The cause of<unk>  is unknown, although it has been associated with any sort of uterine trauma that may break the barrier between the endometrium and myometrium, known as the junctional zone, such as a caesarean section, surgical pregnancy termination, and any pregnancy. It can be linked with endometriosis, but studies looking into similarities and differences between these two conditions have conflicting results. The pathogenesis of<unk>  still remains unclear, but the functioning of the inner myometrium, also called the junction zone (JZ), is believed to play a major role in the development of<unk> . It is also a matter of discussion whether the link between reproductive disorders and major obstetrical disorders also lies here. Parity, age, and previous uterine abrasion increase the risk of<unk> . Hormonal factors such as local hyperestrogenism and elevated levels of s-prolactin as well as autoimmune factors have also been identified as possible risk factors. As both the myometrium and stroma in an<unk>  affected uterus show significant differences from those of a non-affected uterus, a complex origin that includes multifactorial changes on both genetic and biochemical levels is likely. The tissue injury and repair (TIAR) theory is now widely accepted and suggests that uterine hyperperistalsis (i.e., increased peristalsis), during early periods of reproductive life will induce micro-injury at the endometrial-myometrial interface (EMI) region. That again leads to elevation of local estrogen in order to heal the damage. At the same time, estrogen treatment will increase uterine peristalsis again, leading to a vicious circle and a chain of biological alterations essential for the development of<unk> . Iatrogenic injury of the junctional zone or physiological damages due to placental implantation most likely results in the same pathological cascade. This also explains that<unk>  often gets more severe after each pregnancy and childbirth, while endometriosis will ameliorate.
Adenomyosis
Endometrial polyp
Leiomyoma
Endometrial hyperplasia
Cervical pregnancy
Endometriosis
Uterine fibroid
Endometrial intraepithelial neoplasia