The purpose of this study is to assess the efficacy, safety, bleeding pattern of low dose LNG (12 mg/ 24 hrs), delivered locally by a new intrauterine contraceptive system suitable for use by women 18 to 40 years of age. In addition, pharmacokinetic assessments will be performed.

Inclusion Criteria:

• Has, in the opinion of the investigator, suitable general and uterine conditions for inserting the LCS.
• Normal cervical smear (normal cervical smear within the last six months prior to visit 1 presented in writing can be accepted. The cervical smear should be analyzed and reported according to the Bethesda System.)
• Has clinically normal safety laboratory results (i.e., inside the specified range for inclusion).
• Has regular menstrual cycles (length of cycle 21-35 days) (i.e., endogenous cyclicity without hormonal contraceptive use).

Exclusion Criteria:

• Known or suspected pregnancy or is lactating.
• Vaginal delivery, cesarean delivery, or abortion within 6 weeks prior to visit 2.

Note: Postpartum insertions should be postponed until uterus is fully involuted, however not earlier than 6 weeks after delivery. If involution is substantially delayed, consider waiting until 12 weeks postpartum. In case of a difficult insertion and/or exceptional pain or bleeding during or after insertion, physical examination and ultrasound should be performed immediately to exclude perforation.

• History of ectopic pregnancies. Note: For Korea only: History of ectopic pregnancies or high probability of ectopic gestation.
• Infected abortion within 3 months prior to visit 1. Note: For Korea only: Endometritis after delivery or infected abortion within 3 months prior to visit 1.
• Abnormal uterine bleeding of unknown origin.
• Any genital infection (until successfully treated).
• History of, or current, pelvic inflammatory disease
• Congenital or acquired uterine anomaly.
• Any distortion of the uterine cavity (by e.g., fibroids) likely to cause problems (in the opinion of the investigator) during insertion, retention or removal of the LCS.
• History of, diagnosed or suspected genital malignancy, and untreated cervical dysplasia.
• Current deep venous thrombosis or thrombophlebitis; history of deep venous thrombosis.
• Clinically significant endometrial polyp(s), which, in the opinion of the investigator, will interfere with the assessment of the bleeding profile during the study
• Clinically significant ovarian cyst(s)
• Use of any long-acting injectable sex-hormone preparations within 12 months prior to start of study medication, and if entering subset: any sex-hormone administration within one month prior to start of the study medication.