Parental Precaution: Neurobiological Means and Adaptive Ends

Humans invest precious reproductive resources in just a few offspring, who remain vulnerable for an extended period of their lifetimes relative to other primates. Therefore, it is likely that humans evolved a rich precautionary psychology that assists in the formidable task of protecting offspring. In this review, we integrate precautionary behaviors during pregnancy and postpartum with the adaptive functions they may serve and what is known of their biological mediators, particularly brain systems motivating security and attachment. We highlight the role of reproductive hormones in (i) priming parental affiliation with young to incentivize offspring protection, (ii) focusing parental attention on cues of potential threat, and (iii) facilitating maternal defense against potentially dangerous conspecifics and predators. Throughout, we center discussion on adaptive responses to threats of disease, accident and assault as common causes of child mortality in the ancestral past

Stranger Danger: Parenthood and Child Presence Increase the Envisioned Bodily Formidability of Menacing Men

Due to altriciality and the importance of embodied capital, children’s fitness is contingent on parental investment. Injury suffered by a parent therefore degrades the parent’s fitness both by constraining reproduction and by diminishing the fitness of existing offspring. Due to the latter added cost, compared to non-parents, parents should be more cautious in hazardous situations, including potentially agonistic interactions. Prior research indicates that relative formidability is conceptualized in terms of size and strength. As erroneous under-estimation of a foe’s formidability heightens the risk of injury, parents should therefore conceptualize a potential antagonist as larger, stronger, and of more sinister intent than should non-parents; secondarily, the presence of one’s vulnerable children should exacerbate this pattern. We tested these predictions in the U.S. using reactions to an evocative vignette, administered via the Internet (Study 1), and in-person assessments of the facial photograph of a purported criminal, collected on the streets of Southern California (Study 2). As predicted, parents envisioned a potential antagonist to be more formidable than did non-parents. Significant differences between parents with children and non-parents without children in the threat that the foe was thought to pose (Study 1) were fully mediated by increases in estimated physical formidability

Economic and Health Predictors of National Postpartum Depression Prevalence: A Systematic Review, Meta-Analysis and Meta-Regression of 308 Studies from 56 Countries

Background: Postpartum depression (PPD) poses a major global public health challenge. PPD is the most common complication associated with childbirth and exerts harmful effects on children. Although hundreds of PPD studies have been published, we lack accurate global or national PPD prevalence estimates and have no clear account of why PPD appears to vary so dramatically between nations. Accordingly, we conducted a meta-analysis to estimate the global and national prevalence of PPD and a meta-regression to identify economic, health, social, or policy factors associated with national PPD prevalence. Methods: We conducted a systematic review of all papers reporting PPD prevalence using the Edinburgh Postnatal Depression Scale. PPD prevalence and methods were extracted from each study. Random effects meta-analysis was used to estimate global and national PPD prevalence. To test for country level predictors, we drew on data from UNICEF, WHO, and the World Bank. Random effects meta-regression was used to test national predictors of PPD prevalence. Findings: 291 studies of 296284 women from 56 countries were identified. The global pooled prevalence of PPD was 17.7% (95% confidence interval: 16.6–18.8%), with significant heterogeneity across nations (Q = 16,823, p = 0.000, I2 = 98%), ranging from 3% (2–5%) in Singapore to 38% (35–41%) in Chile. Nations with significantly higher rates of income inequality (R2 = 41%), maternal mortality (R2 = 19%), infant mortality (R2 = 16%), or women of childbearing age working ≥40 h a week (R2 = 31%) have higher rates of PPD. Together, these factors explain 73% of the national variation in PPD prevalence. Interpretation: The global prevalence of PPD is greater than previously thought and varies dramatically by nation. Disparities in wealth inequality and maternal-child-health factors explain much of the national variation in PPD prevalence

Oxytocin Receptor Gene (OXTR) and Father Support Interact to Predict Depressive Symptoms Postpartum

Postpartum depression (PPD) is a debilitating mental illness affecting approximately 13% of mothers after birth. Both genetic and psychosocial factors contribute to PPD risk, but very little is known about how these factors interact. We tested whether the rs53576 polymorphism in the oxytocin receptor (OXTR) gene accounts for variation in the impact of low social support as a risk factor for depression among mothers during the perinatal period. New mothers (N = 220) provided saliva or blood DNA samples and completed surveys assessing PPD symptoms and perceived social support. In a significant interaction, social support from the baby’s father predicted PPD symptoms to a greater extent among mothers with the GG compared to AG and AA genotypes. These results add to converging evidence that variation in OXTR rs53576 moderates the impact of the social environment on PPD

Response to “Cortisol in Human Milk: The Good, the Bad, or the Ugly?”

