Breaking the cycle: Psychological and social dimensions of pediatric functional gastrointestinal disorders

BACKGROUND

Functional gastrointestinal disorders (FGIDs) in children present with chronic symptoms like abdominal pain, diarrhea, and constipation without identifiable structural abnormalities. These disorders are closely linked to gut-brain axis dysfunction, altered gut microbiota, and psychosocial stress, leading to psychiatric comorbidities such as anxiety, depression, and behavioral issues. Understanding this bidirectional relationship is crucial for developing effective, holistic management strategies that address physical and mental health.

AIM

To examine the psychiatric impacts of FGIDs in children, focusing on anxiety and depression and their association with other neurodevelopmental disorders of childhood, such as attention-deficit/hyperactivity disorder, emphasizing the role of the gut-brain axis, emotional dysregulation, and psychosocial stress. Key mechanisms explored include neurotransmitter dysregulation, microbiota imbalance, central sensitization, heightening stress reactivity, emotional dysregulation, and symptom perception. The review also evaluates the role of family dynamics and coping strategies in exacerbating FGID symptoms and contributing to psychiatric conditions.

METHODS

A narrative review was conducted using 328 studies sourced from PubMed, Scopus, and Google Scholar, covering research published over the past 20 years. Inclusion criteria focused on studies examining FGID diagnosis, gut-brain mechanisms, psychiatric comorbidities, and psychosocial factors in pediatric populations. FGIDs commonly affecting children, including functional constipation, abdominal pain, irritable bowel syndrome, gastroesophageal reflux, and cyclic vomiting syndrome, were analyzed concerning their psychological impacts.

RESULTS

The review highlights a strong connection between FGIDs and psychiatric symptoms, mediated by gut-brain axis dysfunction, dysregulated microbiota, and central sensitization. These physiological disruptions increase children’s vulnerability to anxiety and depression, while psychosocial factors - such as chronic stress, early-life trauma, maladaptive family dynamics, and ineffective coping strategies - intensify the cycle of gastrointestinal and emotional distress.

CONCLUSION

Effective management of FGIDs requires a biopsychosocial approach integrating medical, psychological, and dietary interventions. Parental education, early intervention, and multidisciplinary care coordination are critical in mitigating long-term psychological impacts and improving both gastrointestinal and mental health outcomes in children with FGIDs.

A Qualitative Study of Naturally Living Parents and Child Oral Health: Omissions and Commissions

BACKGROUND

Oral health continues to be one of the most common and costly diseases in early childhood, and there is a need for further, innovative research.

PURPOSE

We explored the ways naturally living parents (those who embody the "natural" within their parenting ideology and behavior) navigated and perceived their children's oral health.

METHODS

Twelve participants who identified as being "naturally living parents" participated in semistructured interviews. Data were thematically analyzed, and findings were aligned to an omissions and commissions framework to exhibit the complexity of parent decision-making.

RESULTS

Parents performed distinct omissions, including omitting fluoride, sugar, and "toxins" to maintain their children's oral health. Parents talked about having a commitment to knowledge building to protect their children's oral health (e.g., ingredient label reading and increasing knowledge of "safe" ingredients). Findings also provide insight into how parents consider and trust health information and health care providers and ways they gather information relating to oral health.

CONCLUSIONS

Analysis indicated that although parents navigated both omissions and commissions, omissions were more overtly present. Compared to previous health research using this framework, omissions and commissions were not as clearly demarcated in relation to oral health. The results show that oral health is a complex interplay of omissions and commissions, and parents must navigate not only discrete elements that affect the oral health of their children but also how these are influenced by considerations including social well-being.Knowledge Transfer Statement:The study highlights the need for dentists and early childhood health professionals to consider the complex way some parents perceive, inform, and rationalize decisions regarding their children's oral health. There is a need for nuance when considering children's oral health and naturally living parenting, especially in relation to effectively communicating health information that fosters trust and is considerate of broader lifestyle and health factors.

