title: Pathologic fetal acidemia.
abstract: There is no clearly established umbilical artery pH cutoff to be used for defining pathologic fetal acidemia (ie, the threshold associated with major neonatal morbidity or mortality). Classically, a pH cutoff of less than 7.20 has been used. Our goal was to define this pH cutoff more precisely. There were 3506 term newborns (2500 g or greater) with an umbilical artery pH of less than 7.20; these newborns were divided into five pH groups. Eighty-seven (2.5%) had a pH of less than 7.00, 95 (2.7%) a pH of 7.00-7.04, 290 (8.3%) 7.05-7.09, 798 (22.8%) 7.10-7.14, and 2236 (63.8%) 7.15-7.19. Two-thirds (66.7%) of the newborns with an umbilical artery pH less than 7.00 had a metabolic component in their acidemia, compared with 13.7% or less in all other pH groups. Significantly more (P less than .05) newborns in the less-than-7.00 pH group had low (less than 3) 1- and 5-minute Apgar scores compared with the other four pH groups. In addition, neonatal death was significantly more common (P = .03) in newborns with a pH less than 7.00, and seven (50%) of the 14 deaths occurred in this group. The statistically significant pH cutoff for all seizures was less than 7.05 (P = .004), and for unexplained seizures was less than 7.00 (P = .01). Eight (67%) of the 12 unexplained seizures occurred in this latter pH group. Thus, a more realistic pH cutoff for defining pathologic fetal acidemia would appear to be less than 7.00.
authors.affiliation: Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas.
authors.forename: K G
authors.initials: KG
authors.lastname: Goldaber
authors.forename: L C
authors.initials: LC
authors.lastname: Gilstrap
authors.forename: K J
authors.initials: KJ
authors.lastname: Leveno
authors.forename: J S
authors.initials: JS
authors.lastname: Dax
authors.forename: D D
authors.initials: DD
authors.lastname: McIntire
mesh_terms: D000138:Acidosis / Q000097:blood* / Q000401:mortality; D001034:Apgar Score; D005260:Female; D005315:Fetal Diseases / Q000097:blood*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007231:Infant, Newborn; D007744:Obstetric Labor Complications / Q000209:etiology; D011247:Pregnancy; D012640:Seizures / Q000209:etiology