An integrated introducer and drive rod system used to position and attach a spiral-shaped, biological needle probe to a fetus during labor and delivery. The system ensures that the sharp, pointed, probe (typically, a fetal spiral electrode) remains protected in a retracted position inside the introducer until attachment to the fetal scalp is desired. The flexible drive rod of the system has a "C"-shaped safety ring with an outside diameter slightly less than the inner diameter of the introducer at a point on the introducer; a "C"-shaped radial web with an outside diameter only slightly larger than the inner diameter of the introducer creating an interference fit between the drive rod and the introducer; or a "C"-shaped segmented rib that engages the rear end of the introducer. The introducer has an inner diameter sized to create an interference fit with the drive rod; a forward interior wall with an inside diameter slightly less than the outside diameter of the safety ring; a ramp on the front end of the introducer; a longitudinal slot disposed along its entire length; or a combination of one or more of these structures. In combination, the structures of the drive rod and introducer resist but (upon exertion of a predetermined force on the handle of the drive rod) allow translation of the drive rod within the introducer.