Gestational stress influences cognition and behavior

Maternal caregiving ameliorates the consequences of prenatal maternal psychological distress on child development

Children exposed to prenatal maternal psychological distress are at elevated risk for a range of adverse outcomes; however, it remains poorly understood whether postnatal influences can ameliorate impairments related to prenatal distress. The current study evaluated if sensitivematernal care during the first postnatal year could mitigate child cognitive and emotional impairments associated with prenatal psychological distress. Prenatal maternal psychological distress was assessed via self-reports of anxiety, depression, and perceived stress for 136 mothers at five prenatal and four postpartum time points. Quality of maternal care (sensitivity to nondistress, positive regard, and intrusiveness reverse-scored) were assessed during a mother-child play interaction at 6 and 12 months. Child cognitive function and negative emotionality were assessed at 2 years, using The Bayley Scales and the Early Childhood Behavior Questionnaire. Elevated prenatal distress was associated with poorer child cognitive function and elevated negative emotionality. Children exposed to elevated prenatal maternal distress did not, however, display these outcomes if they received high-quality caregiving. Specifically, maternal care moderated the relation between prenatal psychological distress and child cognitive function and negative emotionality. This association remained after consideration of postnatal maternal psychological distress and relevant covariates. Sensitive maternal care was associated with altered offspring developmental trajectories, supporting child resilience following prenatal distress exposure.

Fetal exposure to placental corticotropin-releasing hormone (pCRH) programs developmental trajectories

The maternal endocrine stress system is profoundly altered during the course of human pregnancy. The human placenta expresses the genes for CRH as early as the seventh week of gestation and it is the expotential increase in placental CRH (pCRH) over the course of human gestation that is responsible for the greatest modification in the maternal stress system. The bi-directional placental release of hormones into the maternal and fetal compartments has profound influences for both. The influential Fetal Programming model predicted that early or fetal exposures to maternal signals of threat or adverse conditions have lifelong consequences for health outcomes. A basic assumption of this model was that developing organisms play a dynamic role in their own construction. Data are reviewed and new data are presented that elevated pCRH over the course of human gestation plays a fundamental role in the organization of the fetal nervous system, modifies birth phenotype (the timing of the onset of spontaneous labor and delivery), and influences developmental, temperamental and metabolic trajectories. Evidence for sex differences and conserved function across species is presented. Finally, a model is presented that proposes several pathways that pCRH can program risk for health and disease.

Prenatal Programming of Postnatal Susceptibility to Memory Impairments: A Developmental Double Jeopardy

In the study reported here, we examined the effects of fetal exposure to a synthetic stress hormone (synthetic glucocorticoids) on children's susceptibility to postnatal sociodemographic adversity. We recruited children who were born healthy and at term. Twenty-six had been treated with steroid hormones (glucocorticoids) during the prenatal period, and 85 had not. Only children exposed to both prenatal stress hormones and postnatal sociodemographic adversity showed impaired performance on standardized tests of memory function. The association was specific to long-term memory. General intellectual functioning and expressive language were not affected by fetal glucocorticoid exposure. Results were independent of maternal intelligence and maternal depression at the time of the study. These findings are consistent with a vulnerability-stress model: Prenatal exposure to synthetic stress hormones is associated with increased susceptibility to subsequent adversity, with consequences for cognitive functioning that persist 6 to 10 years after birth.

Fetal exposure to maternal depressive symptoms is associated with cortical thickness in late childhood

BACKGROUND

Maternal depression is one of the most common prenatal complications. The consequences of fetal exposure to maternal depression are poorly understood. The aim of this study is to examine the association between fetal exposure to maternal depressive symptoms and cortical thickness in children 6-9 years old.

METHODS

A prospective, longitudinal study of maternal depressive symptoms at 19, 25, and 31 weeks' gestation was followed by acquisition of a structural magnetic resonance imaging scan in 81 children (age, 86.1 ± 9.9 months).

RESULTS

Significant (p < .01) cortical thinning in children primarily in the right frontal lobes was associated with exposure to prenatal maternal depression. The strongest association was at 25 weeks' gestation; exposure to maternal depression at 25 gestational weeks was associated with cortical thinning in 19% of the whole cortex and 24% of the frontal lobes, primarily in the right superior, medial orbital, and frontal pole regions of the prefrontal cortex (p < .01). The significant association between prenatal maternal depression and child externalizing behavior (p < .05) was mediated by cortical thinning in prefrontal areas of the right hemisphere.

