The U.S. Food and Drug Administration is stepping in to tighten the rules on surgical mesh devices, which have been the subject of scores of class action lawsuits lately due to complications.

Surgical mesh devices are used to repair pelvic organ prolapse (POP) via the vagina, which happens when the muscles and tissue of the pelvic floor get stretched or weakened and can’t support pelvic organs, resulting in prolapse, according to a Reuters report.

The FDA is responding to thousands of complaints of complications, urinary problems, organ perforation, and bleeding stemming from the meshes. They have been used since the 1950s to repair abdominal hernias, and were used for repair of POP by the 1970s.

But concerns about their safety have caused regulators to revisit surgical meshes and more closely scrutinize their safety.

The amount of lawsuits stemming from surgical mesh complications has been staggering. Boston Scientific Corp. and a number of other manufacturers have faced a total of 100,000 lawsuits. The lawsuits claim that the meshes were design poorly with bad materials, resulting in terrible side effects that can cause permanent damage to the body.

The FDA will be requiring manufacturers to submit an application that demonstrates that their surgical meshes are safe and effective, especially when it comes to POP. Those that are already producing surgical meshes for POP will have 30 months to submit an application, whereas those who are making new meshes will need to submit the application before they can market the device.