Fetal blood saturation during the 1st and 2nd stage of labor and its relation to the neonatal outcome

Gynecol Obstet Invest. 2002;54(3):159-63. doi: 10.1159/000067884.

Abstract

Objective: The aim of this study was to evaluate fetal blood oxygenation (SpO(2)) by means of continuous pulse oximetry during labor and its relation to the neonatal outcome.

Materials and methods: Fetal SpO(2) was measured continuously during labor with a noninvasive pulse oximetry for fetal application. The average, minimum and maximum SpO(2) levels were evaluated separately for the 1st and 2nd stage of labor. The average SpO(2) of the fetus was compared to the neonatal outcome assessed by the levels of pH, pO(2) and pCO(2) in the fetus' umbilical blood and to the Apgar score.

Results: Twenty-eight patients were monitored by fetal pulse oximetry. All the patients had normal, vaginal delivery. During the 1st stage of labor, the average fetal SpO(2) was 51.78 +/- 8.00%, the minimum SpO(2) level was 37.61 +/- 9.86%, and the maximum level of SpO(2) was 63.82 +/- 7.37%; in the 2nd stage of labor, the average SpO(2) level was 44.91 +/- 8.28%, the minimum level was 35.00 +/- 9.22%, and the maximum SpO(2) was 52.30 +/- 9.36%. A significant decrease in the fetal average and maximum SpO(2) levels was observed between the 1st and the 2nd stages of labor (the average SpO(2) was 51.78 +/- 8.00% vs. 44.91 +/- 8.28%, p = 0.00029; the maximum SpO(2) was 63.82 +/- 7.37% vs. 52.30 +/- 9.36%, p < 0.00001). A significant correlation between the average SpO(2) level during the 1st and 2nd stage of labor and the Apgar score at the first minute of outcome was observed (R = 0.43, p = 0.031). No relationship between the fetal SpO(2) during the 1st and the 2nd stage of labor and the pH, pCO(2), and pO(2) in the fetal umbilical blood were observed.

Conclusions: During the 2nd stage of labor, a significant decrease in the fetus' SpO(2) can be observed. The fetus' SpO(2) level >30% in the 1st and 2nd stage of labor was related to the good neonatal outcome. The assessment of the fetal SpO(2) during the 1st stage of labor seems to be important in predicting neonatal outcome.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Apgar Score
  • Carbon Dioxide / blood
  • Female
  • Fetal Blood / metabolism
  • Fetal Monitoring / methods*
  • Fetus / metabolism*
  • Humans
  • Hydrogen-Ion Concentration
  • Hypoxia / prevention & control
  • Infant, Newborn
  • Labor Stage, First / physiology
  • Labor Stage, Second / physiology
  • Oximetry / methods*
  • Oxygen / blood*
  • Predictive Value of Tests
  • Pregnancy
  • Pregnancy Outcome
  • Prenatal Diagnosis / standards*

Substances

  • Carbon Dioxide
  • Oxygen