CONCLUSIONS

The pattern of cortical thinning in children exposed to prenatal maternal depression is similar to patterns in depressed patients and in individuals with risk for depression. Exposure to prenatal depression coupled with subsequent cortical thinning was associated with presence of externalizing behavior in preadolescent children and may be prodromal markers of risk for dysphoria. Vulnerability to prenatal influences at 25 gestational weeks may result from the enormous growth and dramatic structural changes in the nervous system.

Antenatal steroids: can we optimize the dose?

PURPOSE OF REVIEW

The beneficial effects of antenatal steroids in women at risk of preterm birth are evident. A dose of 24 mg appears sufficient, but there are insufficient data to recommend betamethasone or dexamethasone, a single steroid dose, the optimal interval between doses and repeated courses, the gestational age at which treatment is beneficial and the long-term effects of steroid treatment. This review addresses these aspects of antenatal steroid treatment.

RECENT FINDINGS

Although the 12-h and 24-h dosing intervals are equivalent with respect to prevention of respiratory distress syndrome, the former enables the completion of treatment in 50% more neonates delivered prematurely. Reducing the single steroid dose in patients at risk for premature birth reduces the associated maternal side effects. An inverse relationship has been demonstrated between the number of corticosteroid courses and foetal growth. The reduced size of exposed foetuses has been attributed to birth at earlier gestational ages and decreased foetal growth. Evidence suggests that antenatal exposure to synthetic glucocorticoids in term-born children has long-lasting effects, which may have important implications in the recommendation of steroids before elective caesarean at term.

SUMMARY

The short-term and long-term effects of the dosage regimen on the pregnant mother and foetus remain unclear.

Effects of antenatal corticosteroids on the hypothalamic-pituitary-adrenocortical axis of the fetus and newborn: experimental findings and clinical considerations

The hypothalamic-pituitary-adrenocortical (HPA) axis is a major neuroendocrine pathway that modulates the stress response. The glucocorticoid, cortisol, is the principal end product of the HPA axis in humans and plays a fundamental role in maintaining homeostasis and in fetal maturation and development. Antenatal administration of synthetic glucocorticoids (GCs) accelerates fetal lung maturation and has significantly decreased neonatal mortality and morbidity in infants born before 34 weeks of gestation. Exposure to excess levels of endogenous GCs and exogenous GCs (betamethasone and dexamethasone) has been shown to alter the normal development trajectory. The development and regulation of the fetal HPA axis is discussed and the experimental animal evidence presented suggests long-term adverse consequences of altered HPA function. The clinical data in infants exposed to GCs also suggest altered HPA axis function over the short term. The longer-term consequences of antenatal GC exposure on HPA axis function and subtler neurodevelopmental outcomes including adaptation to stress, cognition, behavior, and the cardiovascular and immune responses are poorly understood. Emerging clinical strategies and interventions may help in the selection of mothers at risk for preterm delivery who would benefit from existing or future formulations of antenatal GCs with a reduction in the associated risk to the fetus and newborn. Detailed longitudinal long-term follow-up of those infants exposed to synthetic GCs are needed.

Prenatal psychobiological predictors of anxiety risk in preadolescent children

Experimental animal models have demonstrated that one of the primary consequences of prenatal stress is increased fear and anxiety in the offspring. Few prospective human studies have evaluated the consequences of prenatal stress on anxiety during preadolescence. The purpose of this investigation is to determine the consequences of prenatal exposure to both maternal biological stress signals and psychological distress on anxiety in preadolescent children. Participants included 178 mother-child pairs. Maternal psychological distress (general anxiety, perceived stress, depression and pregnancy-specific anxiety) and biological stress signals were evaluated at 19, 25, and 31 gestational weeks. Anxiety was evaluated in the children at 6-9 years of age using the Child Behavior Checklist. Analyses revealed that prenatal exposure to elevated maternal cortisol, depression, perceived stress and pregnancy-specific anxiety was associated with increased anxiety in children. These associations remained after considering obstetric, sociodemographic and postnatal maternal psychological distress; factors that could influence child development. When all of the prenatal measures were considered together, cortisol and pregnancy-specific anxiety independently predicted child anxiety. Children exposed to elevated prenatal maternal cortisol and pregnancy-specific anxiety were at an increased risk for developing anxiety problems during the preadolescent period. This project identifies prenatal risk factors associated with lasting consequences for child mental health and raises the possibility that reducing maternal distress during the prenatal period will have long term benefits for child well-being.

