Background: Unwanted intrusive thoughts of intentionally harming one's infant (intrusive harm thoughts) are common distressing experiences among postpartum mothers and fathers. Aim: To understand infant crying as a stimulus for intrusive harm thoughts and associated emotional responses in prepartum and postpartum mothers and fathers in response to infant cry. Method: Following completion of self-report measures of negative mood and anger, prepartum (n = 48) and postpartum (n = 44) samples of mother and father pairs completed 10 minutes of listening to audio-recorded infant crying. Post-test questionnaires assessed harm thoughts, negative emotions, urges to comfort and flee, and thoughts of shaking as a soothing or coping strategy. Results: One quarter of prepartum and 44% of postpartum parents reported intrusive infant-related harm thoughts following crying. Mothers and fathers did not differ in the likelihood of reporting harm thoughts, nor in the number of thoughts reported. Women reported more internalizing emotions compared with men. Hostile emotions were stronger among postpartum parents, and parents reporting harm thoughts. All parents reported strong urges to comfort the infant. Urges to flee were stronger among parents who reported harm thoughts. The likelihood of using infant shaking as a soothing or coping strategy was minimally endorsed, albeit more strongly by fathers and parents who also reported harm thoughts. Conclusions: In response to crying, harm thoughts are common and are associated with hostile emotions, urges to flee, and increased thoughts of using infant shaking. Reassuringly, the number of participants considering infant shaking as a strategy for soothing or for coping with a crying infant was low.

Animal models of early postnatal mother–infant interactions have highlighted the importance of tactile contact for biobehavioral outcomes via the modification of DNA methylation (DNAm). The role of normative variation in contact in early human development has yet to be explored. In an effort to translate the animal work on tactile contact to humans, we applied a naturalistic daily diary strategy to assess the link between maternal contact with infants and epigenetic signatures in children 4–5 years later, with respect to multiple levels of child-level factors, including genetic variation and infant distress. We first investigated DNAm at four candidate genes: the glucocorticoid receptor gene, nuclear receptor subfamily 3, group C, member 1 (NR3C1), μ-opioid receptor M1 (OPRM1) and oxytocin receptor (OXTR; related to the neurobiology of social bonds), and brain-derived neurotrophic factor (BDNF; involved in postnatal plasticity). Although no candidate gene DNAm sites significantly associated with early postnatal contact, when we next examined DNAm across the genome, differentially methylated regions were identified between high and low contact groups. Using a different application of epigenomic information, we also quantified epigenetic age, and report that for infants who received low contact from caregivers, greater infant distress was associated with younger epigenetic age. These results suggested that early postnatal contact has lasting associations with child biology.

Parent–child relationships have long-term effects on health, particularly later inflammation and depression. We hypothesized that these effects would be mediated by later romantic partner relationships and elevated stressors in young adulthood, helping promote chronic, low grade, inflammation as well as depressive symptoms, and driving their covariation. It has been proposed recently that youth experiencing harsher parenting may also develop a stronger association between inflammation and depressive symptoms in adulthood and altered effects of stressors on outcomes. In the current investigation, we test these ideas using an 18-year longitudinal study of N = 413 African American youth that provides assessment of the parent–child relationship (at age 10), pro-inflammatory cytokine profile and depressive symptoms (at age 28), and potential mediators in early young adulthood (assessed at ages 21 and 24). As predicted, the effect of harsher parent–child relationships (age 10) on pro-inflammatory state and increased depressive symptoms at age 28 were fully mediated through young adult stress and romantic partner relationships. In addition, beyond these mediated effects, parent–child relationships at age 10 moderated the concurrent association between inflammation and depressive symptoms, as well as the prospective association between romantic partner relationships and inflammation, and resulted in substantially different patterns of indirect effects from young adult mediators to outcomes. The results support theorizing that the association of depression and inflammation in young adulthood is conditional on earlier parenting, and suggest incorporating this perspective into models predicting long-term health outcomes.

This study aimed to determine whether supine sleep-positioned infants have delayed motor skills at age 4 and 6 months, and if delays are associated with decreased exposure to prone position. One 4 and one 6-month-old sample of healthy infants born at term were recruited. Motor assessments included the Peabody Developmental Motor Scale (PDMS) and Alberta Infant Motor Scale (AIMS). Parents completed an infant behavior diary for 3 consecutive days. Seventy-one 4-month-old infants were assessed (38 males; mean age 4.4mo, standard deviation [SD] 0.2). Mean motor scores were close to normative standards (AIMS 47.7, SD19.6; PDMS gross motor quotient [GMQ] 96.3, SD 6.5; PDMS fine motor quotient [FMQ] 99.2, SD4.8). No infant scored below cut-off values used to identify motor delay. Milestones less likely to be achieved included extended arm support in prone, hands to feet in supine, and sitting with arm support. Exposure to ‘tummy time’ while awake was correlated with AIMS scores (r=0.38, p<0.01). Fifty 6-month-old infants were assessed (21 males; mean age 6.4mo, SD0.4). Mean scores were shifted down for all scales, and as much as 1SD for PDMS (AIMS 44.5, SD 21.6; PDMS GMQ 85.7, SD7.6; PDMS FMQ 88.9, SD9.0). Only 22% of 6-month-olds could sit without arm support versus 50% expected in a normative sample. Remarkably, 22% of our sample exhibited gross motor delays (quotient<78). Tummy time (awake) was significantly associated with the AIMS (r=0.64) and PDMS GMQ (r=0.55) and FMQ (r=0.33) quotients, even after adjusting for confounders. Typically developing infants who were sleep-positioned in supine had delayed motor development by age 6 months, and this was significantly associated with limited exposure to awake prone positioning. This has important implications for interpreting motor assessments of infants at risk and for preventing inappropriate referrals.

I argue that in the first three months, crying is primarily a behavioral state rather than a signal and that its properties include prolonged and unsoothable crying bouts as part of normal development. However, these normal properties trigger Shaken Baby Syndrome, a form of child abuse that does not easily fit an adaptive infanticide analysis.

To understand how the ‘caregiving context’ could affect responses to procedural pain, the authors sought to determine whether (1) the combined effects of sweet taste and holding (caregiving contact) were greater than the effects of either alone, (2) any combined effects were additive or interactive, and (3) the interventions had similar effects on behavioral (crying and facial activity) and physiological (heart rate, vagal tone) responses to the heel-stick procedure in newborn infants in a randomized two-factorial intervention trial. Eighty-five normally developing newborn infants were studied with a mean gestational age of 39.4 weeks on the 2nd or 3rd day of life. Infants were randomized in blocks of eight to receive (1) no holding and water taste (control participants), (2) no holding and sucrose taste (sucrose group), (3) holding and water taste (holding group), or (4) holding and sucrose taste (holding and sucrose group). Crying was reduced significantly by taste and holding, and the interventions combined additively. Facial activity was only significantly reduced by holding. For physiological measures, the interventions interacted with each other and preintervention levels to reduce heart rate and lower vagal tone more during the procedure in infants in whom heart rate and vagal tone were higher before intervention. Consequently, sweet taste and holding interventions combined in complex ways when acting on different behavioral and physiological response systems to modify stressful pain experiences. The results suggest that providing a caregiving context when painful procedures are performed may be a simple and practical method of reducing pain experience in infants, and that no one measure captures these effects.