Objective: Previous studies demonstrated that fetuses of black women were more likely to show non-reactive non-stress test (NST), either in baseline conditions or during vibratory-acoustic stimulation. The aim of the present study is to apply a computerized Non Stress Test (NST) to compare fetuses of black and Caucasian women.
Patients and Methods: 114 pregnant women at term who referred to the Safe Motherhood Clinic for the antenatal routine evaluation were considered eligible for a prospective, case-control study. For every black woman, Italian born and Maghreb coming women at similar gestational week (+/- 1 week), were enrolled. Each woman was submitted to computerized NST for 60 minutes. A multiparametric analysis including spectral parameters from autoregressive models and nonlinear algorithms (approximate entropy) was also applied.
Results: The fetal heart rate of fetuses of black women significantly differed in comparison to the others: they showed lower episodes of large accelerations and higher values of approximate entropy. However, the acid-base status did not differ between groups, thus excluding that fetuses of black women were more likely to experience intra-partum distress.
Conclusions: Antenatal fetal heart rate differences among different population should be considered in the non-stress test evaluation. In particular as far as the black women are concerned, further developments in ante-partum fetal algorithms are needed in order to avoid a wrong interpretation of NST features.