An improved fetal pulse oximeter sensor. The friction provided on the sensor head surface to engage the fetus is higher than the friction on the back side of the sensor head. Thus, any contact with a maternal surface by the back side of the sensor head is less likely to dislodge the sensor, since the maternal tissues will slide over the sensor head. The portion of the sensor surface in contact with the fetus' head will not move because of the increased friction. The increased friction can be achieved by using two different materials with different coefficients of friction, or by using a smooth surface on the back of the sensor head, and a rough surface on the sensor face.