Fetal pulse oximetry during labor of 62 patients.

The objectives of the study were to assess the ability of a fetal pulse oximeter to measure the fetal oxygen saturation (SPO2) continuously during labor and to assess the correlation between readings of fetal pulse oximetry and cord blood gases at birth. The Nellcor N-400 Fetal Oximeter was used in 62 women prospectively. The mean SPO2 was unchanged at the different stages of normal labor. 53.3 +/- 9.1 to 50.1 +/- 11.8% (n = 50). The SPO2 recorded during the pushing phase of stage II (n = 40) was correlated significantly with umbilical cord arterial pH (r = 0.55; p = 0.0002), venous pH (r = 0.63; p = 0.0001), venous PCO2 (r = 0.47; p = 0.002) and venous PO2 (r = 0.39; p = 0.01). SPO2 was also correlated with scalp pH (r = 0.52; p < 0.05; n = 21). No side effects were noted. Fetal pulse oximetry could be useful to assess fetal oxygenation during labor and at birth.