Correspondence

Volume 162 Number 4

Intrapartum fetal asphyxia To the Editors: The article by Dr. Low regarding the biochemical diagnosis of intrapartum fetal asphyxia (Low JA. The role of blood gas and acid-base assessment in the diagnosis of intrapartum fetal asphyxia. AM J OBSTET GYNECOL 1988; 159: 1235-40) has profound clinical and medicolegal implications. A metabolic acidosis on a fetal scalp capillary sample or in umbilical cord blood is usually regarded as evidence of intrapartum asphyxia. As reported by Dr. Low, however, clinical evidence of fetal distress in labor, such as meconium staining of the amniotic fluid or fetal heart rate abnormalities, is only occasionally associated with fetal acidosis. This has also been the experience in 6646 patients delivered in this hospital in 1987 1 : 350 cases (5.3%) required fetal scalp sampling in labor for meconiumstained amniotic fluid or fetal heart rate abnormalities. Only 13 of the 142 cases (9.2%) with meconium-stained fluid and 22 of the 208 cases (10.6%) with fetal heart rate abnormalities had an acidotic fetal scalp sample (pH