Initial UK experience of the levonorgestrel-releasing contraceptive intravaginal ring

A study was performed to establish the tolerance, acceptability and associated efficacy of a levonorgestrel-releasing intravaginal ring (IVR) in a sample of British women requiring contraception. This was achieved with an open non-randomized prospective study of 1710 women aged 18-40 years, recruited in 75 centers geographically spread around the UK using an IVR designed to release 20 microg/day of levonorgestrel. Assessments were made at baseline, after 6 weeks, after 3 months and then 3-monthly. After initial insertion of the IVR, it was changed at 3-monthly intervals. A total of 1591 women were eligible for analysis, with 572 available after 12 months and 34 after 24 months of use. Life-table analysis revealed pregnancy rates of 5.1% and 6.5% at 12 months and 24 months, respectively. The IVR was rated as acceptable or very acceptable as a form of contraceptive by 60.7% of women at 12 months. The most common adverse events were menstrual disturbance, headache and vaginal discharge. No significant pattern of biochemical, hematological, microbiological or cytological abnormalities was found but vaginal erythematous lesions were noted at some centers. This IVR was found to be a generally well-accepted method of contraception with a failure rate comparable to some other progestogenonly methods. On this basis, further development of hormone-releasing intravaginal rings is justified.