a period of three months, resulting in blockage in the Fallopian tubes; the tissue barrier formed is supposed to prevent sperm from reaching an egg. During that intervening three-month period, women are advised to use an alternate contraceptive method. Unlike tubal ligation, it may not require a general anaesthetic (though is often done under general anaesthetic). Despite this, some women have reported considerable pain during the procedure. In one 2007 prospective study, the mean time for procedure was 6.8 minutes (range = 5–18 minutes) for a trained physician to perform. The procedure can be performed in a physician's office. The procedure is reported to be permanent and not reversible by the manufacturer. Nevertheless, several Essure reversals have been performed. Device The small, flexible inserts are made from polyester fibers, nickel-titanium, stainless steel and solder. The insert contains inner polyethylene terephthalate fibers to induce inflammation, causing a benign fibrotic ingrowth, and is held in place by flexible stainless steel inner coil and a dynamic outer nickel titanium alloy coil. Unlike temporary methods of birth control, the Essure inserts do not contain or release hormones. The inserts do not prevent the transmission of sexually transmitted infections. Regulatory history A Facebook group called Essure Problems which had 33,140 members (as of 04/03/2017) called the method "E-hell" and mentioned mostly pain, bleeding, bloating and other side effects from the device. Some women had coils break and perforate their internal organs, or conceived and gave birth to a child, at a number well above what Bayer has been reporting. Erin Brockovich became involved in the controversy and hosts a website where women can share their stories after having the procedure. Since then Bayer provided two toll-free telephone numbers for patient complaints, has advised that women reporting adverse effects are "consistent with clinical trials and consistent with what the FDA is seeing", and further insisted that it wanted to hear from any women experiencing problems with Essure. In April 2015, a group of six delegates from the Essure Problems group, including a doctor with Essure experience, spoke before 36 members of the FDA and the Congressional HELP committee regarding a citizen's petition filed with the FDA. The FDA began investigating the claims of then over 16,000 members of the group as well as the legalities of the approval process that Essure went through. As of 2015, one postmarketing study was not published for 13 years after