Prenatal maternal cortisol measures predict learning and short-term memory performance in 3- but not 5-month-old infants

Prenatal Learning and Memory: Review on the Impact of Exposure

BACKGROUND

Prenatal Learning is a topic still debated for its existence, although the concept is well known since ancient times.

OBJECTIVE

The present review highlights the impact of various stimuli on learning and memory in prenatal and postnatal life.

METHODS

For review, various articles from preclinical and clinical studies providing early pieces of evidence of prenatal learning to date were included based on the relevancy of the databases, namely, Scopus, Pubmed, and Google Scholar.

RESULTS

Learning is the process of acquiring skills/ preferences/ habits from the experiences of the exposures of the past. These exposures are the stimuli, which help in categorizing learning into associated or nonassociated learning. The stimuli of adults related to auditory, gustatory, olfactory, visual, touch, etc. are also accessible to the prenatal life in utero either directly or indirectly through the mother. The effects of these stimuli are remarkable during prenatal life and can be seen clearly in infants. These stimuli play an important role in prenatal learning and contribute to neuronal development. The present review summarizes the pieces of evidence for each of these types of learning & their impact on the ex utero life, a futuristic view & the scope of understanding prenatal learning. The review also elucidates the factors affecting prenatal learning.

CONCLUSION

Studies from clinical and preclinical studies reflected the impacts of several aspects of an infant's life and the memory created during prenatal life was found to be most likely carried on to postnatal life.

Maternal prenatal cortisol trajectories predict accelerated growth in infancy

Higher maternal cortisol in pregnancy has been linked to childhood obesity. Much of the previous research has been limited in that cortisol in pregnancy is only measured at one time-point, precluding the ability to examine critical timing effects of prenatal maternal cortisol. To fill this gap, this longitudinal study measured maternal plasma cortisol at 15, 19, 25, and 31 weeks of pregnancy, and assessed infant body mass index percentile (BMIP)1 at birth, 3, 6, 12, and 24 months in 189 mother-infant pairs. Three distinct patterns of maternal cortisol in pregnancy (typical, steep, and flat trajectories) were identified using general growth mixture modeling (GGMM)2 and then used to predict child growth patterns using multilevel modeling. Infants of mothers who had flat cortisol trajectories, characterized by relatively high cortisol in early gestation that plateaus by mid-gestation, experienced more rapid increases in BMIP from birth to 6 months, and had higher BMIPs at 3 and 6 months, than infants whose mothers had the typical slow cortisol rise over gestation, or steep (rapidly accelerating) trajectories. These results suggest that it is not just the total amount of maternal cortisol in pregnancy that shapes early infant growth, but instead the timing and trajectory of prenatal cortisol exposure. To better understand the early origins of obesity risk, future research is needed to investigate the factors that shape mothers' prenatal cortisol trajectories.

"Does your baby watch TV?": The associations between at-home TV watching and laboratory challenge cortisol are different for young infants and their mothers

This longitudinal study examined associations between at-home TV watching and the biological stress response (cortisol) during a laboratory infant cognitive challenge task in 240 3- and 5-month infants and their mothers. Cortisol levels were lower in mothers of 5-month-old infants whose infants were exposed to TV at home, compared to mothers of infants that were not TV-exposed. Cortisol patterns were different across three laboratory sampling intervals for 3-month-old infants as a function of TV watching, revealing a sharp increase in laboratory cortisol only for infants who were exposed to TV at home. In contrast, there was no effect of TV exposure in 5-month-old infants' cortisol. Infant temperament and demographic measures were included as control variables in regression models to predict maternal and infant cortisol. At 3 months, for the T3 cortisol sampling interval, and at 5 months across all three sampling intervals, maternal cortisol levels were significantly predicted by infant TV exposure after accounting for variance due to these control variables. Our findings show the strong influence of the infant TV-exposure factor in the biological stress response of mothers of young infants, and suggest that infant TV exposure may influence self-regulation in 3-month-old infants.

Social Network and Behavioral Synchrony Influences On Maternal and Infant Cortisol Response

This study examined the contributions of mothers' social network stability and mother-infant behavioral synchrony on cortisol response in infants and their mothers during separation. The quality and stability of mothers' social network system and mother-infant bond have both been shown to affect infant neuroendocrine response. Yet, no studies have directly addressed how these two forms of social relationships might differentially affect infants' and mothers' neuroendocrine responses during separation. First-time mothers (N = 133) and their 3-month-old infants participated in the study. Maternal social network stability, mother-infant behavioral synchrony, and mother and infant cortisol response during an infant challenge task were assessed. Behavioral synchrony accounted for significant variance in infants' cortisol response, and after adjusting for synchrony, mothers' network stability measures did not explain variance in infant cortisol. Social network stability, but not synchrony, accounted for significant variance in mothers' cortisol response. These results demonstrate that, when mothers and infants experience brief separation, the quality of their bond is associated with a lower stress response for infants; but for mothers, it is the longevity of her social relationships outside of the mother-infant relationship context that is associated with her lower stress response.

Characterizing prenatal maternal distress with unique prenatal cortisol trajectories

OBJECTIVE

It is widely assumed that glucocorticoids represent a primary mechanism through which exposure to adversity and maternal psychological distress shape prenatal developmental trajectories of both mother and fetus. However, despite repeated investigations and the fact that prenatal cortisol has been reliably linked to developmental outcomes, the empirical evidence supporting an association between prenatal cortisol and maternal distress is scarce. In this study, a novel approach to assessing links between maternal prenatal psychological distress and gestational cortisol profiles, general growth mixture modeling (GGMM), was applied.

METHOD

Measures of pregnancy anxiety, perceived stress, and state anxiety and depressive symptoms as well as plasma samples (for determination of cortisol) were collected from 250 women 4 times during pregnancy.

RESULTS

Using GGMM, 3 cortisol trajectory groups were identified, including a typical group (n = 199) that exhibited the expected steady increase in cortisol throughout gestation, a steep group (n = 31) displaying an accelerated increase in cortisol over the course of pregnancy relative to the typical group, and a flat group (n = 20) with relatively higher cortisol levels early in pregnancy that plateaued in midgestation. Women reporting the highest distress scores exhibited trajectories expected to be associated with the least optimal developmental outcomes (flatter trajectories characterized by relatively higher levels early in gestation and lower levels late in gestation).

CONCLUSIONS

These findings suggest that psychological distress during pregnancy is associated with unique prenatal cortisol profiles and support further examination of this link, to enable continued evaluation of a plausible biological pathway by which maternal psychological distress programs fetal development. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Gene × Environment Interaction in Developmental Disorders: Where Do We Stand and What's Next?

Although the field of psychiatry has witnessed the proliferation of studies on Gene × Environment (G×E) interactions, still limited is the knowledge we possess of G×E interactions regarding developmental disorders. In this perspective paper, we discuss why G×E interaction studies are needed to broaden our knowledge of developmental disorders. We also discuss the different roles of hazardous versus self-generated environmental factors and how these types of factors may differentially engage with an individual's genetic background in predicting a resulting phenotype. Then, we present examplar studies that highlight the role of G×E in predicting atypical developmental trajectories as well as provide insight regarding treatment outcomes. Supported by these examples, we explore the need to move beyond merely examining statistical interactions between genes and the environment, and the motivation to investigate specific genetic susceptibility and environmental contexts that drive developmental disorders. We propose that further parsing of genetic and environmental components is required to fully understand the unique contribution of each factor to the etiology of developmental disorders. Finally, with a greater appreciation of the complexities of G×E interaction, this discussion will converge upon the potential implications for clinical and translational research.