The breadth and specificity of 18-month-old's infant-initiated interactions in naturalistic home settings

Infants actively initiate social interactions aiming to elicit different types of responses from other people. This study aimed to document a variety of communicative interactions initiated by 18-month-old Turkish infants from diverse SES (N = 43) with their caregivers in their natural home settings. The infant-initiated interactions such as use of deictic gestures (e.g., pointing, holdouts), action demonstrations, vocalizations, and non-specific play actions were coded from video recordings and classified into two categories as need-based and non-need-based. Need-based interactions were further classified as a) biological (e.g., feeding); b) socio-emotional (e.g., cuddling), and non-need-based interactions (i.e., communicative intentions) were coded as a) expressive, b) requestive; c) information/help-seeking; d) information-giving. Infant-initiated non-need-based (88%) interactions were more prevalent compared to need-based interactions (12%). Among the non-need-based interactions, 50% aimed at expressing or sharing attention or emotion, 26% aimed at requesting an object or an action, and 12% aimed at seeking information or help. Infant-initiated information-giving events were rare. We further investigated the effects of familial SES and infant sex, finding no effect of either on the number of infant-initiated interactions. These findings suggest that at 18 months, infants actively communicate with their social partners to fulfil their need-based and non-need-based motivations using a wide range of verbal and nonverbal behaviors, regardless of their sex and socio-economic background. This study thoroughly characterizes a wide and detailed range of infant-initiated spontaneous communicative bids in hard-to-access contexts (infants' daily lives at home) and with a traditionally underrepresented non-WEIRD population.

[Practice of portage groups]

Babywearing is of interest for the motor and relational development of the child, but also for the evolution of parental attachment and the way the father and/or mother view their relationship with their baby. The babywearing groups can be carried out within the framework of prevention with "all-round" families or with so-called fragile populations. The group presented here was set up by a psychomotrician; its actions are illustrated by the parents' feedback.

Early motor behavior of infants exposed to maternal mental health disorders - A South African perspective

INTRODUCTION

Over the past five decades the bulk of research on exposure to maternal mental health disorders and infant neurodevelopment has been generated in high-income countries. The current study included infants, residing in low-income communities in South Africa, born to mothers with a history of psychiatric disorders.

AIM

To assess the motor behavior of 10- to 20-week-old infants exposed to maternal mental health disorders, and a subgroup of infants with prenatal psychotropic medication exposure.

METHODS

The present study is a cross-sectional descriptive study, with a longitudinal subgroup analysis. General Movement Assessment (GMA), including the Motor Optimality Score-Revised (MOS-R), was used at 10-20 weeks corrected age to assess infant motor behavior.

RESULTS

The study included 112 infants. No significant difference (p = 0.523) was found on the MOS-R between infants exposed to maternal mental health disorders (n = 70) and the comparison group (n = 42). Both the exposed and comparison groups scored within the mildly reduced range on the MOS-R. No significant differences were found in a subgroup of infants with prenatal exposure to multi-class psychotropic medication (n = 17), mono-class psychotropic medication (n = 35) or valproate exposure (n = 10) (p > 0.1).

CONCLUSION

No association was found between exposure to maternal mental health disorders or exposure to psychotropic medication and infant motor behavior at 10-20 weeks post-term age on the MOS-R. Future research should focus on the contribution of exposure to specific classes and types of psychotropic medication on neurodevelopmental outcome of infants in larger cohorts.

Reasons mothers bedshare: A review of its effects on infant behavior and development

Bedsharing is controversial for nighttime caregiving in the U.S. today, as in most of the West. However, from the standpoint of evolutionary pediatrics, anthropology, and cultural psychology, bedsharing is not controversial at all, representing the context for human infant evolution and conferring a host of physiological benefits to the infant as well as the mother. In an effort to understand the rise in Western bedsharing in recent decades (and following Ball, 2002; McKenna & Volpe, 2007), Salm Ward (2015) systematically reviewed the literature on mother-infant bedsharing and identified ten reasons why mothers choose to bedshare: (1) breastfeeding, (2) comforting for mother or infant, (3) better/more sleep for infant or parent, (4) monitoring, (5) bonding/ attachment, (6) environmental reasons, (7) crying, (8) cultural or familial traditions, (9) disagree with danger, and (10) maternal instinct. The current paper offers the "review behind the review," highlighting the scientific evidence behind the reasons mothers give for their decision to bedshare, focusing on how mothers' decisions about infant sleep location influence infant behavior and development.

