An exploratory study on maternal-fetal heart rate variability during normal and operative vaginal delivery: physiopathological, behavioral and clinical perspectives

Objective. Operative vaginal delivery (OVD) is a major obstetrical issue in developed countries. In this study, we analyzed simultaneous maternal (MHR) and fetal heart rate (FHR) variabilities, as markers of maternal and fetal autonomous nervous systems activity, in relation with OVD. Approach. A set of 44 simultaneous MHR and FHR recordings were obtained from distinct singleton term pregnancies in normal (n = 27) and OVD (n = 17) in the last two hours of labor (H1 and H2), and were analyzed using linear and nonlinear indices of heart rate variability analysis. Interaction between MHR and FHR was assessed through their differences and cross-sample entropy analysis. Main results. With progression of labor, there was an increase in most MHR and FHR linear indices, a decrease of entropy indices and an increase of MHR and FHR synchrony/regularity, whereas the sympatho-vagal balance (LF/HF) increased in the mother but decreased in the fetus. Mean MHR, predominance of low frequencies (LFnorm) and LF/HF were significantly higher in the OVD group, while the opposite occurred with the high frequencies (HF) and entropy. The synchronization/regularity between MHR and FHR was significantly higher in OVD. A sensitivity and specificity of 94.1% and 70.4%, respectively, were achieved in the classification of OVD cases using an univariate linear discriminant. Significance. Maternal-FHR variability analysis adds information regarding intrapartum physiology and maternal-fetal behavior and might be considered in prediction models.