Fetal pulse oximetry and fetal heart rate monitoring during stage II of labour.

Objective: This study was designed to assess the changes in fetal oxygen saturation (FSpO2) using fetal pulse oximetry when the fetal heart rate (FHR) monitoring became abnormal during stage II of labour.

Study Design: FSpO2 was recorded with the Nellcor N400 Oximeter (FS-14 sensor) and was averaged over the last 10 min of the second stage of labour. Second stage FHR patterns were assessed according to Melchior's classification.

Results: In terms of FHR patterns, FSpO2-10" measured 41.4% in type 0 (n = 5), 42.4% in type 1 (n = 19), 43.3% in type 2 (n = 6), 34.0% in type 3 (n = 4) and 27.6% in type 4 (n = 7) (P = 0.03).

Conclusions: FSpO2-10" decreases in cases of severe FHR abnormality during the second stage of labour and could help to decide whether to perform an instrumental extraction.