Symposium
Chair: Janet A. DiúPietro
Discussant: William P. Fifer
'How early in the fetal period are differences between individuals detectable, and to whatextent are such differences prognostic of differences in childhood, or even at maturity?' (Sontag& Richards, 1938, pg 65) The focus of this symposium echoes the question posed by the pioneering research ofSontag and colleagues at the Fels Institute early in this century. Since that time, technologicadvances in methods of fetal surveillance have opened a window to the fetus enablinginvestigation of issues which lie at the heart of developmental inquiry. In the 1960's, interest inestablishing individual differences earlier in childhood, including the infant and neonatal periods,served, in part, as impetus to the establishment of ISIS and other similar professionalorganizations. At the turn of this century, new methods and applications have resulted in a rapidlygrowing body of literature on the origins of behavior and ascertainment of individual differencesbefore birth. Investigation of the fetal period also allows study of potential maternal factors whichmay directly influence individual differences and later development. The conceptual rubricsurrounding fetal research typically represents a downward extension of that developed for infantsand young children. Temperament by definition is constitutional, and birth itself is not a period ofsignificant discontinuity in behavior. In each presentation, patterns of reactivity and regulationform the core constructs in both fetal and postnatal characteristics selected for study. The goal ofthis symposium is to present research programs that are at the leading edge of this movement;research programs from three countries are represented. Methods to quantify neurobehaviorbefore birth are relatively new and not widely disseminated, so each presentation will highlight theprocedures developed to collect fetal data. The first presentation will detail patterns of fetal habituation using an externalvibroacoustic device. Prior work of these investigators has focused on deleterious influences ofthe maternal-placental neuroendocrine axis on length of gestation and birth weight; this studyincludes investigation of fetal functioning as an index of neural integrity in order to betterunderstand the role of maternal factors on fetal development and outcome. The next threepresentations evaluate the predictive validity of fetal neurobehaviors in the development andtemperament of the neonate, infant, and child. The second presentation in the symposium focuseson a specific infant behavior: persistent crying, often referred to as 'colic'. The origins ofpersistent crying remain unknown, leading the investigators to explore whether there are fetalmanifestations of atypical reactivity. The third presentation will present data from twolongitudinal studies which endeavour to predict early infant neurobehavioral outcomes fromcongruent fetal neurobehavioral measures, assessed at multiple times during pregnancy. The finalpresentation will describe results of a longitudinal study commencing with the fetus and extendingthrough ages 8 and 9. This, perhaps the longest prospective study of fetal neurobehavior, linksfetal behavioral state and motor behavior as precursors with personality dimensions that are mostapparent in later childhood. The symposium will conclude with remarks by a discussant who hasplayed an integral role in illuminating the role of the prenatal period in postnatal life.
Details of individual items:
paper
There is a growing recognition that prenatal experience plays a critical role in interactingwith the genome to shape all aspects of brain development, and that these epigenetic influences inintrauterine life may confer a set of predispositions that act throughout the life-span to definevulnerability for a host of chronic degenerative diseases (i.e., the concept of fetal programming ofadult disease). In this context, environment, or experience, is a double-edged sword, whereinoptimal environments may produce beneficial effects and hostile environments may producedeleterious effects on the brain. Previous studies by our group have reported the maternalenvironment during pregnancy exerts a significant influence on infant birth outcomes (length ofgestation, birthweight), mediated, in part, by the maternal-placental neuroendocrine axis. The direct influence of maternal factors on the developing human fetus is, however, poorlyunderstood. We performed fetal assessments in a sample of 156 mother-fetus pairs at 31-33weeks gestation, including fetal biometry and biophysical profile (BPP); umbilical flowvelocimetry; and an experimental paradigm to quantify fetal heart rate (FHR) reactivity to a seriesof ex-utero vibroacoustic stimuli. Maternal assessments included structured assessments ofpsychosocial and behavioral constructs, maternal plasma bioassays of stress hormones (CRH,ACTH, BE, cortisol), and medical records to abstract and quantify obstetric risk. To date, resultsindicate the following: (a) Fetuses exhibited a significant, non-linear FHR increase in response tothe vibroacoustic stimulation protocol; (b) Baseline FHR, presence of uterine contractions duringtrials, and characteristics of the challenge protocol such as inter-trial interval significantlyinfluenced the magnitude of FHR responses; (c) After accounting for the effects of baseline FHR,uterine contractions and characteristics of the challenge protocol, maternal conditions related topsychological and physiological stress (i.e., psychosocial stress levels, placental CRHconcentrations, umbilical blood flow, and presence of maternal medical risk conditions) weresignificantly associated with the pattern of FHR responses; (d) After an initial response period,fetuses exhibited a FHR response decrement to subsequent stimuli, indicating habituation; (e) Atwo-parameter growth curve (power) model to assess habituation rate accounted forapproximately 70% of the variance in FHR response; and (f) fetal sex and conditions related tomaternal stress (i.e., maternal ACTH concentrations, presence of medical risk conditions) weresignificantly associated with the rate of habituation. Thus, these findings supports a role for theprenatal environment in modulating aspects of human fetal brain development that underlieprocesses related to recognition, appraisal, response, memory and habituation.
