How does menstruation after annulus go about uncoordinated

Irregular menstruation after the ring is because the intrauterine device will produce mechanical compression on the uterus, which is not conducive to the growth of the endometrium, which easily leads to endometrial ischemia and necrosis, thus leading to irregular menstruation. Usually, it will gradually adapt after three months of placement, and the symptoms can be alleviated.