Experimental Nonsurgical Female Sterilization: Transcervical Implantation of Microspindles in Fallopian Tubes

A nonsurgical method of female sterilization was investigated in rabbits. A self-expanding microspindle (length 9–18 mm, diameter 1.5–2.0 mm) made from tubular metal mesh was implanted in a single fallopian tube of 12 rabbits via catheterization of a single uterus. The contralateral fallopian tube and uterus served as controls. Each rabbit was scheduled to undergo three cycles of breeding. Before delivery, absence of pregnancy on the side with the microspindle was verified with hysterography. Eight rabbits completed three cycles of breeding and pregnancy. Two rabbits had one pregnancy. Two rabbits did not conceive. Spindles were placed correctly in 11 rabbits. Successful contraception was achieved in nine rabbits, who had 25 gestations on the nonspindle side and no gestation on the spindle side. One rabbit, which received the shortest spindle, was bilaterally pregnant, indicating a failure of contraception on the spindle side. No spindles dislocated. Histologic study showed all spindles firmly embedded in the tubal wall without signs of inflammation. Microspindles of a certain minimum length have potential as a transcervically implantable, permanent intratubal contraceptive device.