Exploring infant hip position and muscle activity in common baby gear and orthopedic devices

Infant positioning in daily life may affect hip development. While neonatal animal studies indicate detrimental relationships between inactive lower extremities and hip development and dysplasia, no research has explored infant hip biomechanics experimentally. This study evaluated hip joint position and lower extremity muscle activity of healthy infants in common body positions, baby gear, and orthopedic devices used to treat hip dysplasia (the Pavlik harness and the Rhino cruiserabduction brace). Surface electromyography(EMG) and marker-based motion capture recorded lower extremity muscle activity and kinematics of 22 healthy full-term infants (4.2±1.6 months, 13M/9F) during five conditions: Pavlik harness, Rhino brace, inward-facing soft-structured baby carrier, held in arms facing inwards, and a standard car seat. Mean filtered EMG signal, time when muscles were active, and hip position (angles) were calculated. Compared to the Pavlik harness, infants exhibited similar adductor activity (but lower hamstring and gluteus maximus activity) in the Rhino abduction brace, similar adductor and gluteus maximus activity (but lower quadriceps and hamstring activity) in the baby carrier, similar but highly variable muscle activity in-arms, and significantly lower muscle activity in the car seat. Hip position was similar between the baby carrier and the Pavlik harness. This novel infant biomechanics study illustrates the potential benefits of using inward-facing soft-structured baby carriers for healthy hip development and highlights the potential negative impact of using supine-lying container-type devices such as car seats for prolonged periods of time. Further study is needed to understand the full picture of how body position impacts infant musculoskeletal development.

Elimination communication contributes to a reduction in unexplained infant crying

The Normal Crying Curve refers to infants' unexplained crying from birth to a peak at about 6-8 weeks, and self-resolving by three months. However, it is known that infants signal their need to eliminate (micturate/defecate) through a variety of cues, including fussing and crying. Elimination Communication (EC) refers to a caregiver's nurturant response to infant cues, while also using timing, to gently and non-coercively cradle the infant in a supported, secure squatting position to eliminate. Such practices have been reported in ethnographic observations of hunter-gatherer care of infants, who cry less than minority world (Western) infants. We hypothesize that the current minority world practice of delayed toilet training and lack of caregiver response to elimination cues results in excessive, unexplained infant crying as infants eliminate in the constraints of diapers and in non-beneficial postures. As a corollary, we hypothesize that EC will reduce unexplained infant crying in the early months, perhaps even planating the Normal Crying Curve. To evaluate our hypothesis, we designed a pilot study to collect empirical data from mothers who practiced EC with their infants, tracking crying and fussing at Weeks 4, 6, 8 and 12 primarily utilizing a 24-hour Baby's Daily Diary. We computed baseline measures, compared our crying data with those from the literature, assessed our data for internal crying peaks, and used hierarchical multi-level modeling to evaluate cross-level interactions. We found that infants in our pilot study cried on average 50.3% less (p < 0.05), and up to 70.9% less in Week 6, compared to literature studies. Moreover, when we evaluated our data to seek out a significant crying peak across weeks, no such crying duration difference was found. Using hierarchical generalized linear modeling, we found that greater daily crying episodes predicted greater daily elimination opportunities. Shorter crying episodes predicted a greater number of daily elimination opportunities compared to longer crying episodes, especially among low baseline crying infants. Our results suggest that crying prompts caregivers to offer elimination opportunities, but when the crying continues, caregivers may try other behavioral responses, such as feeding. Additionally, our results suggest that with the practice of EC, unexplained infant crying may be significantly reduced and warrant future research with an expanded sample. If the practice of EC indeed planates the Normal Crying Curve, then such results will have a significant impact on our understanding of unexplained infant crying.

