From the Guidelines
The Nova ring releases 120 μg of etonogestrel and 15 μg of ethinyl estradiol daily. This vaginal contraceptive ring is used for 21 consecutive days, followed by a 7-day ring-free period before inserting a new ring 1. The hormones work by preventing ovulation, thickening cervical mucus to block sperm, and thinning the uterine lining to prevent implantation. Some key points to consider when using the Nova ring include:
- The daily hormone release rates are considered low-dose compared to many oral contraceptives, which may result in fewer systemic side effects while still providing effective contraception 1.
- The ring maintains steady hormone levels throughout the day, unlike pills which can cause daily fluctuations.
- Users should be aware that the ring must be inserted and removed on the same day of the week to maintain effectiveness, and a backup method should be used for the first seven days when starting the ring for the first time. It's also important to note that the Nova ring, like other combined hormonal contraceptives, carries a mild increase in stroke risk, as indicated in the 2024 guideline for the primary prevention of stroke 1. However, the overall effectiveness of the Nova ring in preventing pregnancy is high, with a contraceptive effectiveness of 93-97% 1.
From the FDA Drug Label
The serum etonogestrel and ethinyl estradiol concentrations observed during three weeks of NuvaRing® use are summarized in Table I. TABLE I: MEAN (SD) SERUM ETONOGESTREL AND ETHINYL ESTRADIOL CONCENTRATIONS (n=16). 1 week 2 weeks 3 weeks etonogestrel(pg/mL) 1578 (408) 1476 (362) 1374 (328) ethinyl estradiol(pg/mL) 19.1 (4.5) 18.3 (4.3) 17.6 (4.3)
The hormone levels of the Nova ring are:
- Etonogestrel: 1374-1578 pg/mL
- Ethinyl estradiol: 17.6-19.1 pg/mL 2
From the Research
Nova Ring Hormone Levels
The Nova ring, also known as NuvaRing, is a combined contraceptive vaginal ring that releases hormones to prevent pregnancy. The hormone levels of the Nova ring are:
Mechanism of Action
The Nova ring works by inhibiting ovulation, thereby preventing pregnancy. It is inserted into the vagina for 3 weeks, followed by a 1-week ring-free period.
Efficacy and Safety
The efficacy and safety of the Nova ring have been studied in several clinical trials. The Pearl index, which measures the number of pregnancies per 100 woman-years, has been reported to be around 0.65-1.18 3, 4, 5. The most common adverse events associated with the Nova ring include:
Comparison with Other Contraceptives
The Nova ring has been compared with other combined hormonal contraceptives, such as oral contraceptives, and has been found to have similar efficacy and adverse event profiles 4. However, the Nova ring may offer advantages in terms of convenience and ease of use, as it requires less frequent dosing and can be self-administered 7.