Computerized analysis of behavior in fetuses with congenital abnormalities

STUDIES IN FETAL BEHAVIOR: REVISITED, RENEWED, AND REIMAGINED

Among the earliest volumes of this monograph series was a report by Lester Sontag and colleagues, of the esteemed Fels Institute, on the heart rate of the human fetus as an expression of the developing nervous system. Here, some 75 years later, we commemorate this work and provide historical and contemporary context on knowledge regarding fetal development, as well as results from our own research. These are based on synchronized monitoring of maternal and fetal parameters assessed between 24 and 36 weeks gestation on 740 maternal-fetal pairs compiled from eight separate longitudinal studies, which commenced in the early 1990s. Data include maternal heart rate, respiratory sinus arrhythmia, and electrodrmal activity and fetal heartrate, motor activity, and their integration. Hierarchical linear modeling of developmental trajectories reveals that the fetus develops in predictable ways consistent with advancing parasympathetic regulation. Findings also include:within-fetus stability (i.e., preservation of rank ordering over time) for heart rate, motor, and coupling measures; a transitional period of decelerating development near 30 weeks gestation; sex differences in fetal heart rate measures but not in most fetal motor activity measures; modest correspondence in fetal neurodevelopment among siblings as compared to unrelated fetuses; and deviations from normative fetal development in fetuses affected by intrauterine growth restriction and other conditions. Maternal parameters also change during this period of gestation and there is evidence that fetal sex and individual variation in fetal neurobehavior influence maternal physio-logical processes and the local intrauterine context. Results are discussed within the framework of neuromaturation, the emergence of individual differences, and the bidirectional nature of the maternal-fetal relationship.We pose a number of open questions for future research. Although the human fetus remains just out of reach, new technologies portend an era of accelerated discovery of the earliest period of development

Placental pathology in pregnancies with maternally perceived decreased fetal movement--a population-based nested case-cohort study

Background

Decreased fetal movements (DFM) are associated with fetal growth restriction and stillbirth, presumably linked through an underlying placental dysfunction. Yet, the role of placental pathology has received limited attention in DFM studies. Our main objective was to explore whether maternal perceptions of DFM were associated with placental pathology in pregnancies recruited from a low-risk total population.

Methods/Principal Findings

Placentas from 129 DFM and 191 non-DFM pregnancies were examined according to standardized macro- and microscopic protocols. DFM was defined as any maternal complaint of DFM leading to a hospital examination. Morphological findings were timed and graded according to their estimated onset and clinical importance, and classified in line with a newly constructed Norwegian classification system for reporting placental pathology. With our population-based approach we were unable to link DFM to an overall measure of all forms of placental pathology (OR 1.3, 95% CI 0.8–2.2, p = 0.249). However, placental pathology leading to imminent delivery could be a competing risk for DFM, making separate subgroup analyses more appropriate. Our study suggests a link between DFM and macroscopic placental pathology related to maternal, uteroplacental vessels, i.e. infarctions, placental lesions (intraplacental hematomas) and abruptions. Although not statistically significant separately, a compound measure showed a significant association with DFM (OR 2.4, 95%CI 1.1–5.0, p = 0.023). This association was strengthened when we accounted for relevant temporal aspects. More subtle microscopic materno-placental ischemic changes outside the areas of localized pathology showed no association with DFM (OR 0.5, 95%CI 0.2–1.4, p = 0.203). There was a strong association between placental pathology and neonatal complications (OR 2.9, 95% CI 1.6–5.1, p<0.001).

Conclusions

In our population-based study we were generally unable to link maternally perceived DFM to placental pathology. Some associations were seen for subgroups.

Fetal heart rate tracing patterns associated with congenital hypothyroidism

OBJECTIVE

This study was undertaken to determine fetal heart rate (FHR) tracing patterns associated with congenital hypothyroidism.

STUDY DESIGN

FHR patterns of 59 women whose babies were diagnosed with congenital hypothyroidism were retrospectively compared with tracings of 78 of their siblings. Tracings were interpreted during the first stage of labor. Multivariable analysis was used to control for confounders.

RESULTS

Neonates with congenital hypothyroidism had significantly higher rates of reduced variability in FHR tracing patterns as compared with those without congenital hypothyroidism (49.2% vs 3.8%; odds ratio, 24.1; 95% confidence interval, 6.8-85.3; P < .001). No significant differences were noted between the groups regarding decelerations or baseline abnormalities. The significant association between congenital hypothyroidism and reduced variability persisted after controlling for confounders such as treatment with pethidine, MgSO4, and gestational age (odds ratio, 14.1; 95% confidence interval, 1.1-190.7; P = .046).

CONCLUSION

Congenital hypothyroidism is significantly and independently associated with reduced variability in FHR tracing patterns.