A response to Finken et al.\u27s Cortisol in Human Milk: The Good, the Bad, or the Ugly? , a critique of the authors\u27 previous article Cortisol in human milk predicts child BMI

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

Temporal Relation Between Pubertal Development and Peer Victimization in a Prospective Sample of US Adolescents

Peer victimization typically peaks in early adolescence, leading researchers to hypothesize that pubertal timing is a meaningful predictor of peer victimization. However, previous methodological approaches have limited our ability to parse out which puberty cues are associated with peer victimization because gonadal and adrenal puberty, two independent processes, have either been conflated or adrenal puberty timing has been ignored. In addition, previous research has overlooked the possibility of reverse causality—that peer victimization might drive pubertal timing, as it has been shown to do in non-human primates. To fill these gaps, we followed 265 adolescents (47% female) prospectively across three-time points (Mage: T1 = 9.6, T2 = 12.0, T3 = 14.4) and measured self-report peer victimization and self- and maternal-report of gonadal and adrenal pubertal development on the Pubertal Development Scale. Multilevel modeling revealed that females who were further along in adrenal puberty at age 9 were more likely to report peer victimization at age 12 (Cohen\u27s d = 0.25, p = .005). The relation between gonadal puberty status and peer victimization was not significant for either sex. In terms of the reverse direction, the relation between early peer victimization and later pubertal development was not significant in either sex. Overall, our findings suggest that adrenal puberty status, but not gonadal puberty status, predicted peer victimization in females, highlighting the need to separate gonadal and adrenal pubertal processes in future studies

Human Milk Omega-3 Fatty Acid Composition is Associated with Infant Temperament

There is growing evidence that omega-3 (n-3) polyunsaturated fatty-acids (PUFAs) are important for the brain development in childhood and are necessary for an optimal health in adults. However, there have been no studies examining how the n-3 PUFA composition of human milk influences infant behavior or temperament. To fill this knowledge gap, 52 breastfeeding mothers provided milk samples at 3 months postpartum and completed the Infant Behavior Questionnaire (IBQ-R), a widely used parent-report measure of infant temperament. Milk was assessed for n-3 PUFAs and omega-6 (n-6) PUFAs using gas-liquid chromatography. The total fat and the ratio of n6/n-3 fatty acids in milk were also examined. Linear regression models revealed that infants whose mothers’ milk was richer in n-3 PUFAs had lower scores on the negative affectivity domain of the IBQ-R, a component of temperament associated with a risk for internalizing disorders later in life. These associations remained statistically significant after considering covariates, including maternal age, marital status, and infant birth weight. The n-6 PUFAs, n-6/n-3 ratio, and total fat of milk were not associated with infant temperament. These results suggest that mothers may have the ability to shape the behavior of their offspring by adjusting the n-3 PUFA composition of their milk

Mothers’ Prenatal Distress Accelerates Adrenal Pubertal Development in Daughters

Human life history schedules vary, partly, because of adaptive, plastic responses to early-life conditions. Little is known about how prenatal conditions relate to puberty timing. We hypothesized that fetal exposure to adversity may induce an adaptive response in offspring maturational tempo. In a longitudinal study of 253 mother-child dyads followed for 15 years, we investigated if fetal exposure to maternal psychological distress related to children’s adrenarche and gonadarche schedules, assessed by maternal and child report and by dehydroepiandrosterone sulfate (DHEA-S), testosterone, and estradiol levels. We found fetal exposure to elevated maternal prenatal psychological distress predicted earlier adrenarche and higher DHEA-S levels in girls, especially first-born girls, and that associations remained after covarying indices of postnatal adversity. No associations were observed for boys or for gonadarche in girls. Adrenarche orchestrates the social-behavioral transition from juvenility to adulthood; therefore, significant findings for adrenarche, but not gonadarche, suggest that prenatal maternal distress instigates an adaptive strategy in which daughters have earlier social-behavioral maturation. The stronger effect in first-borns suggests that, in adverse conditions, it is in the mother’s adaptive interest for her daughter to hasten social maturation, but not necessarily sexual maturation, because it would prolong the duration of the daughter allomothering younger siblings. We postulate a novel evolutionary framework that human mothers may calibrate the timing of first-born daughters’ maturation in a way that optimizes their own reproductive success

The Dynamics of Stress and Fatigue Across Menopause: Attractors, Coupling, and Resilience

Objective: The objective of this study was to evaluate the regulatory dynamics between stress and fatigue experienced by women during the menopausal transition (MT) and early postmenopause (EPM). Fatigue and perceived stress are commonly experienced by women during the MT and EPM. We sought to discover relationships between these symptoms and to employ these symptoms as possible markers for resilience. Methods: Participants were drawn from the longitudinal Seattle Midlife Women\u27s Health Study. Eligible women completed questionnaires on 60+ occasions (annual health reports and monthly health diaries) (n = 56 women). The total number of observations across the sample was 4,224. STRAW+10 criteria were used to stage women in either in late reproductive, early or late transition, or EPM stage. Change values were generated for fatigue and stress and analyzed with a multilevel structural equation model; slopes indicate how quickly a person returns to homeostasis after a perturbation. Coupling of stress and fatigue was modeled to evaluate resilience, the notion of maintaining stability during change. Results: Eligible women were on average 35 years old (SD = 4.71), well educated, employed, married or partnered, and white. Fit indices suggested the model depicts the relationships of stress and fatigue (χ2(9 df) = 7.638, P = 0.57, correction factor = 4.9244; root mean square error of approximation (RMSEA) 90% CI = 0.000 ≤ 0.000 ≤ 0.032; comparative fit index (CFI) = 1.00). A loss in model fit across stages suggests that the four stages differed in their dynamics (χ2Δ(12 df) = 21.181, P = .048). All stages showed fixed-point attractor dynamics: fatigue became less stable over time; stress generally became more stable over time. Coupling relationships of stress on fatigue show evidence for shifts in regulatory relationships with one another across the MT. Conclusions: Results are suggestive of general dysregulation via disruptions to coupling relationships of stress and fatigue across the MT. Findings support a holistic approach to understanding symptoms and supporting women during the MT