The effect of electrical stimulation on behavioral states in the fetal lamb

Brachial nerve stimulation at two frequencies (0.01 and 0.05 pulse per second, pps) with the fetus in either low-voltage electrocortical activity with eye movements or high-voltage electrocortical activity without eye movements was studied in five chronically catheterized fetal lambs at 130 to 140 days' gestation. During low-voltage electrocortical activity with eye movements, there were slight alterations in electrocortical state and electromyographic activity at 0.01 pps. At 0.05 pps these electromyographic changes were enhanced above those expected as a result of state changes but returned to control values during the recovery period. During high-voltage electrocortical activity without eye movements, the state changes were much more dramatic, while electromyographic activity increased significantly only at 0.05 pps. It was of note that in both high- and low-voltage electrocortical activity the fetal heart rate changed only during the recovery period at 0.05 pps. It is concluded that fetal behavioral state influences the interpretation of biophysical measurements in the fetus and that the effect of stimulation is more pronounced if applied when the fetus is in high-voltage electrocortical activity without eye movements.     

The effect of fetal behavioral states on middle cerebral artery peak systolic velocity

OBJECTIVE: This study was undertaken to determine whether is there a difference in the middle cerebral artery peak systolic velocity (MCA PSV) between active and resting behavioral states in healthy fetuses aged 30 to 32 weeks. METHODS: MCA blood flow was measured by pulsed Doppler sonography 3 times during each fetal behavioral state (active and resting). The average during active state was compared during the resting state. Statistical analysis was performed by paired t test. RESULTS: During the fetal active state, there was a significant increase in the mean PSV (51.59 cm/s vs 46.95 cm/s, P < .0001) and mean end-diastolic velocity (9.59 cm/s vs 7.98 cm/s, P=.0015), and a significant decrease in the mean pulsatility index (PI) (2.07 vs 2.19, P=.0226) and the mean resistance index (0.83 vs 0.85, P=.0481). CONCLUSION: Healthy preterm fetuses have a significantly higher MCA PSV during the active state. Activity state should be considered when interpreting MCA Doppler indices.     

The relationship between fetal activity and behavioral states and fetal breathing movements in normal and growth-retarded fetuses

The incidence of fetal breathing was studied during the course of behavioral state observations on 28 low-risk fetuses between 32 and 40 weeks' gestational age and on 12 growth-retarded fetuses between 36 and 40 weeks. Real-time ultrasound scanners were used to detect fetal eye, body, and breathing movements, and the fetal heart rate was recorded continuously. The mean duration of the observation sessions was 110 minutes. The mean incidence of fetal breathing was greater during periods of fetal activity (body and eye movements present, greater heart rate variability) than during quiescence (body and eye movements absent, narrowed heart rate variability) at all gestational ages studied in both low-risk and growth-retarded fetuses. During periods when one of the state variables (body movements, eye movements, heart rate pattern) was in its active condition while the other two were quiet, or the reverse, the incidence of fetal breathing was intermediate between those found when all three state variables were in agreement. After behavioral states had developed, at 38 and 40 weeks, the mean incidence of fetal breathing in the low-risk fetuses was greater during active states than during the quiet state. There was no apparent increase in the degree of linkage between fetal breathing and other expressions of fetal activity after the emergence of behavioral states.     

Four-dimensional sonography in the assessment of fetal functional neurodevelopment and behavioral patterns

During the past few decades, morphological studies of fetal brains as well as ultrasonic imaging of fetal intrauterine activities in real time have provided invaluable information about the most important events in the development of human central nervous system. It has been shown that development of fetal brain proceeds through a sequence of complicated histogenetic processes, which are reflected in the fetal behavioral patterns. Major developmental events, such as the establishment of neural connections in different regions of the brain, are accompanied by the occurrence of new patterns of fetal activities or by the transformation of existing patterns. It has been suggested that the ultrasound assessment of fetal behavior could be used for the evaluation of the integrity of fetal central nervous system and, possibly, for the detection of functional or structural brain disorders. The new, advanced imaging techniques such as four-dimensional sonography might open a new perspective for the study of fetal behavioral patterns and facilitate the development of diagnostic strategies for early detection or prevention of brain dysfunctions. The importance of these investigations is underlined by the recent findings that many environmental influences causing the fetal stress can interfere with the fetal neurodevelopment and leave long-term and profound consequences on brain structure and function. The major events in the functional development of fetal brain, as well as the influence of environmental factors on fetal neurodevelopment, are discussed in this review.     

