Filshie clips, small titanium-and-silicone implants used for female sterilization, can detach from the fallopian tubes and move elsewhere in the abdomen, potentially causing pain. An investigation by Trouw found that patients in the Netherlands are not adequately informed about that risk by Entercare, the Dutch company that sells the clips.

The clips have been used since the 1980s and were for years among the most common methods of female sterilization because they are effective and relatively easy to place. During the procedure, one clip is clamped onto each fallopian tube, preventing fertilization. Even if a clip later moves elsewhere in the body, pregnancy generally remains prevented because the tissue of the fallopian tube has already died.

The possibility that the clips can migrate is known to the manufacturer, Femcare. The company provides information about the risk in English-language patient materials on its website. That warning, however, is absent from the information provided by Entercare, which sells the clips in the Netherlands.

As a distributor, Entercare is required to ensure that translated product information is complete and current. After questions from Trouw, the company said its information would soon “be brought into line with the most recent patient information approved by the manufacturer.”

The frequency of clip migration and the extent to which it causes symptoms remain uncertain because there has been limited research. In the study conducted by the manufacturer for market authorization, fewer than one in 1,000 women experienced migration. The study followed 5,454 women who had undergone sterilization for up to two years.

In that study, three women expelled the clips from their bodies, including cases in which a clip passed through the ureter. In another three women, clips were found incidentally in different locations in the body without causing symptoms. Femcare estimates that about 25% of clips eventually migrate, usually without causing problems.

That 25% figure is an estimate, however, and pain can develop many years after the procedure. One woman interviewed by Trouw developed severe pain in her side four years after the clips were implanted. Doctors found that the clips had moved to a location near her kidney. Medical literature also contains cases of women who developed symptoms from migrated clips 10 years or more after sterilization.

“There is no high rate shown by the research that has been conducted, but there has not been much research,” said Bas Veersema, an emeritus professor of gynecology. The clips are also not systematically registered, which may make it difficult to identify pain or other problems associated with them. “If the clips migrate only years later, the connection between the symptoms and the clips also becomes much less clear.”

Gynecologist and sterilization specialist Andreas Thurkow said many doctors are also unaware of the migration risk. As a result, women may not receive complete information before choosing the procedure and may encounter skepticism if they later develop symptoms.

“They are told that it cannot be caused by the clips,” Thurkow told Trouw. “Ultimately, we have to leave the choice to the woman, but only after she has been informed of all the pros and cons.”

Femcare said the Filshie clips meet the safety requirements applicable in the European Union. The company described complications following migration as “extremely rare.” Apart from its own study, which followed patients for up to two years after sterilization, Femcare said its assessment is based on clinical experience, case reports from gynecologists, and reports from health care professionals and patients worldwide. The company confirmed that, to its knowledge, no other clinical research has been conducted.

An estimated tens of thousands of women in the Netherlands have been sterilized using Filshie clips. Thurkow estimates that he has removed the clips from about 50 women who experienced pain. Veersema puts his estimate closer to 10 women. Both doctors said that the clips had migrated in some of these patients and that the women’s symptoms disappeared after the clips were removed.

The two gynecologists are calling for better implant registration. “We should continue monitoring what happens for much longer, and we need to take patients with symptoms seriously,” Thurkow said.

The latest Dutch medical guideline now recommends removal of the fallopian tubes as the preferred sterilization method because it reduces the risk of cancer. Filshie clips, however, are still being used. Entercare said about 700 sets of the clips are sold in the Netherlands each year. It is not known how many of those sets are actually used.

The Dutch Adverse Effects and Implants Expertise Center, where patients and health care professionals have been able to report implant-related adverse effects since 2017, has received 12 reports involving Filshie clips. A spokesperson said those reports do not provide grounds for an investigation.