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Persistent, unexplained crying in 1-3 month old infants is a common cause of distress forparents, is costly for health services, and may trigger maternal depression or even infant abuse inrare cases. There are no agreed policies for managing the crying, but lay and medical literaturesagree on the need for progress. Recent studies have changed how this crying is viewed. Forexample, although the crying is relatively intense, no evidence has been found that it has an abruptonset or sounds abnormal, as implied by the belief that it is due to gastrointestinal pain (colic).Although poor parenting may sometimes contribute to infant crying, most cases have been foundto occur in spite of excellent parental care. Further, the crying has been found to be objectivelyhard to soothe, for trained researchers as well as parents. Instead of being self-limiting' - in thesense that the crying lasts only until 3 months of age - individual differences in crying and fussinghave been found to be stable over the first 6-9 months of age. These and other findings suggest that differences in how much infants cry may reflecttemperament-like individual differences in reactivity or regulation of response to environmentalstimuli. In temperament theory, highly reactive individuals have a low threshold, respondintensely, and have a long response duration. On this basis, individuals who cry a lot should havelong, relatively intense, hard-to-soothe crying bouts in everyday circumstances. Our own andothers' findings are consistent with these expectations. If persistent crying in early infancy is due to temperamental reactivity, such individualsmight be detected before they are born. In keeping with this hypothesis, we have recentlycompleted a provisional study using fetal movement charts to predict the same individuals'postnatal crying. The frequency of small movements distinguished reliably between fetuses andpredicted the amounts the same individuals cried at 1, 6 and 12 weeks of age. This presentationwill summarise these findings and discuss the underlying rationales. We will also present the firstdata from a current study designed to confirm the findings and provide evidence which bearsdirectly upon the reactivity hypothesis. Using maternal logs and fetal ultrasound recordings, 40fetuses with high movement levels, and 40 with low movement levels, are being selectedat 37 weeks of pregnancy. After birth, the babies' reactivity to the Guthrie PKU test and during astandard newborn examination (the NAPI test) are being measured objectively, while theirspontaneous crying is being monitored using 24 hour audiorecordings and behaviourdiaries. Data collection will be completed and we will be able to provide answers to 2 centralquestions by July 2000: (1) Do newborns who cry a lot in everyday circumstances cry moreintensely and for longer periods in response to the standard challenges of the Guthrie test andNAPI examination?; (2) Do the objective measures confirm that an infant's crying can bepredicted by fetal movement records obtained before birth?
