On the relationship between fetal growth parameters and heart rate variability

Abstract

Background: Fetal growth restriction (FGR) is a challenging pathology causing short and long-term complications. Autonomic malfunction and delayed neurological maturation were found in growth-retarded fetuses. Fetal heart rate variability (HRV) is critically dependent on autonomic regulation. The study was focused on the detection of the relationship between neonatal biometry parameters and HRV variables. Methods: This descriptive cross-sectional study was performed among 40 pregnant women at 22-36 weeks of gestation. FGR was detected in 9 women. The fetal growth was appropriate in 31 patients. The fetal were obtained from an RR-interval time series registered from the maternal abdominal wall via fetal non-invasive electrocardiography (NI-ECG). The stress index (SI) was selected for evaluation among all linear HRV variables. The following conventional cardiotocographic parameters were determined: short-term variation (STV) and long-term variation (LTV). The variables of AC (acceleration capacity) and DC (deceleration capacity) were also detected. Results: The study's findings showed that the detected variables in the FGR were different. However, the small number of cases did not allow statistical significance to proceed. A strong linear correlation was detected between all checked variables of HRV: AC, DC, SI, STV, and LTV. AC and DC demonstrated a significant correlation between them and Apgar score. The results of the multivariate regression model with SI showed a statistically significant relationship with a term of birth and a tendency to have a statistically significant relationship with body weight and head circumference. This suggests that this temporal HRV index may be associated with the anthropometric parameters of newborns. The receiver operating characteristic analysis could be the next stage for the investigation of efficient diagnostic algorithms based on fetal NI-ECG. Conclusions: SI could have utility as a screening program based on fetal NI-ECG in case of a lack of access to high-quality ultrasound or be a valuable addition to existing perinatal strategies.