Surface changes in intrauterine contraceptive devices after variable use.

Four used intrauterine contraceptive devices and two new control devices were studied by scanning electron microscopy. All intrauterine contraceptive devices were found to have surface deposits that differed not only from site to site on a given device but between devices. A finding of this study not previously described in the literature was the observation of a euhedral crystal rosette of an apatite mineral group [Ca5(PO4)3(F,Cl,OH)] on the Lippes Loop that had been in situ for 15 years.