The “E-Sisters” were able to start the conversation, but even with their harrowing stories, it is hard to say just how risky Essure really is. And that’s the actual problem: We don’t know enough about Essure to quantify the hazards — and these unknowns have persisted since the beginning, with some experts arguing the device never should have been approved in the first place.As patient complaints have increased, experts like Charles Monteith, MD, a North Carolina-based surgeon and Sanket Dhruva, MD, a postdoctoral fellow at Yale University , have gone back and looked at the science behind the approval of the Essure device. Their conclusions are startling: They say that there were flaws with the two studies that supported the FDA’s approval of the device all the way back in 2002.Dr. Monteith, medical director of A Personal Choice Tubal Reversal Center, says that the pre-approval studies for Essure did not measure the risk for long-term health complications, only the risk for complications early on. In his opinion this boils down to “running an uncontrolled trial on American women as a result of the decisions that were made when the device was approved.”The studies included data from a total of 745 women followed for five years after getting Essure. None of the women became pregnant, and adverse events “that prevented reliance on Essure for contraception” were observed in 9% of women in one study and 2.6% of the women in the second study. These included instances of perforation, expulsion of the coils from the fallopian tubes, and misplacement. Still, since no pregnancies occurred in the first study and at the five-year follow-up, Essure was deemed a successful preventative permanent birth control and was approved by the FDA.Dr. Dhruva, whose research focuses on medical decision-making, including FDA approvals, published a paper in the New England Journal of Medicine in October that looked back at the possible flaws in the pre- and post-approval study results of Essure. (Post-approval studies are common and meant to examine the results from pre-approval studies of medical devices once they’re on the market.) He found that the studies didn’t compare results against the current method of sterilization, the tubal ligation, and in fact, most of the women in the original studies weren’t even followed for the full five years. Of the 745 women included in the studies that led to the approval of Essure, only 197 were still being followed after two years.On top of that, Dr. Dhruva writes that FDA approval was conditional on the publication of post-approval studies, but that those have flaws as well. One is still ongoing almost 14 years after approval, and another, which enrolled 518 women and followed them for five years, neglected to include those women whose placements were unsuccessful, or who underwent hysterectomy within that time, in the effectiveness analysis.Without accounting for every person in the studies, and without including a control group who received the alternative, tubal ligation, the medical community has a difficult time assessing the true risks and benefits associated with Essure, Dr. Dhruva says.An ideal study would take a tubal ligation group and an Essure group, follow them for at least five years, and compare the endpoint results (bleeding, unintended pregnancies, hysterectomies, and so on). “Once enrolled, you always follow. That’s an obligation taught in medical school,” Dr. Dhruva says, conceding that “it can be difficult to follow every patient,” but it’s “the goal.”The bottom line: The limited data on Essure’s effectiveness points to “inflated success rates and deflated failure rates,” adds Aileen Gariepy, MD, a Yale Ob/Gyn who worked on the study with Dr. Dhruva.Following that hard-won hearing, the FDA announced in February several new requirements , including new product labeling, and a “Patient Checklist” designed to help physicians improve their methods of explaining the device’s risks to patients. Most notably, the FDA has ordered Bayer to conduct a new study investigating the device's safety — although the device remains on the market.The FDA, for its part, has been receiving reports about Essure-related problems since it was approved through its Manufacturer and User Facility Device Experience database, or MAUDE for short. The database is available for manufacturers, physicians, patients, and consumers of medical devices to report adverse events, such as injuries, malfunctions, or death. The reports are mandatory for manufacturers and voluntary for consumers, patients, and healthcare professionals. Depending on the severity of a case, the FDA may choose to investigate further, but confirming the reports is difficult, especially in the case of Essure.The number of reports may be increasing due to media attention and the growth of the Essure Problems Facebook group. By the FDA’s count, between November 2002 and December 31, 2015, the MAUDE database received 9,900 reported incidents related to the Essure device, including 26 reported deaths. Most of these were voluntary reports made by Essure patients, the FDA says on its website