A multicentre efficacy and safety study of the single contraceptive implant Implanon

• Published in: Human reproduction (Oxford) 1999-04, Vol.14 (4), p.976-981
• Main Authors: Croxatto, Horacio B., Urbancsek, János, Massai, Rebeca, Bennink, Herjan Coelingh, van Beek, Agaath, the Implanon® Study Group
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Birth control; contraceptive implant; efficacy; Gynecology. Andrology. Obstetrics; Implanon®?; Medical sciences; Other methods of contraception. Sterilization; safety; vaginal bleeding
• ISSN: 0268-1161; 1460-2350; 1460-2350
• DOI: 10.1093/humrep/14.4.976

An open, multicentre study was performed to assess efficacy, safety and acceptability of the single-rod contraceptive implant Implanon®. The study involved 635 young healthy women, who were sexually active and of childbearing potential. The women were followed up every 3 months over the entire study period. Originally the study was designed for 2 years, but was extended to 3 years in a group of 147 women from two centres. Altogether, 21 centres in nine different countries participated. The average age of the women was 29 years (range 18–42 years), of whom 83.5% had been pregnant in the past. No pregnancy occurred during treatment with Implanon®, resulting in a Pearl Index of 0 (95% confidence interval: 0.0–0.2). In the first 2 years, 31% had discontinued the treatment. Of the 147 women in the study extension, nine discontinued (6%) treatment. Bleeding irregularities was the main reason for discontinuation during the first 2 years of use (17.2%) and adverse experiences in the third year (3.4%). Implant insertion and removal were fast and uncomplicated in the vast majority (97%) of cases. Return of fertility was prompt. In conclusion, Implanon® has excellent contraceptive action during its lifetime of 3 years. The safety profile is acceptable and not essentially different from progestogens in general.