Positioning and baby devices impact infant spinal muscle activity

Infant positioning in daily life, particularly in relation to active neck and back muscles, may affect spinal development, psychosocial progression, and motor milestone achievement. Yet the impact of infant body position on muscle activity is unknown. The objective of this study was to evaluate neck and back muscle activity of healthy infants in common positions and baby devices. Healthy full-term infants (n = 22, 2-6 months) participated in this experimental study. Daily sleep and positioning were reported by caregivers. Cervical paraspinal and erector spinae muscle activity was measured using surface electromyography (EMG) in five positions: lying prone, lying supine, held in-arms, held in a baby carrier, and buckled into a car seat. Mean filtered EMG signal and time that muscles were active were calculated. Paired t-tests were used to compare positions to the prone condition. Caregivers reported that infants spent 12% of daily awake time prone, 43% in supine-lying baby gear, and 44% held in-arms or upright in a baby carrier. Infants exhibited highest erector spinae activity when prone, and lowest cervical paraspinal muscle activity in the car seat. No differences were found between in-arms carrying and babywearing. This first evaluation of the muscle activity of healthy infants supports the importance of prone time in infants' early spinal development because it promotes neck and back muscle activity. Carrying babies in-arms or in baby carriers may also be beneficial to neck muscle development, while prolonged time spent in car seats or containment devices may be detrimental to spinal development.

Gender role ideology in mothers and fathers: Relation with parent-child aggression risk longitudinally

BACKGROUND

The existing literature is dominated by models of parent-child aggression (PCA) risk using maternal samples, thereby limiting insight into factors that contribute to fathers' PCA risk. Protective factors that can affect PCA risk within the mother-father dyad at the cultural level are also often overlooked.

OBJECTIVE

The current study examined the potential positive role of gender ideologies on maternal and paternal PCA risk over time, considering both individual and partner effects on PCA risk.

PARTICIPANTS AND SETTING

Participants were 150 couples, with primiparous mothers and their male partners identified from a larger study of PCA risk.

METHODS

The study employed a longitudinal design with three waves. Participants were first assessed in mothers' third trimester of pregnancy and re-assessed when their child was 6 months and 18 months. Dyads reported their gender role attitudes prenatally and PCA risk across time.

RESULTS

Egalitarian gender role ideologies related to lower PCA risk for both mothers and fathers prenatally. At 6 months, neither mothers' nor fathers' gender role ideologies related to PCA risk but by 18 months, fathers' gender role beliefs predicted their PCA risk whereas mother's gender role beliefs only marginally predicted their PCA risk. Maternal egalitarian gender ideologies significantly predicted fathers' lower PCA risk at 6 months.

CONCLUSIONS

These findings suggest less traditional gender roles may contribute to lower PCA risk in parents particularly prior to childbirth. Therefore, future work is needed to further consider the evolving interconnectedness within couples in their PCA risk over time.

Evaluation of selected cardiopulmonary and perceived exertion responses to four infant carrying methods utilised by African Mothers

Various infant carrying methods (ICMs) are utilised for childcare. Effects of these ICMs on the cardiopulmonary system are not known. This study evaluated cardiopulmonary and perceptual responses to four ICMs (back, front, side and in-arms) among 30 young females (18-35 years) while walking with a 6 kg simulated infant. Diastolic blood pressure (BP) responses were significantly different (p = .009) across the four ICMs, with the back ICM eliciting highest response. Heart rate, respiratory rate and systolic BP responses were not significantly different (p > .05) across the ICMs. Participants perceived the in-arms ICM as the most exerting. Body weight (p = .036) and body mass index (BMI) (p = .011) significantly correlated with systolic BP responses during the side ICM while age significantly (p = .036) correlated with heart rate changes during the in-arms ICM. Back ICM may pose more risk of diastolic BP dysfunctions. Increased body weight and BMI result in decreased systolic BP responses. IMPACT STATEMENT What is already known on this subject? Infant carrying (IC) has been associated with increased energy cost, biomechanical changes and musculoskeletal injuries. There is paucity of data on the cardiopulmonary responses to IC. What do the results of this study add? Back ICM resulted in higher responses in diastolic blood pressure. During the side ICM, participants' systolic BP decreased with increasing body weight and BMI values. Increased age resulted to decreased heart rate responses during the in-arms ICM. What are the implications of these findings for clinical practice and/or further research? There is need for effective monitoring of the cardiopulmonary parameters during IC tasks, especially among women with cardiopulmonary dysfunctions. Women with diastolic dysfunctions should be discouraged from utilising the back ICM. It is necessary for further studies to evaluate infant carrying-related cardiopulmonary responses relative to various components of IC practices, including weight of infant, maternal anthropometric characteristics and duration of IC tasks during each infant carrying method.