Human fetal ductal flow velocity waveforms relative to behavioral states in normal term pregnancy

In 16 normal pregnancies the relationship between the blood flow velocity waveform and fetal behavioral states at 37 to 38 weeks' gestation was studied. Whereas behavioral state independency was established for the acceleration time, peak flow velocity demonstrated a statistically significant reduction during active sleep, compared with quiet sleep. These data reflect reduced ductal flow and suggest a redistribution in the left-ventricular and right-ventricular output in favor of the left side of the heart during active sleep. Peak flow velocities in the fetal ductus arteriosus were independent of fetal heart rate.     

Automated analysis of near-term antepartum fetal heart rate in relation to fetal behavioral states: the Sonicaid System 8000.

Fetal heart rate and fetal movements were recorded in 16 uncomplicated near-term pregnancies. The recordings were used to evaluate a system for automated fetal heart rate analysis (Sonicaid System 8000). Fetal rest-activity patterns were considered in the analysis. The mean duration of C2F periods "active sleep," 33 minutes) was significantly greater than that of C1F periods ("quiet sleep," 19 minutes) (p less than 0.001). The incidence of accelerations and decelerations and the overall fetal heart rate variations were greater during C2F than during C1F (p less than 0.001). In 11 of 16 C1F periods, the system classified the fetal heart rate variation as "questionable" or "abnormal." Episodes of high variation were identified in only 3 of 16 C1F periods, but they were found in all 18 C2F periods. Episodes of low variation were identified in 14 of the 16 C1F periods but were not found in any C2F periods. During C2F periods, the system's criteria of normality were met in all cases but one; they were not met during any of the C1F periods. Thus the diagnosis of fetal distress should not be based merely on the absence of accelerations, low fetal heart rate variation, or absence of episodes of high variation in recordings with a duration of less than 45 minutes.     

Computerized fetal heart rate analysis in labor

Observer variation in visual analysis of fetal heart rate (FHR) records is reportedly high, but can be avoided by computerized numerical analysis. The FHRs of 394 women in labor at 37 or more weeks' gestation were recorded on-line and analyzed to examine how different patterns related to outcome, as judged by umbilical arterial base deficit or Apgar score on delivery. The range of normality and the diversity of patterns of those delivered without acidemia were great. Late decelerations were of poor prognostic value. There was an increase in FHR variation during labor averaging 40%. In this preliminary study, conventional attributes of the FHR, alone or in combination, did not predict metabolic acidemia. Epidural analgesia in 240 women was identified as a confounding variable that significantly affected FHR patterns without influencing the condition of the infant at birth. It was associated with a higher FHR, less FHR variation and fewer decelerations, primiparity, longer labors, more operative deliveries, and a threefold greater cesarean rate. The rise in basal FHR, perhaps due to a rise in maternal temperature, may partly explain the high intervention rate in those without fetal acidemia.     

Influence of the fetal scalp electrode stimulation test on fetal heart rate and body movements in quiet and active behavioral states during labor

Thirty women were studied to examine the effect of fetal scalp stimulation on fetal heart rate (FHR) accelerations and gross body movements in quiet and active fetal behavioral states during the active phase of labor. Stimulation was performed by five consecutive tractions of the fetal scalp electrode. Fetal response in terms of fetal movements and FHR accelerations occurring within 15 seconds after stimulation was observed in all fetuses of the active state group. In the quiet state group 14 of 15 fetuses responded with body movements and in 12 fetuses FHR accelerations were observed. Subsequently, most of the fetuses returned to the quiet state. We suggest that a normal and healthy fetus is expected to respond to the fetal scalp electrode stimulation test even in the quiet behavioral state.     

