임신주수에 따른 임신중 무뇌아 심장박동 각 변수의 분석

Abstract

Objectives: The purpose of this study was to evaluate various FHR parameters of anencephalic fetuses and to assess the effect of the fetal nervous system on FHR according to gestational age, and to quantify changes in fetal heart rate (FHR) parameters after vibroacoustic stimulation (VAS) and to evaluate the usefulness of VAS testing (VAST) in anencephalic fetuses. Our findings may also help to clarify the route(s) of vibration and sound transmission during VAST.

Study Design: The antepartum non-stress test (NST) was performed in 25 anencephalic fetuses. Each FHR parameter was analyzed using a computerized FHRanalysis system for various gestational groups, and the results were compared with results from a normal control group (N=25). After excluding nine of the remaining 25 fetuses which did not perform both NST and VAST simultaneously, we obtained the antepartum FHR tracings of 16 anencephalic fetuses, including both the NST and VAST. We determined all FHR parameters from data collected for 10-min before and 10-min after VAS, at successive gestational stages. Thus, from 16 anencephalic fetuses, we analyzed the FHR data from antepartum FHR tracings taken 10 min before and 10 min after VAS.

Results: The mean baseline FHR of anencephalic fetuses decreased with increasing gestational age, as in normal fetuses. FHR variability increased with increasing gestational age, as in normal fetuses. Further, we observed three false reactive responses at term. The false reactive rate for VAST (3/16) was higher than that for NST (1/16). No FHR parameters increased significantly after VAS except for the number of fetal movements (FM), which increased significantly in all gestational groups (25th-32nd and 33rd-40th weeks).

Conclusions: In anencephalic fetuses, baseline FHR and FHR variability changed significantly with gestational age. These results suggest that the autonomic nervous system is more likely to be preserved than the central nervous system (CNS) in anencephalic fetuses in spite of malformed or insufficient CNS. Further, these findings call attention to an increased probability of a false reactive response in VAST analysis, when the fetus is affected by a CNS disorder. Increased numbers of FM after VAS suggest that the vibratory pathway is more likely to elicit fetal response than the auditory pathway in this setting, and that the vibratory stimulation travels by subcortical rather than by cortical pathways.