Neurobehavioral risk is associated with gestational exposure to stress hormones

The developmental origins of disease or fetal programming model predict that early exposures to threat or adverse conditions have lifelong consequences that result in harmful outcomes for health. The maternal endocrine 'fight or flight' system is a source of programming information for the human fetus to detect threats and adjust their developmental trajectory for survival. Fetal exposures to intrauterine conditions including elevated stress hormones increase the risk for a spectrum of health outcomes depending on the timing of exposure, the timetable of organogenesis and the developmental milestones assessed. Recent prospective studies, reviewed here, have documented the neurodevelopmental consequences of fetal exposures to the trajectory of stress hormones over the course of gestation. These studies have shown that fetal exposures to biological markers of adversity have significant and largely negative consequences for fetal, infant and child emotional and cognitive regulation and reduced volume in specific brain structures.

Does soy-based infant formula cause ADHD? Update and public policy considerations

An earlier article hypothesized a relationship between soy-based infant formulas, manganese (Mn) neurotoxicity and symptoms of ADHD. In this update, more recent literature on ADHD, Mn and Mn neurotoxicity is reviewed, as well as the risks of Mn toxicity that may accompany ingestion of soy-based infant formula. The results of several critical studies are described, including rodent and primate models that demonstrate an association between ingestion of relatively high levels of Mn and: overactivity, disinhibition and inattention; stereotypes and disturbances of social relatedness; and alterations of dopamine D1 and D2 receptors and dopamine transporter in critical brain regions. Similar deficits have been shown in children with ADHD. In addition, ADHD-like symptoms of behavioral disinhibition were found to be correlated with Mn content in tooth enamel, apparently deposited at or before the fifth gestational month. The results are discussed in terms of their weight as a risk factor in ADHD, vis-à-vis compelling evidence of genetic, epigenetic and other environmental risk factors associated with the disorder, as well as the appropriateness of additional public policy decisions regarding the safety of soy formula.

Prescient human fetuses thrive

Fetal detection of adversity is a conserved trait that allows many species to adapt their early developmental trajectories to ensure survival. According to the fetal-programming model, exposure to stressful or hostile conditions in utero is associated with compromised development and a lifelong risk of adverse health outcomes. In a longitudinal study, we examined the consequences of prenatal and postnatal exposure to adversity for infant development. We found increased motor and mental development during the 1st year of life among infants whose mothers experienced congruent levels of depressive symptoms during and after pregnancy, even when the levels of symptoms were relatively high and the prenatal and postnatal environments were unfavorable. Congruence between prenatal and postnatal environments prepares the fetus for postnatal life and confers an adaptive advantage for critical survival functions during early development.

Prenatal maternal anxiety and early childhood temperament

The consequences of exposure to prenatal maternal anxiety for the development of child temperament were examined in a sample of 120 healthy, 2-year-old children. Prenatal maternal state and pregnancy-specific anxiety (PSA) were measured five times during pregnancy, and maternal state anxiety was measured again at 2 years post partum. Child temperament was measured at 2 years using the Early Childhood Behavior Questionnaire. The relationship between the trajectory of maternal anxiety across gestation and negative affectivity was evaluated using hierarchical linear growth curve modeling. Higher maternal PSA between 13 and 17 weeks of gestation was associated with increased negative temperament in the children. This association could not be explained by postnatal maternal anxiety, demographic, or obstetric factors. Prenatal maternal state anxiety was not associated with child temperament. These findings demonstrate that PSA early in gestation has a distinctive influence on the developing fetus.

