Acidosis in newborns with nuchal cords and normal Apgar scores.

Objective: Apgar scores and cord blood gases (BG) and pH were compared between a group of babies with nuchal cords and a group without nuchal cords and uncomplicated deliveries.

Study Design: We collected umbilical arterial (UA) and umbilical venous (UV) blood samples from the placentas of term infants from both normal deliveries (NORM, n=29) and nuchal cords (NUCH, n=33). BG/pH and hematocrit were measured; base deficits and oxygen contents were calculated; and a member of the study assigned Apgar scores and demographic data were collected from the babies' charts.

Results: Median Apgar scores in the NUCH babies at 1 and 5 minutes were 9 and 9 respectively, which did not differ from the NORM infants. The pH, PCO(2), and oxygen content obtained from UV of the NUCH infants was not statistically different from the NORM. The pH and oxygen content of the NUCH UA was significantly lower than that of the NORM. The UA PCO(2) in the NUCH was greater than the NORM. Veno-arterial (VA) differences (Delta VA) in pH and PCO(2) of the NUCH infants were greater than that of the NORM.

Conclusion: The Apgar score is not a sensitive indicator of acid-base changes in nuchal cord patients; UV samples alone may be misleading. UA must be sampled to detect the hypercapnia and diminished oxygen content that is a result of the nuchal cord.