Indicators of umbilical arterial blood acid-base status during spontaneous labor and cesarean section

Objective. To comparatively analyze the data on the umbilical arterial blood acid-base status in healthy newborn infants according to the method of delivery. Subjects and methods. The prospective examination covered the results of umbilical arterial blood (UCAB) gas analysis in 280 healthy newborns: 152 babies after spontaneous labor, 62 after cesarean section (CS) before the beginning of delivery, and 66 after CS during labor for reasons unrelated to hypoxia. Results. The mean umbilical arterial blood pH value during spontaneous labor was 7.28 (0.09) and was significantly lower than that in patients undergoing CS before delivery (7.34 (0.06) (p <0.001)). The base deficiency level during spontaneous labor was 7.4 (3.1) versus 2.8 (1.7) mmol/L in those undergoing CS before labor and 5.9 (3.0) during labor (p = 0.007). The level of lactate during spontaneous labor was 5.4 (2.0) and was much higher than in CS before delivery (2.1 (0.8)) and during labor (2.8 (1.9)) (p = 0, 0007). The partial pressure of carbon dioxide and oxygen was not different. Conclusion. The findings showed significant differences in the UCAB acid-base status after labor and CS done before the beginning of delivery. These differences must be considered when evaluating the status of a newborn infant. Even the clinically healthy newborns have a wide range of fluctuations in pH values, base deficiency, and cord blood lactate after both labor and CS. In some observations, there is a mismatch between cardiotocographic data at the birth, the satisfactory status of newborn health, and changes in the UCAB acid-base status.

pH, labor, cesarean section, hypoxia, acidosis, acid-base status, pH, lactate, base deficiency