Finally an explanation for the many side effects of Essure contraceptive implants? This spring-shaped sterilization implant placed at the level of the fallopian tubes was placed in nearly 200,000 French women between 2002 and 2017. Nearly a thousand of them have already reported side effects.

According to researchers and doctors from the mineralogical analysis company Minapath, a defective tin solder could be the cause of these gynecological (pelvic pain, urinary disorders, pain during sexual intercourse, etc.) and systemic (fatigue, memory impairment, visual disturbances, headaches, etc.).

18 new cases analyzed

Their work, made public on December 22, should be quickly published in a scientific journal. They confirm a previous research published in April 2020 in theEuropean Journal of Obstetrics & Gynecology which was based on the case of 10 explanted women and which already pointed out a possible effect of tin.

In this new study, the cases of 18 new patients aged 36 to 56 were analyzed. These women were all implanted with the Essure device and then explanted by hysterectomy (removal of the uterus) and salpingectomy (removal of the tubes) to relieve the side effects they reported. They had kept their implants between 44 and 178 months, or approximately between 3.5 and 15 years.

Read also: Essure implants: removing them to improve women’s health?

Tin particles and inflammation of the uterus

Result: in 17 of these 18 patients, granulomas, that is to say clusters of cells indicating inflammation, were detected in the tubes. And in all the uteruses analyzed, tin-based particles were found. “These particles are embedded in the tissue, often at the level of the wall, generally in the form of clusters“write the researchers in their publication.

What can we learn from this? As the inflammation is not limited to the tubes but spreads to the horns and the lining of the uterus, the researchers recommend not to be limited to the withdrawal of the tubes in the event of an explant, but to “always perform a hysterectomy with salpingectomy“.

A “vastly underestimated” risk

But how to explain the presence of tin in the uterus of patients? The Essure implant includes an internal stainless steel spring and an external Nitinol (titanium and nickel) spring to help hold the implant in the tube. The two springs are linked by a tin solder. A defect in this weld or its wear could lead to the dissemination of tin particles in the uterine tissues.

Through chemical reactions, these particles could themselves evolve into more toxic particles, organotin, the researchers suggest. And all the symptoms described by the patients coincide, according to the specialists, with “chronic organotin poisoning“.

For them, “toxic risk estimation“tin solder was therefore”largely underestimated in the implant corrosion tests carried out in 2004. “

The safety profile remains “favorable” according to Bayer

Contacted by on December 24, the Bayer laboratory which manufactured and marketed these implants confirmed having been informed of this new study. But “Bayer cannot comment on its conclusions as it did not participate in the study and was not aware of all the results.“, specified the press service.

The laboratory also ensures that “women currently carriers“implants”can continue to use this device” and “Essure’s favorable safety profile remains unchanged“.

Continue research

On December 17, the Ministry of Health announced the upcoming establishment of a register of explanted women to better monitor side effects.

At the same time, Minapath experts plan to continue their work on a larger number of women to confirm the tin hypothesis. An assay of tin in the blood of patients should in particular make it possible to shed light on the biological mechanisms of possible intoxication.