The presence of a ZigZag fetal heart rate pattern or late decelerations during the last 2 hours of labor was associated with cord blood acidemia (OR 3.3; 95% CI 2.3-4.7).
Cohort (n=4,988)
Is the intrapartum ZigZag pattern of fetal heart rate associated with fetal hypoxia and neonatal complications in deliveries?
The intrapartum ZigZag fetal heart rate pattern is an early sign of fetal hypoxia and is significantly associated with cord blood acidemia and severe neonatal complications.
Odds Ratio: 3.3 (95% CI 2.3–4.7)
INTRODUCTION: The aim of the present study was to identify possible associations of fetal heart rate (FHR) patterns during the last 2 hours of labor with fetal asphyxia expressed by umbilical artery acidemia at birth and with neonatal complications in a large obstetric cohort. MATERIAL AND METHODS: , low Apgar scores at 5 minutes, need for intubation and resuscitation, early neonatal hypoglycemia, and neonatal encephalopathy were used as outcome variables. According to the severity of the neonatal complications at birth, the cohort was divided into three groups: no complications (Group 1), moderate complications (Group 2) and severe complications (Group 3). RESULTS: Of the 4988 deliveries, the ZigZag pattern (FHR baseline amplitude changes of >25 bpm with a duration of 2-30 minutes) occurred in 11.7%, late decelerations in 41.0%, bradycardia episodes in 52.9%, reduced variability in 36.7%, tachycardia episodes in 13.9% and uterine tachysystole in 4.6%. No case of saltatory pattern (baseline amplitude changes of >25 bpm with a duration of >30 minutes) was observed. The presence of the ZigZag pattern or late decelerations, or both, was associated with cord blood acidemia (odds ratio OR 3.3, 95% confidence interval CI 2.3-4.7) and severe neonatal complications (Group 3) (OR 3.3, 95% CI 2.4-4.9). In contrast, no significant associations existed between the other FHR patterns and severe neonatal complications. ZigZag pattern preceded late decelerations in 88.7% of the cases. A normal FHR preceded the ZigZag pattern in 90.4% of the cases, whereas after ZigZag episodes, a normal FHR pattern was observed in only 0.9%. CONCLUSIONS: ZigZag pattern and late decelerations during the last 2 hours of labor are significantly associated with cord blood acidemia at birth and neonatal complications. The ZigZag pattern precedes late decelerations, and the fact that normal FHR pattern precedes the ZigZag pattern in the majority of the cases suggests that the ZigZag pattern is an early sign of fetal hypoxia, which emphasizes its clinical importance.
Tarvonen et al. (2020) conducted a cohort in Fetal hypoxia (n=4,988). ZigZag pattern or late decelerations vs. Absence of ZigZag pattern or late decelerations was evaluated on Cord blood acidemia (OR 3.3, 95% CI 2.3-4.7). The presence of a ZigZag fetal heart rate pattern or late decelerations during the last 2 hours of labor was associated with cord blood acidemia (OR 3.3; 95% CI 2.3-4.7).