[Fetal pulse oximetry in second stage of labor]

To compare the mean values of fetal oxygen saturation with fetal heart rate pattern in the second stage of labor (Melchior classification)

The study included 30 parturients in gestational age 37-41 weeks. Fetal oxygen saturation was recorded and averaged over the last 30 min of the second stage of labor Simultaneously, fetal heart rate and uterine contractions were monitoring. Fetal heart rate patterns were assessed according to Melchior's classification. At birth, the cord acid-base parameter (pH) was calculated.

The lowest value of fetal oxygen saturation over the last 30 min of labor was 10%, the highest 60%, and the mean value 39.1 +/- 12.5%. Statistically, significant correlation between the mean value of oxygen saturation over the last 30 min of labor and pH arterial values (n = 25, p = 0.004, r = 0.42) was found. There was no statistically significant correlation between fetal oxygen saturation and pH venous values (n = 24, p. = 0.006, r = 0.49), but trend towards significance could be observed. Statistical analysis revealed that arterial pH was significantly correlated to Melchior's classification. The lowest pH and FSpO2 values coexisted with type 3 and 4 of FHR patterns according to Melchior's classification.

The mean values of fetal oxygen saturation over the last 30 min of labor significantly correlate with arterial pH values. These values correlate with FHR abnormalities according to Melchior's classification. Fetal pulse oximetry seems to be an important, additional method assessing fetal well-being in the second stage of labor.