We aim to explore some of the molecular factors that reduce fertility for women with leiomyomas, taking into account leiomyoma location, size, number and vascularity. Tissue samples from the endometrium and leiomyomas will be obtained during the mid secretory phase before and 3-6 months after surgical excision for a comprehensive search for key molecular derangements.

Baseline medical information and standard questionnaire to record symptoms are collected from all participants and a gynaecological examination and a 2D and 3D vaginal ultrasonography including saline infusion sonography (SIS), if indicated, are performed. Blood samples for the biobank for extraction of germ line DNA and for identification of possible biomarkers are taken.

The women with submucosal leiomyomas will undergo hysteroscopic myomectomy and the women with intramural leiomyomas will undergo myomectomy per laparoscopy or laparotomy.

For the participants with intramural leiomyomas and the fertile/infertile controls, endometrial samples are taken with an endometrial suction curette in an outpatient setting at day 19-23 of the menstrual cycle. The endometrial sampling in the group of women with submucosal leiomyomas is being done during the hysteroscopic removal of the leiomyoma, also at day 19-23 of the menstrual cycle.

3-6 months after surgery, cycle day 19-23, endometrial samples will be taken from the women who have undergone myomectomy and ultrasound examination is being performed. The women with submucosal leiomyomas will undergo a second look hysteroscopy

Inclusion Criteria:

• Age: 18 to 40 years
• Presence of leiomyoma(s)
• Regular menstrual cycle (28 +/- 7 days)
• Having had at least 2 normal menstrual cycles after ending the treatment if previously treated with GnRH analogue
• Signed informed consent

Exclusion Criteria:

• No treatment indication (no symptoms and/or no desire for fertility)
• Contraindication for surgery
• Known endometriosis
• Known PCOS
• Untreated hydrosalpinx
• Malignancy; gynaecological or other location
• Pre-malignant or malignant pap smear or endometrial biopsy
• Hormonal treatment including ulipristal acetat and levonorgestrel intrauterine device last three months before inclusion in the study
• Ongoing treatment with GnRH analogue
• Pregnancy last 3 months
• Ongoing lactation

The biological sex must be female since we are studying a phenomenone occuring in the female genital tract.

Patients referred to the Department of Gynaecology at Oslo University Hospital for treatment of submucosal or intramural leiomyomas.