Inclusion Criteria:
* 1\. Healthy, post-menarcheal and premenopausal women of age 18 to 35 years (inclusive) at screening examination.
2\. BMI ≥18.0 kg/m2 at screening examination. 3. Participants must be in good physical and mental health as determined by vital signs, medical history, and physical and gynecological examination, as assessed by the investigator.
4\. Written informed consent, after having been informed about benefits and potential risks of the clinical trial, as well as details of the insurance taken out to cover the participant participating in the clinical trial.
5\. Status at least 3 months after a delivery, abortion, and stopping lactation, if applicable, before screening.
6\. Has regular menstrual cycles that are between 21 and 35 days in duration as reported by the participant during anamnesis, with an intact uterus and ovaries. If the participant uses hormonal birth control at screening, historic data should be used to evaluate this criterion.
7\. Both ovaries must be visible on TVUS examination during screening. 8. Ovulatory pre-treatment cycle, as confirmed by a progesterone concentration \>10.0 nmol/L.
9\. Participants must consent to use reliable non-hormonal contraceptive methods (male condoms, diaphragm, or heterosexual abstinence) throughout the study, unless the participant has a history of female sterilization or sterilization of the sexual partner.
Exclusion Criteria:
* 1\. Known hypersensitivity or intolerance to any ingredient of the investigational product.
2\. History or presence of dermal sensitivity to medicated patches or to topical applications including bandages, surgical tape.
3\. Pregnancy or a positive serum beta human chorionic gonadotropin (β-hCG) pregnancy test at screening.
4\. Clinically relevant abnormal findings from serum biochemistry and hematology and HBsAG/ Hepatitis C virus/ human immunodeficiency virus (HIV) serology as evaluated by the investigator 5. ASAT (aspartate-aminotransferase) \> 20 % upper limit of normal (ULN), ALAT (alanine-aminotransferase) \> 10 % ULN, bilirubin \> 20% ULN (except in case of existing Morbus Gilbert-Meulengracht deduced from anamnesis/medical history) and creatinine \> 0.1 mg/dL ULN (limit of \> 0.1 mg/dL corresponds to \> 9 µmol/l ULN).
6\. Use of a non-hormonal intra-uterine device within the pre-treatment cycle or any hormonal contraception as follows:
* Short-acting hormonal contraceptives such as oral, patch, ring or intrauterine systems within the menstrual cycle prior to the pre-treatment cycle.
* Injectable (intramuscularly or subcutaneously) within 10 months (three-month treatment duration), 6 months (two-month treatment duration) or 3 months (one-month treatment duration) prior to the start of pre-treatment cycle or implants within the menstrual cycle prior to the pre-treatment cycle.
7\. Known or suspected malignancy or history thereof. 8. Unexplained vaginal bleeding within the past 6 months suspicious for serious condition, or any abnormal bleeding which is expected to recur during the study (e.g. bleeding from cervical polyp, recurrent bleeding after sex).
9\. History or presence of ischemic heart disease, coronary artery disease, myocardial infarction, stroke, other cerebrovascular diseases including transient ischemic attacks (TIAs).
10\. History or presence of hypertension or hypertension with vascular disease or elevated blood pressure (BP) defined as systolic BP ≥140 mm Hg or diastolic BP ≥90 mm Hg, measured in sitting position after at least 5 minutes of rest (a single reading of blood pressure level is not sufficient to classify a woman as hypertensive).
11\. Pulse rate (PR) \< 50 bpm or \> 90 bpm 12. Presence of deep vein thrombosis/pulmonary embolism. 13. Has any comorbid condition that may require major surgery with prolonged immobilization during the study period.
14\. Presence of liver disease including severe (decompensated) cirrhosis, benign (e.g., hepatocellular adenoma) or malignant liver tumors.
15\. Chronic disease potentially necessitating organ transplantation during the anticipated course of the study.
