What is the dosing schedule for the Annovera (segesterone acetate 0.013 mg/24 h and ethinyl estradiol 0.15 mg/24 h) vaginal ring?

Annovera Dosing Schedule

Annovera is used in a 21-days-in/7-days-out regimen for up to 13 consecutive cycles (one full year), with the same ring inserted vaginally for 21 days followed by a 7-day ring-free interval when withdrawal bleeding typically occurs. 1, 2

Standard Dosing Regimen

• Insert one Annovera ring into the vagina for 21 consecutive days 1, 3, 2
• Remove the ring for 7 days (hormone-free interval), during which withdrawal bleeding typically occurs 1, 2
• Reinsert the same ring after the 7-day ring-free period to begin the next cycle 3, 2
• Continue this 21-days-in/7-days-out pattern for up to 13 cycles (364 days total) using the same single ring 1, 3, 2

Key Dosing Details

• The ring releases segesterone acetate 0.15 mg/day and ethinyl estradiol 0.013 mg/day 1, 4
• One ring provides contraception for an entire year without need for monthly refills or clinic visits 2, 4
• The ring should be stored at room temperature between cycles during the 7-day ring-free intervals 3

Critical Usage Instructions

• Any ring removals during the 21-day use period should not exceed 2 hours to maintain contraceptive efficacy 2
• If the ring is removed for <48 hours: reinsert as soon as possible, keep the ring in until the scheduled removal day, and no additional contraceptive protection is needed 5
• If the ring is removed for ≥48 hours: reinsert as soon as possible, use backup contraception (condoms) or avoid intercourse until the ring has been worn for 7 consecutive days, and consider emergency contraception if removal occurred during the first week of use with unprotected intercourse in the previous 5 days 5

Common Pitfalls to Avoid

• Unscheduled ring removals increase the risk of contraceptive failure 1
• Women should use daily paper diaries to track ring use and ensure proper timing of insertion and removal 2
• Counsel patients before initiation about potential unscheduled spotting or bleeding, especially during the first 3-6 months, which is generally not harmful and decreases with continued use 5
• The hormone-free interval should not be extended beyond 7 days as this increases pregnancy risk 5

Efficacy Considerations

• The Pearl Index is 2.98 per 100 woman-years with Kaplan-Meier analysis showing 97.5% effectiveness 2
• Pregnancy occurrence is similar across all 13 cycles, indicating consistent efficacy throughout the year of use 2
• Limited efficacy and safety data exist for patients with BMI >29 kg/m², so clinicians should carefully consider whether Annovera is appropriate for obese patients if other acceptable alternatives exist 6