruction of the tubes or the formation of ovarian cysts. Polycystic ovary syndrome, characterised by irregular or absent menstrual cycles, with consequent absence of ovulation, can also lead to sterility problems. Among the other risk factors there are myoma and fibroids that are essentially an excessive and abnormal proliferation of the cells of the uterus that cause vascular modifications that alter uterine contractility negatively, influencing the progression of sperm, the transportation of the oocyte and its implantation. Together with this there is also a rare anatomical condition known as “unicornuate uterus” in which the uterus is smaller than normal, with only one tube and one ovary. This condition causes a lack of development of the foetus therefore increasing the risk of sterility in women.