Contraceptive transcervical fallopian tube occlusion devices

The invention provides an intrafallopian device to prevent conception. The efficacy of the device (10) is enhanced by forming the structure at least in part from copper or a copper alloy. The device (10) is anchored within the fallopian tube by a lumen-traversing region of the resilient structure which has a helical outer surface, together with a portion of the resilient structure which is biased to form a bent secondary shape, the secondary shape having a larger cross section than the fallopian tube. The resilient structure is restrained in a straight configuration and transcervically inserted within the fallopian tube, where it is released. Optionally, permanent sterilisation is effected by passing a current through the resilient structure to the tubal walls. A device further includes openings between an inner and outer surface to allow for in-growth of tissue.