Saltatory Pattern of Fetal Heart Rate during Labor Is a Sign of Fetal Hypoxia

BACKGROUND: While late decelerations and major bradycardia episodes in intrapartum cardiotocography (CTG) recordings are known to correlate with fetal distress,little is known of the importance of the saltatory pattern. OBJECTIVE: The aim of the study was to examine whether the fetal heart rate (FHR) saltatory pattern in intrapartum CTG registration is associated with fetal hypoxia during the last 2 h of labor. DESIGN: The study group consisted of CTG recordings from 194 births with a 1-min Apgar score of <8 (birth weight 3,614 ± 512 g; gestational age 40.6 ± 0.7 weeks). The comparison group included 51 infants with a 1-min Apgar score of ≥9 (birth weight 3,624 ± 400 g; gestational age 40.5 ± 0.4 weeks). FHR patterns were evaluated blindly by 2 experienced perinatologists. The pH, base excess (BE), pO2 and erythropoietin (EPO) were measured from umbilical cord blood at birth as outcome variables. RESULTS: Saltatory pattern occurred in 31/194 (16.0%) of the study group and in 1/51 (2.0%) of the comparison group. Umbilical artery pH, BE, and pO2 were lower and umbilical vein (UV) EPO higher in the study group than in the comparison group. In the study group, UV EPO level was significantly higher in cases where the saltatory pattern was present (median 241 mU/mL, 95% CI 39.4-16,484), than in those without the saltatory pattern (median 39.4 mU/mL, 95% CI 11-282) (p < 0.0001, for difference). In the study group, no differences in EPO levels were found in cases where episodes of bradycardia, tachycardia, reduced variability, or uterine tachysystole were present or absent. In the study group, saltatory pattern preceded late decelerations in 82.8%. CONCLUSION: Saltatory pattern in an intrapartum FHR recording is an early sign of fetal hypoxia.