Neurobehavioral assessment before birth

The complexities of neurobehavioral assessment of the fetus, which can be neither directly viewed nor manipulated, cannot be understated. Impetus to develop methods for measuring fetal neurobehavioral development has been provided by the recognition that individual differences in neurobehavioral functioning do not originate with birth and acceptance of the key contribution of the antenatal period to postnatal life. Research has centered around four aspects of fetal functioning: heart rate, motor activity, behavioral state, and responsivity to stimulation. Longitudinal studies have revealed that the developmental trajectories of these characteristics parallel the developing nervous system, detected a transitional period between 28 and 32 weeks gestation, and established within-fetal stability during the second half of gestation. Despite the promise of fetal stimulation and habituation paradigms as measures of neural functioning, significant safety and ethical concerns exist. Construction of a unified fetal neurobehavioral scale is premature until a sufficient degree of normative data is available and the predictive validity of specific aspects of fetal neurobehavior to child developmental outcomes is better established.

Decreased fetal movements: background, assessment, and clinical management

A reduction or cessation of fetal movements (FMs) is frequently reported by pregnant women and causes concern and anxiety. However, the clinical significance of a history of reduced FMs remains unclear, and the assessment and management of these pregnancies is controversial. This article is a review of the literature on decreased FMs found in medline and the cochrane library using the search phrases: decreased FMs, perinatal outcome, FM monitoring, and fetal assessment. Formal counting of FMs by the pregnant woman could possibly identify the fetuses, which are at risk of compromise, thus allowing for appropriate action. However, the benefit of this intervention has not been definitely proven. Cardiotocography, umbilical/uterine artery Doppler velocimetry, and ultrasonography have been used for antepartum fetal assessment in pregnancies with decreased FMs, but the evidence of a clinical benefit is limited. The effects of fetal assessment with vibroacoustic stimulation and biophysical profile are unknown and should be further evaluated. Present recommendations on the management of pregnancies with decreased FMs are based on limited and inconsistent scientific evidence. There is a need for further well-designed studies in order to provide evidence-based guidelines in the future.

Fetal Neurobehavioral Development: A Tale of Two Cities

Longitudinal neurobehavioral development was examined in 237 fetuses of low-risk pregnancies from 2 distinct populations--Baltimore, Maryland, and Lima. Peru--at 20, 24, 28, 32, 36, and 38 weeks gestation. Data were based on digitized Doppler-based fetal heart rate (FHR) and fetal movement (FM). In both groups. FHR declined while variability, episodic accelerations, and FM-FHR coupling increased, with discontinuities evident between 28 and 32 weeks gestation. Fetuses in Lima had higher FHR and lower variability, accelerations, and FM-FHR coupling. Declines in trajectories were typically observed 1 month sooner in Lima, which magnified these disparities. Motor activity differences were less consistent. No sex differences in fetal neurobehaviors were detected. It is concluded that population factors can influence the developmental niche of the fetus.

Fetal learning: a prospective randomized controlled study

OBJECTIVES

To examine whether prenatal exposure to a music stimulus alters fetal behavior and whether this continues into the newborn period.

SUBJECTS AND METHODS

A prospective randomized control trial was conducted using an exposure learning model in 20 normal term pregnancies. Music was played to ten fetuses via a headphone on the maternal abdomen. Ten controls had the headphone without sound. All fetal studies took place within 72 h prior to elective delivery. All 20 newborns were exposed to the same music on days 3-5. Computerized assessment of fetal heart rate and activity was documented and neonatal behavioral states were recorded. Nonparametric statistical analysis was used.

RESULTS

For the first hour of study, exposed fetuses had higher mean heart rates (FHR) and spent more time exhibiting high FHR variation compared to unexposed fetuses, but neither of these differences was statistically significant. However, by the fourth hour the exposed fetuses not only demonstrated these two features but also exhibited more state transitions (P = 0.01) and higher FHR variation (P = 0.04) compared to unexposed fetuses. These effects were carried over into the neonatal period with prenatally exposed newborns manifesting more state transitions (P = 0.01) and spending a higher proportion of time in awake states (P = 0.05) when exposed to the same music stimulus.

CONCLUSION

Prenatal music exposure alters the fetal behavioral state and is carried forward to the newborn period. This suggests that a simple form of fetal programming or learning has occurred.

A comparison of fetal behaviour in term fetuses exposed to anticonvulsant medication with unexposed controls

OBJECTIVE

To compare behaviour in term fetuses exposed to anticonvulsants with unexposed controls.

DESIGN

An observational study.

SETTING

Pregnancy Assessment Centre, University Hospital, Nottingham, UK.

SAMPLE

Seventeen fetuses whose mothers were taking anticonvulsants and 94 fetuses whose mothers were on no medication between 28 and 41 weeks.

