What hormones are in NuvaRing (etonogestrel and ethinyl estradiol)?

NuvaRing Hormonal Composition

NuvaRing contains two hormones: etonogestrel (a progestin) at 120 μg per day and ethinyl estradiol (an estrogen) at 15 μg per day. 1

Specific Hormone Details

• Etonogestrel: This is the active metabolite of desogestrel and serves as the progestational component of the contraceptive ring 1, 2
• Ethinyl estradiol: This is the estrogenic component, delivered at a lower daily dose (15 μg) compared to most combined oral contraceptives which typically contain 20-35 μg 1

Mechanism of Hormone Delivery

• The ring releases these hormones continuously through the vaginal epithelium over a 3-week period, avoiding the daily fluctuations in serum levels typically seen with oral contraceptives 3, 4
• Each ring is designed for single-cycle use: 3 weeks of continuous vaginal placement followed by 1 week ring-free to allow withdrawal bleeding 1, 2

Pharmacokinetic Advantages

• The vaginal route of administration provides more stable hormone levels compared to oral contraceptives 3, 4
• Maximum serum levels of ethinyl estradiol with NuvaRing are approximately 30% of those achieved with a 30 μg oral contraceptive pill, resulting in half the total estrogen exposure while maintaining comparable progestin exposure 4
• This lower estrogen exposure may contribute to fewer estrogen-related side effects such as nausea (2.8%) and breast tenderness (1.9%) 2

Clinical Efficacy

• These hormone doses provide robust ovulation inhibition with a Pearl Index of 0.65, demonstrating high contraceptive efficacy comparable to combined oral contraceptives 2, 3
• The ring maintains complete ovulation suppression even with extended use up to 5 weeks 4