Early childhood socioeconomic status is associated with circulating interleukin-6 among mid-life adults

It is proposed that socioeconomic conditions in early childhood effect immune programming, with poorer conditions resulting in adult phenotypes that are prone to inflammation. Recent evidence supports this possibility, showing an inverse association of childhood SES with adult markers of systemic inflammation. In this study, we further investigate this association, extending prior studies to include an examination of multiple indices of SES across distinct periods of childhood. Subjects were 112 men and women, 40-60 years of age (88.6% Caucasian). Childhood SES was indexed by a composite of three indicators of parental wealth (parental home and vehicle ownership, and number of bedrooms per child in the family home) averaged across 2 year periods of childhood between 1 and 18 years old. Higher adult serum concentrations of interleukin (IL)-6 were associated with lower SES in early childhood (years 1-2) (β=-.05, p<.05), associations that were independent of adult age, personal income, educational attainment, gender, race, body mass index, and physical activity. These associations support recent suggestions that the early environment may program immune phenotypes that contribute to disease risk.

Patterns of fetal heart rate response at ∼30 weeks gestation predict size at birth

There is evidence that fetal exposure to maternal stress is associated with adverse birth outcomes. Less is known about the association between fetal responses to a stressor and indicators of fetal maturity and developmental outcomes. The purpose of the present study was to determine whether fetal heart rate (FHR) patterns in response to a startling stimulus at ∼30 weeks of gestation were associated with gestational age at birth and birth weight. FHR was measured in 156 maternal-fetal dyads following a vibroacoustic stimulus. All pregnancies were singleton intrauterine pregnancies in English-speaking women who were primarily married, middle class, White and at least 18 years of age. Group-based trajectory modeling identified five groups of fetuses displaying distinctive longitudinal trajectories of FHR response to the startling stimulus. The FHR group trajectories were significantly associated with birth weight percentile (P < 0.01) even after controlling for estimated fetal weight at the time of assessment and parity, which are the known factors influencing birth weight (P < 0.01). Post hoc analyses indicated that two groups accounted for the association between FHR patterns and birth weight. The group (n = 23) with the lowest birth weight exhibited an immediate FHR deceleration followed by an immediate acceleration that does not recover. An FHR pattern characterized by immediate and fast acceleration to the peak and a slow discovery to baseline was associated with the highest birth weight. This is the first direct evidence showing that low birth weight and the resulting neurological consequences may have their origins in early fetal development.

Prenatal programming of human neurological function

The human placenta expresses the genes for proopiomelanocortin and the major stress hormone, corticotropin-releasing hormone (CRH), profoundly altering the "fight or flight" stress system in mother and fetus. As pregnancy progresses, the levels of these stress hormones, including maternal cortisol, increase dramatically. These endocrine changes are important for fetal maturation, but if the levels are altered (e.g., in response to stress), they influence (program) the fetal nervous system with long-term consequences. The evidence indicates that fetal exposure to elevated levels of stress hormones (i) delays fetal nervous system maturation, (ii) restricts the neuromuscular development and alters the stress response of the neonate, (iii) impairs mental development and increases fearful behavior in the infant, and (iv) may result in diminished gray matter volume in children. The studies reviewed indicate that fetal exposure to stress peptides and hormones exerts profound programming influences on the nervous system and may increase the risk for emotional and cognitive impairment.

Prenatal maternal stress programs infant stress regulation

OBJECTIVE

Prenatal exposure to inappropriate levels of glucocorticoids (GCs) and maternal stress are putative mechanisms for the fetal programming of later health outcomes. The current investigation examined the influence of prenatal maternal cortisol and maternal psychosocial stress on infant physiological and behavioral responses to stress.

METHODS

The study sample comprised 116 women and their full term infants. Maternal plasma cortisol and report of stress, anxiety and depression were assessed at 15, 19, 25, 31 and 36 + weeks' gestational age. Infant cortisol and behavioral responses to the painful stress of a heel-stick blood draw were evaluated at 24 hours after birth. The association between prenatal maternal measures and infant cortisol and behavioral stress responses was examined using hierarchical linear growth curve modeling.

RESULTS

A larger infant cortisol response to the heel-stick procedure was associated with exposure to elevated concentrations of maternal cortisol during the late second and third trimesters. Additionally, a slower rate of behavioral recovery from the painful stress of a heel-stick blood draw was predicted by elevated levels of maternal cortisol early in pregnancy as well as prenatal maternal psychosocial stress throughout gestation. These associations could not be explained by mode of delivery, prenatal medical history, socioeconomic status or child race, sex or birth order.

CONCLUSIONS

These data suggest that exposure to maternal cortisol and psychosocial stress exerts programming influences on the developing fetus with consequences for infant stress regulation.