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Birth is not a particularly remarkable event for behavior. Virtually all the behaviorspresent in the neonate have been identified in the fetus. Individual differences in neurobehavioralexpression among fetuses parallel the degree of those observed in early infancy. There is apaucity of data pertaining to the degree to which individual differences in fetal neurobehavioralfunctioning are preserved after birth and whether these characteristics are precursors totemperamental attributes or other developmental indices. Although the manner in whichtemperament is classified varies across development, the core processes of individual differencesare considered to involve elements of reactivity and regulation, which, in turn, are expected torepresent an underlying neural substrate. In prior work, we have demonstrated that stableindividual differences in heart rate and variability, motor activity, and state regulation existbeginning midway through gestation. In addition, we have shown that antenatal characteristicsaccount for between 22% and 60% of the variance in maternally reported temperament at 3 and 6months postpartum. However, reliance on maternal report of temperament introduces a numberof limitations. The current study was designed to incorporate objective, laboratory-basedmeasures of infant neurobehavioral functioning to assess the predictive validity of fetalneurobehavioral assessments. Fetal data were collected on fifty-two normal fetuses at 24, 30, and 36 weeks gestation. At each visit, fifty minutes of Doppler-based fetal movement and heart rate data were digitizedon a computerized system designed by us and quantified in terms of a variety of measuresincluding heart rate, variability, activity level, and behavioral state. Data on maternalpsychological stress and personality factors were also collected at each visit. A subset of thesefetuses were assessed at 2 weeks (n 41), using a standard neurobehavioral exam and at 1-year(n 35), using episodes selected from the Laboratory Temperament Assessment Battery(Goldsmith & Rothbart). Infant heart rate and vagal tone measures were also collected. Resultsfrom the 2 week follow-up indicate that a) fetal heart rate is significantly associated with earlyinfant heart rate and variability; b) fetal state maturity is associated with better orientation scoresand state regulation; and c) low fetal motor activity is associated with examiner-rated fragility andpoor testability. Data analyses for the 1 year follow-up are incomplete at the time of conferencesubmission, but will be finalized by that time. Ultimate models for both 6 week and 1 yearpredictions will be based on regression models which include both fetal neurobehavioral measuresand maternal prenatal stress and affective factors. Findings from this study will contribute to thefew sources of data which are able to evaluate consistencies from prenatal to postnatal life usingobjective ascertainment and reliably quantified measures of fetal neurobehavioral functioning.
paper
Temperament can be seen as an important construct to explain individual variation in behaviorand mood. Three important issues dominate the empirical and theoretical work in this field: thebiological basis of temperament and behavior, the degree of preservation of the differenttemperamental dispositions, and developing a consensus on the theoretically most usefultemperamental constructs. With our study we hope to add to the discussion on this issues andextend this discussion to the prenatal period. In a prospective longitudinal design we have studied the effects of maternal anxiety and stressduring pregnancy in 71 mother-child pairs. In the first wave, data were gathered and analyzed ateach trimester of pregnancy and in the 1st, 10th and 28th week after birth. Maternal measuresincluded stress-evoking, stress-mediating and resulting factors as well as anxiety (STAI,Spielberger et al.). Child measures included behavioral states assessed during both the fetal andneonatal periods, and aspects of infant temperament and behavior. Maternal-infant interaction wasalso studied. Univariate and multivariate analysis of these data revealed that maternal prenatalanxiety had an effect on fetal and neonatal motor behaviour and behavioural states, as well asaspects of infant behavior (crying, temperament) but not on neonatal neurological state, infantfeeding behaviour or motor and mental development. The second wave of the project assessed the children at eight and nine years old. Again datawere gathered on maternal stress and anxiety, and on the child's temperament (IBQ, Rothbart etal.), self-concept (SPPC, Harter) and behavioral problems (CBCL, Achenbach; TRS, Conners).The data gathered at each measurement point were reduced with factor and component analysis.Multi- and univariate analysis were performed to study the relationship between the factors andcomponents at the different measurement points. In this analysis we concentrate on analysis of the Children's Behavior Questionnaire (CBQ,Rothbart et al.) Rothbart et al. describe temperament systems with reference to the affective,arousal and self-regulatory components thought to underlie them. The second order factoranalysis performed on 15 subscales of the CBQ revealed three factors that were similar to thedimensions reported in American and Japanese populations: (1) positive affect and approach(underlying what is variously labeled Extraversion or Positive Emotionality), (2) negative affectand related behaviors (underlying what is variously labeled Neuroticism, Anxiety or NegativeEmotionality) and (3) the attentional self-regulatory systems (underlying what may be describedas Constraint or Effortful Control). Prenatal and neonatal precursors of these dimensions andrelations with other concurrent behavioural measures (e.g. TRS Conners, CBCL Achenbach) areanalyzed and discussed.