The Pearl Index (PI) is defined as the number of pregnancies per 100 women years. The 3-year PI (Years 6 to 8) was obtained by dividing the number of pregnancies the occurred during that time (starting at Day 1 Year 6 and up to Day 365 of Year 8) by the time (in 100 women years) that the women were at risk of getting pregnant during that time.

All women in the full analysis set (FAS) with an age of 33 years or younger at baseline visit (i.e. an age of 36 or younger at end of year 8).

Menstrual blood loss (MBL) during a 30-day period starting at the baseline visit and at the end of Year 6, Year 7, and Year 8, measured by the alkaline hematin method. The assessment of this variable was restricted to women who had Mirena inserted for heavy menstrual bleeding (HMB).

Women who had Mirena inserted for HMB

Categorized menstrual blood loss (MBL) (≥ 80 mL per 30 days) at end of Year 6, Year 7, and Year 8. The assessment of this variable was restricted to women who had Mirena inserted for HMB.

Women who had Mirena inserted for HMB

Adverse event (AE) was defined as any untoward medical occurrence (ie any unfavorable and unintended sign [including abnormal laboratory findings], symptom or disease) in a patient or clinical investigation subject after providing written informed consent for participation in the study. Serious adverse event (SAE) was defined as any untoward medical occurrence that, at any dose 1) resulted in death, 2) was life-threatening, 3) required inpatient hospitalization or prolongation of existing hospitalization, 4) resulted in persistent or significant disability/incapacity, 5) was a congenital anomaly/birth defect, or 6) was another medically important serious event as judged by the investigator. Treatment-emergent adverse event (TEAE) was defined as an AE that occurred on Day 1 Year 6 of Mirena use or later.

Safety analysis set (SAF): All women who completed the baseline visit of the study, analyzed for the FAS.

A population pharmacokinetic (popPK) analysis was performed including sparse data from the study.

Concentrations were estimated for women who had Mirena still in place.

Participants were asked to evaluate their satisfaction with Mirena on a 5-point scale as very satisfied, somewhat satisfied, neither satisfied or dissatisfied, dissatisfied or very dissatisfied.

Full analysis set (FAS): All women who completed the baseline visit of the study.