A Study to Assess Contraceptive Efficacy and Safety of Etonogestrel (ENG) Implant Beyond 3 Years of Use (MK-8415-060)

Pearl Index will be calculated as the number of on-treatment pregnancies per 100 woman-years of exposure. Exposure in 100 woman-years is equal to the number of cycles of use/1300, and one woman-year is defined as a period of 13 treatment cycles, each 28 days long. Only "at risk" cycles for conception will be included in this Pearl Index calculation. An at risk cycle is defined as a cycle during which participants with ENG implant had affirmed heterosexual intercourse without the use of additional contraception.

Pearl Index will be calculated as the number of on-treatment pregnancies per 100 woman-years of exposure. Exposure in 100 woman-years is equal to the number of cycles of use/1300, and one woman-year is defined as a period of 13 treatment cycles, each 28 days long. Only "at risk" cycles for conception will be included in this Pearl Index calculation. An at risk cycle is defined as a cycle during which participants with ENG implant had affirmed heterosexual intercourse without the use of additional contraception.

Cumulative on-treatment pregnancy rate will be calculated based on life table analysis over 5 years of implant use.

Cumulative on-treatment pregnancy rate will be calculated based on life table analysis over 4 years of implant use.

Pearl Index will be calculated as the number of on-treatment pregnancies per 100 woman-years of exposure. Exposure in 100 woman-years is equal to the number of cycles of use/1300, and one woman-year is defined as a period of 13 treatment cycles, each 28 days long. Only "at risk" cycles for conception will be included in this Pearl Index calculation. An at risk cycle is defined as a cycle during which participants with ENG implant had affirmed heterosexual intercourse without the use of additional contraception. The number of at-risk cycles of use for each of the 3 years prior to study entry will be estimated.

Pearl Index will be calculated as the number of on-treatment pregnancies per 100 woman-years of exposure. Exposure in 100 woman-years is equal to the number of cycles of use/1300, and one woman-year is defined as a period of 13 treatment cycles, each 28 days long. Only "alternative at risk" cycles will be included in this Pearl Index calculation. An alternative at risk cycle is defined as a cycle in which participants with ENG implant did not use additional contraception, but without the requirement for affirmed heterosexual intercourse. The number of alternative at risk cycles of use for each of the 3 years prior to study entry will be estimated.

Participants will record daily vaginal bleeding in an electronic diary. A bleeding day is defined as any day (24 hours) with bloody vaginal discharge requiring more than one sanitary product (i.e., pad, panty liner, tampon, or menstrual cup) or, if only a menstrual cup is used, more than 5 mL of blood accumulates. Number of bleeding days will be assessed per 90-day reference period (RP).

Participants will record daily vaginal spotting in an electronic diary. A spotting day is defined as any day (24 hours) with bloody vaginal discharge requiring at most one sanitary product (i.e. pad, panty liner, tampon, or menstrual cup containing 5 ml [inclusive] or less of blood). Number of spotting days will be assessed per 90-day reference period (RP).

Participants will record daily vaginal bleeding and/or spotting in an electronic diary. A bleeding day is defined as any day (24 hours) with bloody vaginal discharge requiring more than one sanitary product (i.e., pad, panty liner, tampon, or menstrual cup) or, if only a menstrual cup is used, more than 5 mL of blood accumulates. A spotting day is defined as any day (24 hours) with bloody vaginal discharge requiring at most one sanitary product (i.e. pad, panty liner, tampon, or menstrual cup containing 5 ml [inclusive] or less of blood). Number of bleeding and/or spotting days will be assessed per 90-day reference period (RP).

Participants will record daily vaginal bleeding and/or spotting in an electronic diary (eDiary). A bleeding day is defined as any day (24 hours) with bloody vaginal discharge requiring more than one sanitary product (i.e., pad, panty liner, tampon, or menstrual cup) or, if only a menstrual cup is used, more than 5 mL of blood accumulates. A spotting day is defined as any day (24 hours) with bloody vaginal discharge requiring at most one sanitary product (i.e. pad, panty liner, tampon, or menstrual cup containing 5 ml [inclusive] or less of blood). A bleeding and/or spotting episode is defined as one or more consecutive days during which bleeding and/or spotting is recorded in the eDiary, bounded bleeding/spotting-free days.

Participants will record daily vaginal bleeding and/or spotting in an electronic diary (eDiary). Amenorrhea is defined as no bleeding or spotting recorded in the eDiary per 90-day reference period (RP).

Participants will record daily vaginal bleeding and/or spotting in an electronic diary (eDiary). A bleeding day is defined as any day (24 hours) with bloody vaginal discharge requiring more than one sanitary product (i.e., pad, panty liner, tampon, or menstrual cup) or, if only a menstrual cup is used, more than 5 mL of blood accumulates. A spotting day is defined as any day (24 hours) with bloody vaginal discharge requiring at most one sanitary product (i.e. pad, panty liner, tampon, or menstrual cup containing 5 ml [inclusive] or less of blood). Infrequent bleeding and/or spotting is defined as less than 3 episodes of bleeding and/or spotting per 90-day reference period (RP).

Participants will record daily vaginal bleeding and/or spotting in an electronic diary (eDiary). A bleeding day is defined as any day (24 hours) with bloody vaginal discharge requiring more than one sanitary product (i.e., pad, panty liner, tampon, or menstrual cup) or, if only a menstrual cup is used, more than 5 mL of blood accumulates. A spotting day is defined as any day (24 hours) with bloody vaginal discharge requiring at most one sanitary product (i.e. pad, panty liner, tampon, or menstrual cup containing 5 ml [inclusive] or less of blood). Frequent bleeding and/or spotting is defined as more than 5 episodes of bleeding and/or spotting per 90-day reference period (RP).

Participants will record daily vaginal bleeding and/or spotting in an electronic diary (eDiary). A bleeding day is defined as any day (24 hours) with bloody vaginal discharge requiring more than one sanitary product (i.e., pad, panty liner, tampon, or menstrual cup) or, if only a menstrual cup is used, more than 5 mL of blood accumulates. A spotting day is defined as any day (24 hours) with bloody vaginal discharge requiring at most one sanitary product (i.e. pad, panty liner, tampon, or menstrual cup containing 5 ml [inclusive] or less of blood). Normal frequency of bleeding and/or spotting is defined as 3 to 5 episodes of bleeding and/or spotting per 90-day reference period (RP).

Participants will record daily vaginal bleeding and/or spotting in an electronic diary (eDiary). A bleeding day is defined as any day (24 hours) with bloody vaginal discharge requiring more than one sanitary product (i.e., pad, panty liner, tampon, or menstrual cup) or, if only a menstrual cup is used, more than 5 mL of blood accumulates. A spotting day is defined as any day (24 hours) with bloody vaginal discharge requiring at most one sanitary product (i.e. pad, panty liner, tampon, or menstrual cup containing 5 ml [inclusive] or less of blood). Prolonged bleeding and/or spotting is defined more than 14 continuous days of bleeding and/or spotting, per 90-day reference period (RP).

Complications associated with implant removal will include failed implant removal; implant site fibrosis; extension of incision of >1 cm; removal of a nonpalpable implant; removal of a deeply placed implant; implant removal in an operating room; implant removal requiring general anesthesia; implant removal requiring regional anesthesia; implant removal requiring imaging guidance; nerve injury during implant removal; vascular injury during implant removal; other complications of device removal not previously mentioned.