Caesarean Scar Defect (CSD) is defined as the presence of a “niche” at the site of a Caesarean delivery scar site.
With the rising rate of caesarean section, prevalence of CSD is between 24% and 70% in a random population of women with at least one Caesarean delivery.
The issue arises when the defect becomes a pouch, or isthmocele in the lower uterine segment and accumulates fluid or blood. When old menstrual blood becomes trapped in the isthmocele and uterine cavity, it sets up an inflammatory response in the uterus impairing embryo implantation.
It is postulated that accumulated blood in the niche can ultimately degrade cervical mucus and sperm function, as well as inhibit sperm transport, a proposed mechanism of infertility.