New research confirms efficacy of NuvaRing

By David Archer, MD and Susan Ballagh, MD
CONRAD
Department of Obstetrics and Gynecology
Eastern Virginia Medical School
Norfolk

Since the NuvaRing contraceptive vaginal ring (Organon, West Orange, NJ) entered the U.S. market in mid-2002, new research has been published that underscores its efficacy and acceptability. Clinicians will need to review this data to better inform patients in their contraceptive counseling sessions.

A multicenter clinical trial, using the ethinyl estradiol (EE)/etonogestrel (ETG) vaginal ring, has shown high levels of efficacy with an overall Pearl Index of 0.65 per 100 women years of use.1 This clinical finding of contraceptive efficacy is confirmed in studies in which ovarian function has been assessed using transvaginal ultrasound along with serum levels of follicle-stimulating hormone (FSH), estradiol, and progesterone.2,3 These pharmacodynamic studies have shown inhibition of follicular development with resultant low levels of estradiol, suppressed levels of FSH, and no evidence of ovulation based on serum progesterone levels.

A unique study was carried out that showed that after one month of use of the ring, reinsertion of the ring for three days or three weeks resulted in continued ovarian inhibition during the period of time of ring use, but when the vaginal ring was removed after three days or three weeks, there was a similar rapid reinitiation of follicular development.4 The average interval between the removal of the ring and maximum follicular development was approximately 11 days.4 These data highlight the fact that there is a rapid return of ovarian function with removal of the contraceptive vaginal ring.

Menstrual cycle control is an important aspect of steroidal contraception to the patient and the provider. The cycle control with the EE/ETG vaginal ring has been excellent.5,6 Unlike oral contraceptives that improve with use, fewer than 5% of women will have bleeding with NuvaRing right from the start. Based on the definition of withdrawal bleeding, the incidence of intended withdrawal bleeding after removal of the ring was approximately 70% of all cycles.5,6 In contrast, using the same definition for a combination oral contraceptive, the incidence of intended withdrawal bleeding was less than 50% in all cycles.5,6

The reason for this excellent cycle control is not clearly known at the present time, but may be due to:

  • consistent, stable levels of the hormone in blood in woment using the ring;
  • higher compliance with the use of the ring (one insertion and removal per month) compared to daily pill intake for 21 days.

The principal reproductive side effect with the vaginal ring has been vaginal discharge.1 This may be a welcome change for some women. There was no significant change in cervical cytology (Papanicoulaou smear) with the use of the vaginal contraceptive ring, and the Nugent score to document bacterial vaginosis was unchanged (Archer DF, Darney P, Alexander N unpublished observations).

As for drug interactions, the NuvaRing package insert states that use of a vaginal fungicidal preparation, miconazole nitrate, with the NuvaRing increases the serum levels of ethinyl estradiol and etonogestrel. The concomitant vaginal use of the spermicide nonoxynol-9 did not change absorption of EE or ETG in 12 subjects.7 These findings suggest that these vaginal products may be used with the ring.

Acceptability in clinical trials has been high with more than 90% of the women reporting a positive experience and 97% indicating they would recommend the vaginal contraceptive ring to others.8 Few patients or partners feel the ring interferes with coital activity. Few couples remove it for coitus:

  • 85% of the women and 71% of their partners never or rarely felt the ring during intercourse;8,9
  • 94% of the partners never or rarely minded that their partner used the ring.9

It should be stressed that the ring may be removed for intercourse and then reinserted afterward. The actual interval of removal that would reduce contraceptive efficacy is not known. The manufacturer states in the package insert that if the ring is out for more than three hours, backup contraception should be used until the vaginal ring has been back in place for seven days. Based on the observed return of ovarian function after removal of the vaginal ring, it may take several days before significant follicular development occurs.4 This finding suggests continued contraceptive efficacy is likely, even if the removal interval is six to eight hours.

References

1. Roumen F. Contraceptive efficacy and tolerability with a novel combined contraceptive vaginal ring, NuvaRing. Eur J Contracept Reprod Health Care 2002; 7 Suppl 2:19-24; discussion 37-39.

2. Killick S. Complete and robust ovulation inhibition with NuvaRing. Eur J Contracept Reprod Health Care 2002; 7 Suppl 2:13-8; discussion 37-39.

3. Mulders TM, Dieben TO. Use of the novel combined contraceptive vaginal ring NuvaRing for ovulation inhibition. Fertil Steril 2001; 75:865-870.

4. Mulders TM, Dieben TO, Bennink HJ. Ovarian function with a novel combined contraceptive vaginal ring. Hum Reprod 2002; 17:2,594-2,599.

5. Vree M. Lower hormone dosage with improved cycle control. Eur J Contracept Reprod Health Care 2002; 7 Suppl 2:25-30; discussion 37-39.

6. Bjarnadottir RI, Tuppurainen M, Killick SR. Comparison of cycle control with a combined contraceptive vaginal ring and oral levonorgestrel/ethinyl estradiol. Am J Obstet Gynecol 2002; 186:389-395.

7. Haring T, Mulders TM. The combined contraceptive ring NuvaRing and spermicide co-medication. Contraception 2003; 67:271-272.

8. Szarewski A. High acceptability and satisfaction with NuvaRing use. Eur J Contracept Reprod Health Care 2002; 7 Suppl 2:31-36; discussion 37-39.

9. Novak A, de la Loge C, Abetz L, et al. The combined contraceptive vaginal ring, NuvaRing(R): An international study of user acceptability. Contraception 2003; 67:187-194.