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Published on: November 20, 2015
Fetal heart rate patterns complicated by chorioamnionitis and subsequent cerebral palsy in Japan
Tomoko Yamaguchi-Goto1, Masanao Ohashi1,2, Yuki Kodama1,3
1Department of Obstetrics and Gynecology, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan.
Insights
Chorioamnionitis can lead to cerebral palsy (CP) in newborns. Terminal bradycardia in fetal heart rate patterns is a key indicator of hypoxic-ischemic encephalopathy in infants with CP.
Area of Science:
- Obstetrics and Gynecology
- Neonatology
- Neurology
Background:
- Chorioamnionitis is a significant risk factor for adverse neonatal outcomes, including cerebral palsy (CP).
- Understanding the relationship between fetal heart rate (FHR) patterns and CP in infants exposed to chorioamnionitis is crucial for timely intervention.
Purpose of the Study:
- To investigate the association between specific FHR patterns and the development of CP in infants born at or near term with chorioamnionitis.
- To identify predictive FHR markers for hypoxic-ischemic encephalopathy (HIE) in this high-risk population.
Main Methods:
- Retrospective analysis of a nationwide population-based database of CP cases in Japan.
- Inclusion of 133 infants with chorioamnionitis born at ≥34 weeks gestation.
- Fetal heart rate chart interpretation using National Institute of Child Health and Human Development criteria and MRI for all enrolled infants.
Main Results:
- The incidence of CP in infants with chorioamnionitis (≥34 weeks gestation) was 0.3 per 10,000 live births in Japan.
- 88% of infants with CP showed hypoxic-ischemic encephalopathy (HIE) on MRI.
- Terminal bradycardia was observed in 50% of CP infants, exclusively leading to HIE; other infants without bradycardia but with acidosis also developed HIE.
Conclusions:
- Terminal bradycardia in fetuses with chorioamnionitis is a strong predictor of HIE and subsequent CP.
- FHR patterns such as late decelerations and decreased variability were frequent before terminal bradycardia.
- Early recognition of concerning FHR patterns in chorioamnionitis cases is vital for managing neonatal brain injury risk.
Aim:
This retrospective study was performed to investigate whether certain fetal heart rate patterns were associated with subsequent cerebral palsy (CP) in infants with chorioamnionitis at or near term.
Methods:
We used cases registered by the Japan Obstetric Compensation System for CP, which is a nationwide population-based database. Among them, 133 infants with chorioamnionitis who were born at ≥34 weeks of gestation were enrolled. All infants underwent magnetic resonance imaging (MRI), and all fetal heart rate charts had been interpreted according to the National Institute of Child Health and Human Development criteria, focusing on antepartum and immediately before delivery.
Results:
The incidence of CP after chorioamnionitis at ≥34 weeks of gestation was 0.3 per 10 000 in Japan. Between the clinical (24%) and subclinical groups (76%), the incidence of abnormal fetal heart rate patterns did not differ. According to the MRI classification, 88% of the infants with CP showed hypoxic-ischemic encephalopathy. Half of the infants with CP experienced terminal bradycardia, leading to severe acidosis and exclusively to hypoxic-ischemic encephalopathy. In another half, who did not experience bradycardia, 80% had moderate acidosis (pH 7.00-7.20) resulting in hypoxic-ischemic encephalopathy, and the remaining 20% showed non-acidosis resulting in brain damage other than hypoxic-ischemic encephalopathy. The fetal heart rate patterns before the terminal bradycardia showed that the incidence rates of late deceleration or decreased variability were high (>60%).
Conclusion:
Fifty percent of pregnant women with chorioamnionitis-related CP had terminal bradycardia that exclusively resulted in hypoxic-ischemic encephalopathy.
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