Clinical testing has shown that the Essure procedure:

• Is 99.80% effective in preventing pregnancy based on four years of follow-up
• Can be performed in about 10 minutes without incisions or general anaesthesia
• Provides for a rapid recovery
• Has a high patient satisfaction rating

Phase 1A - Placement feasibility of micro-inserts

In this early clinical trial, micro-inserts were placed in patients immediately before a planned hysterectomy, which was previously planned for medical purposes. These patients never relied on the micro-inserts for contraception, but evidence was obtained that micro-inserts could be safely placed in the fallopian tubes.

Phase 1B - Placement feasibility and comfort of micro-inserts

In this second clinical trial, patients had micro-inserts placed up to 30 weeks before planned hysterectomies, so they never relied on the micro-inserts for contraception. After the hysterectomy, the tubes containing micro-inserts were examined under a microscope by an independent specialist. The specialist found that the tissue response to the micro-inserts caused the tubes to be blocked, preventing sperm from reaching the egg. Additionally, this clinical trial provided evidence that micro-inserts could be safely placed in patients who were awake, and women were comfortable with micro-inserts in their fallopian tubes.

Phase II Study - Preliminary safely and effectiveness

The Phase 1A and 1B clinical trials, discussed above, showed that micro-inserts could be safely placed into fallopian tubes and were well tolerated by women. The Phase II Study was conducted to learn about the effectiveness and long-term use of the Essure system. The study involved about 200 women seeking permanent contraception from the United States, Europe, and Australia. This study provided evidence that the Essure procedure was effective and well tolerated by women. This data supported testing in a larger group of women.

Pivotal Trial - Safety and effectiveness

Based on the positive results obtained from earlier clinical trials, a Pivotal Trial of the Essure procedure was conducted in about 450 women from the United States, Europe, and Australia.

Results from the Phase II and the Pivotal trials showed:

• Essure is 99.80% effective based on four years of follow-up.
• Almost all women employed outside the home returned to work 24 hours or less after the procedure
• Almost all women rated their comfort as "good" to "excellent" within one week of the procedure
• Almost all women rated their satisfaction with the Essure procedure as "somewhat satisfied" to "very satisfied" after the one-week visit
• Essure received its CE mark in 2001. It remains the only contraceptive method with zero pregnancies in clinical trials