A cervical transfer catheter (10) for transferring a therapeutic substance to an endocervix or other internal mucosal surfaces of a recipient, the catheter (10) comprising: a catheter body (12) having first and second lumens (14) and (16), the second lumen (16) being adapted, in use, to allow passage and retention of a structure containing the therapeutic substance that will be released slowly and continuously. The catheter (10) also comprises an inflatable balloon (20) provided at a distal end of the first lumen (14), the inflatable balloon (20) being designed to be as small as possible in its inflated condition while still being retained in the uterus by virtue of its shape.