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

Inclusion Criteria:

• Not diagnosed with perimenopause or menopause.

• Heterosexually active with a partner who is not known to be subfertile, sterilized,or infertile, and is seeking contraception for pregnancy.

• Palpable intact ENG implant in the upper inner-arm for 36 months from the date ofinsertion at the time of enrollment, and has documentation of the insertion date (for example, Nexplanon user card or medical record completed on the date ofinsertion).

• Does not desire a pregnancy within the 24 months after enrollment, is willing tocontinue use of the implant for an additional 24 months, and is not intending to useany other form of contraception (eg, condoms) from enrollment until after implantremoval at 24 months post enrollment.

• Good physical and mental health in the medical judgment of the investigator.

• History of regular menstrual cycles of 21 to 35 days before the insertion of the ENGimplant or before hormonal contraceptive use (which may have preceded the currentimplant use).

• Able and willing to adhere to all required study procedures, including study visitsand eDiary entries, and not planning to relocate during the study.

Exclusion Criteria:

• Conceived a pregnancy during use of the current implant or a past contraceptiveimplant.

• Known or suspected pregnancy at the time of screening or enrollment visit.

• History of subfertility or infertility.

• Breastfeeding.

• Untreated gonorrhea, chlamydia, or trichomonas or symptomatic vaginitis/cervicitis.

• Significantly abnormal cervical cytology (Pap) or pathology results either atscreening or documented in the 36-month period prior to enrollment.

• Current use of an intrauterine device/intrauterine system (IUD/IUS).

• Presence of more than one ENG implant.

• Use of daily/monthly hormonal contraceptives, sex steroids, or GnRHagonist/antagonist within 3 months prior to enrollment.

• Use of injectable hormonal contraceptive with 3-month duration within 9 months priorto enrollment.

• Use of injectable GnRH agonist with 3-month duration within 10 months prior toenrollment .

• Use of medications that induce liver enzymes within 2 months prior to enrollment.

• Untreated or unresolved vaginal bleeding or spotting attributable to underlyingpathology in the 12 months before screening.

• Frequent, prolonged, or excessive vaginal bleeding/spotting in the 12 months priorto screening which has not been evaluated to detect underlying pathology.

• History of venous thromboembolism or arterial thromboembolism, transient ischemicattack, angina pectoris, or claudication.

• Any condition associated with an increased risk of venous thromboembolism.

• Uncontrolled or severe hypertension at screening visit.

• Clinically significant liver disease, including active viral hepatitis or cirrhosis.

• History of malignancy within 5 years before screening, except treated skin cancer.

• History of sex steroid-influenced malignancies (eg, genital organs, breasts).

• History or presence of liver tumors (benign or malignant).

• Known allergy/sensitivity or contraindication to the ENG implant or lidocaine withepinephrine.

• History of drug or alcohol abuse or dependence within 24 months prior to enrollment.Routine use of alcohol or marijuana that is not considered abuse or dependence isnot exclusionary.

• Use of an investigational drug within 2 months prior to enrollment. Long-term followup of an investigational compound for COVID-19 is allowed 2 months after the lastadministered dose.

• Staff or immediate family members of the investigational site or Sponsor directlyinvolved with this study.