Computerized assessment of facial hair growth.

OBJECTIVE: To evaluate a computer-assisted technique for objective and sensitive monitoring of facial hair growth. DESIGN: Prospective study. SETTING: Department of Gynecological Endocrinology and Reproductive Medicine and Clinic for Ear, Nose, and Throat, General Hospital, University of Vienna, Vienna, Austria. PATIENT(S): Four men, three hirsute women, and three nonhirsute women. INTERVENTION(S): Using video equipment and computer software, we were able to document, analyze, and store data regarding hair growth in specific areas of interest. For digital image analysis, we used the Digi Trace System (Olympus, Vienna, Austria; Imatec, Munich, Germany). MAIN OUTCOME MEASURE(S): Hair growth within 20 days in well-defined regions of interest on the faces of hirsute and nonhirsute women and of men. RESULT(S): Hair growth on day 21 was significantly different between hirsute and nonhirsute women as well as in men. The scores for individual hair growth between day 0 and day 21 also were significantly different in hirsute women and in men. No statistically significant difference in hair growth was found within the group of nonhirsute women. CONCLUSION(S): With digital image analysis, facial hair growth, especially in hirsute women, can be calculated in a sensitive and objective manner.     

Human fetal behavioral state at term

The present study was designed to test the existence of behavioral states in the fetus at term using simplified techniques. For this purpose simultaneous recording of the fetal heart activity by means of phonocardiotocography and of fetal body movements by means of real-time ultrasound was performed by using a multichannel recorded. The fetal heart activity was analyzed for two parameters: (1) long-term variability and (2) baseline accelerations. The fetal body movements were classified into three types. 880 min of recording time from 50 fetuses at 37-41 weeks of gestation were analyzed. Each segment of 1 and 3 min was classified into four distinct states, according to the combination of the above parameters. The segments that failed to fit into one of these states were labeled as 'no state'. The frequency of each parameter was also independently calculated. The results were statistically analyzed by using a computer. The significance of the difference between the observed frequencies of the various states and their expected frequencies (obtained by the frequencies of the individual parameters) was calculated by the chi 2 test. Behavioral states of a duration of 3 min were observed in 45.6% of the total periods recorded which is significantly higher (p less than 0.001) than the 4.1% expected.     

Antenatal assessment of fetal well-being

Assessment of fetal well-being is one of the key aims of obstetric care. This article reviews various tools and interventions that are currently available to assess fetal well-being, including the ongoing assessment of risk factors (leading to the triaging of women into appropriate pathways of care) through to the assessment of fetal well-being with the computerised CTG. Included is a brief overview of screening, symphysis fundal height measurements, growth and Doppler scanning, and perception of fetal movements. A good history, clinical assessment, and appropriate use and interpretation of investigations form a holistic approach for assessment of fetal well-being.     

Computerized analysis of fetal heart rate parameters by gestational age.

OBJECTIVE: The aim of this study is to define the reference ranges for fetal heart rate (FHR) parameters according to gestational age, by determining the relationship between the FHR and gestational age using a computerized FHR analysis system. METHODS: Using our own software developed by Hanyang University Hospital in Korea, non-stress tests were performed for 20 min. FHR parameters for 6455 subjects were analyzed for various gestational groups; <25 weeks, 25-28 weeks, 29-32 weeks, 33-36 weeks, 37-40 weeks, and >40 weeks. RESULTS: The FHR parameters were related to gestational age. The mean baseline FHR, signal loss, and fetal movements decreased significantly with gestation (P<0.0001). The variability and accelerations of FHR were highest for the 37-40 weeks gestational group (P<0.05). CONCLUSIONS: The results showed that overall, the differences in the FHR parameters between gestational groups were statistically significant, and the gestational age of the fetus should be considered when interpreting FHR patterns.