The plan is therefore to take transvaginal, ultrasound-guided biopsy-samples from the uterus (myometrium) of all included patients at the beginning of their surgery, when the patient is under full anesthesia. The safety of comparable procedures has been shown in prior studies, but the investigators will further validate the safety of this method. The investigators believe that an in-vivo biopsy is a safe measure, and that representative samples of adenomyosis can be obtained.