Risk, Predictors, Impact and Outcome of Anticoagulation-associated Abnormal Menstrual Bleeding

Inclusion Criteria: 1. Ability of subject to understand the character and individual consequences of this clinical study; 2. Signed and dated informed consent of the subject available before the start of any specific study procedures; 3. Age ≥18 years and ≤ 50 years; 4. Confirmed symptomatic first or recurrent VTE; 1. DVT: incompressibility of proximal or distal veins of the affected leg by compression ultrasonography or venous filling defect on multi-detector computed tomography venography. The diagnosis of ipsilateral recurrent DVT is defined as a CUS that shows incompressibility of a different venous segment than at the reference CUS examination, or in case of a pronounced increase in vein diameter (≥4 mm) of a previous non-compressible venous segment, or by an abnormal signal of Magnetic resonance direct thrombus imaging (MRDTI); 2. PE: both first and recurrent PE are diagnosed in case of at least one filling defect in the pulmonary artery tree on multi-detector computed tomography pulmonary angiography (CTPA) up to the subsegmental level, or high probability result of ventilation perfusion scintigraphy; 5. Childbearing potential, i.e. with active menstrual cycle with or without hormonal regulation of any kind initiated for reasons of either contraception or for treatment of abnormal menstrual bleeding; 6. Inclusion before the first day of next menstrual cycle after VTE diagnosis or within 1 month after the VTE diagnosis, whichever comes first. Exclusion Criteria: 1. Woman between the ages of 18 and 50 who were subjected to hysterectomy or chemically induced menopause; 2. Woman between the ages of 18 and 50 with premature menopause (established before study inclusion); 3. Planned treatment with parenteral anticoagulation (and no switch to oral drugs); 4. Medical or psychological condition that would not permit completion of the study or signing of informed consent, including life expectancy less than 6 months, or unwillingness to sign informed consent; 5. Non-compliance or inability to adhere to the follow-up visits; 6. Pregnancy or post-partum (first three months) associated VTE; 7. Active in vitro fertilization (IVF) treatment or planned IVF treatment during the study period.