A vacuum extractor for obstetrical use comprises a vacuum cup at one end of an elongated stem having a handle at the opposite end. The vacuum cup is sealed over a portion of the head of the fetus and a vacuum source, usually operating through the stem, connects to the inner side of the cup and secures it to the fetal head. A strain sensor is connected to the stem. When the force applied to the cup through the handle and stem exceeds a predetermined maximum, a valve connecting the vacuum pressure to the atmosphere is opened so as to release the vacuum pressure from the cup. Another extractor comprises an elongated stem and a traction limiter having one or more apertures, a vacuum source connected to a cup supported on the stem, and a handle member in arrangement with the traction limiter operative to open and close the apertures.
