Abstract: Described herein is an apparatus to detect fetal acidosis during labor. This apparatus, which is noninvasive to the fetus, has a pH sensor and at least one fetal tissue detector. When the apparatus is inserted into the vaginal canal of a patient during labor, the pH reading determined by the pH sensor correlates to the pH of the fetus's blood. The fetal tissue detector may be a pulse oximeter, which may allow for a user to obtain the pulse rate reading of a surface contacted by the pH sensor. This pulse rate reading may be compared to an external reading of a pulse rate of the patient to confirm whether the pH sensor is contacting the fetus. During travel through the vaginal canal, the pH sensor may be protected by a protective sheath with an area of weakness to allow exposure of the pH sensor when the fetus is reached.