METHODS

Behaviour (fetal heart rate and activity) was recorded with the use of Doppler ultrasound. The duration of recording was 60 minutes or more in all but four recordings (minimum 49 minutes).

MAIN OUTCOME MEASURES

Behavioural criteria studied were: 1. the relative percentage time spent in low and high variation fetal heart rate patterns; 2. the duration and recurrence of fetal activity; 3. the number of accelerations in low and high fetal heart rate variation; and 4. the number of fetal behavioural state transitions.

RESULTS

The two groups were comparable in terms of maternal age, parity. birthweight, Apgar scores and absence of neonatal problems. There was less fetal activity in the anticonvulsant group, but this was only statistically significant at 33-36 weeks in fetal heart rate pattern B (equivalent to state 2F).

CONCLUSIONS

This study showed that fetuses exposed to anticonvulsant medication exhibited a trend of being less active. There were no other significant differences in behaviour. The data do not support the hypothesis of substantial differences in behaviour in fetuses exposed to anticonvulsants.

A comparison of fetal behaviour in breech and cephalic presentations at term

OBJECTIVE

To evaluate fetal behaviour in breech and cephalic fetuses at term, using a computerised fetal behaviour program.

DESIGN

An observational study.

SETTING

Pregnancy Assessment Centre, University Hospital, Nottingham.

SAMPLE

Twenty-six breech and 58 cephalic fetuses between 36 and 41 weeks.

METHODS

Behaviour (fetal heart rate and activity) was recorded with the use of Doppler ultrasound. The duration of recording was 60 minutes or more in all but four recordings (minimum 49 minutes).

MAIN OUTCOME MEASURES

Behavioural criteria studied were 1. the relative percentage time spent in low and high variation fetal heart rate patterns; 2. the duration and recurrence of fetal activity; 3. the number of accelerations in low and high fetal heart rate variation; and 4. the number of fetal behavioural state transitions.

RESULTS

Breech fetuses differed from the cephalic group in that they were lighter than the cephalic fetuses (median 3105 g vs 3400 g; P < 0.01) and were born to older mothers (median maternal age 30 years vs 28 years; P < 0.01). No significant differences were found in rates of movement, numbers of accelerations and time exhibiting low and high fetal heart rate variation. However, breech fetuses exhibited significantly more state transitions (median 5.2/h vs 3.69/h; P = 0.01).

CONCLUSIONS

This study shows that breech fetuses are neurologically different from their cephalic counterparts in otherwise healthy pregnancies, and that subtle behavioural differences can be demonstrated in utero using this computerised method.

Comparison of unstimulated and stimulated behaviour in human fetuses with congenital abnormalities

Unstimulated (passive) and stimulated behaviour [fetal heart rate (FHR) and movements (FA)] was studied in 32 normal fetuses and 10 fetuses with congenital abnormalities (CA). FHR and FA were recorded using a single 1.5-MHz ultrasound transducer and analysed by computer. A 5-second vibroacoustic stimulus (VAS) ('electronic artificial larynx') was used for the stimulation studies. Thus, passive and stimulated behaviour could be studied in a group of fetuses with known pathologies. One hour was used as the recording time for the passive studies and 20 min for the stimulation studies (10 min pre- and 10 min post-VAS). All CA fetuses had abnormalities of FHR and/or FA on recording passive behaviour compared to normal fetuses. However, 4 of the 10 fetuses with CA had responses to VAS that were within the normal range for both FHR and FA. We do not feel that computerised assessment of stimulated behaviour in fetuses with CA confers any advantage over analysis of passive behaviour.

Computerised analysis of unstimulated and stimulated behaviour in fetuses with intrauterine growth restriction

Unstimulated (passive) and stimulated behaviour, in the form of fetal heart rate (FHR) and activity (FA)) was studied in 32 normal fetuses and 14 fetuses with intrauterine growth restriction (IUGR). FHR and FA were recorded using a single 1.5 MHz ultrasound transducer and analysed by computer. A 5 s vibroacoustic stimulus (VAS) (electronic artificial larynx) was used for the stimulation studies. The IUGR fetuses had significantly different patterns of both unstimulated and stimulated behaviour compared to normally grown fetuses. When unstimulated they had lower FA rates than the normally grown fetuses but this was only statistically significant at 28-31 weeks. They also spent a significantly lower proportion of time exhibiting high FHR variation at 28-31 weeks. Following VAS the IUGR fetuses had lower FA responses at all gestations and lower FHR responses from 32 weeks, though only the differences in FA response at 28-31 weeks were statistically significant. Of the 14 fetuses with IUGR, all but one exhibited passive behaviour (ERR and/or FA) that was outside the 10-90th range, for normally grown fetuses, whilst 6 of the 14 had responses to VAS that were within the normal range. We do not feel that computerised assessment of stimulated behaviour in preterm IUGR fetuses confers any advantage over passive observations.