IGNORING CHILDREN'S BEDTIME CRYING: THE POWER OF WESTERN-ORIENTED BELIEFS

Ignoring children's bedtime crying (ICBC) is an issue that polarizes parents as well as pediatricians. While most studies have focused on the effectiveness of sleep interventions, no study has yet questioned which parents use ICBC. Parents often find children's sleep difficulties to be very challenging, but factors such as the influence of Western approaches to infant care, stress, and sensitivity have not been analyzed in terms of ICBC. A sample of 586 parents completed a questionnaire to investigate the relationships between parental factors and the method of ICBC. Data were analyzed using structural equation modeling. Latent variables were used to measure parental stress (Parental Stress Scale; J.O. Berry & W.H. Jones, 1995), sensitivity (Situation-Reaction-Questionnaire; Y. Hänggi, K. Schweinberger, N. Gugger, & M. Perrez, 2010), Western-oriented parental beliefs (Rigidity), and children's temperament (Parenting Stress Index; H. Tröster & R.R. Abidin). ICBC was used by 32.6% (n = 191) of parents in this study. Parents' Western-oriented beliefs predicted ICBC. Attitudes such as feeding a child on a time schedule and not carrying it out to prevent dependence were associated with letting the child cry to fall asleep. Low-sensitivity parents as well as parents of children with a difficult temperament used ICBC more frequently. Path analysis shows that parental stress did not predict ICBC. The results suggest that ICBC has become part of Western childrearing tradition.

Infant carrying methods: Correlates and associated musculoskeletal disorders among nursing mothers in Nigeria

Infant carrying is an integral part of the mothering occupation. Paucity of data exists on its correlates and associated musculoskeletal injuries. In this study, factors and musculoskeletal injuries associated with infant carrying were investigated in 227 nursing mothers, using a structured questionnaire. 77.1% utilised the back infant carrying methods (ICM). Maternal comfort was the major factor influencing participants' (37.4%) choices of ICMs. Infant's age (p = .000) and transportation means (p = .045) were significantly associated with ICMs. Low back pain (82.8%) and upper back pain (74.9%) were the most reported musculoskeletal discomforts associated with ICMs, especially among women who utilised back ICM. Back ICM is predominantly used by nursing mothers. Impact statement Infant carrying has been associated with increased energy cost and biomechanical changes. Currently, there is a paucity of data on infant carrying-related musculoskeletal injuries. In this study, investigating factors and musculoskeletal injuries associated with infant carrying, the results showed that back infant carrying method is predominantly used by nursing mothers. Age of the infant and mothers' means of transportation were determinant factors of infant carrying methods. Among the several reported infant carrying-related musculoskeletal disorders, low back and upper back pain were the most prevalent, especially among women who utilised the back infant carrying method. There is need for women's health specialists to introduce appropriate ergonomic training and interventions on infant carrying tasks in order to improve maternal musculoskeletal health during the childbearing years and beyond. Further experimental studies on the effects of various infant carrying methods on the musculoskeletal system are recommended.

Baby carriers: a comparison of traditional sling and front-worn, rear-facing harness carriers

The baby sling is a traditional baby carrier in Asia and the front-worn harness carriers are adapted in modern society. We compared the baby sling with front-worn harness carrier in terms of the physiological responses of the baby caregiver. Ten females (aged 23-32 years) and 10 males (aged 23-35 years) were recruited to participate in this study. Each subject was asked to carry two different weight baby dummies (7 and 10 kg) using three different baby carriers. The electromyography (EMG), shoulder tactile pressure, skin temperatures as well as heart rate were measured during baby carrying. The traditional baby sling and the two front-worn harness carriers showed little differences in EMG activities, shoulder tactile pressure and exercise intensity. Carrying two different weighted baby dummies caused significant differences in EMG and shoulder tactile pressure. Based on the findings of this study, recommendations about the improved baby carrier design are proposed. Practitioner Summary: This study compared traditional sling and front-worn harness baby carriers using caregivers' physiological responses including electromyography, shoulder tactile pressure, skin temperature and heart rate. Differences found between the carriers provide valuable information for baby carrier design and recommendations for the baby-carrying task.

Using liminality to understand mothers’ experiences of long-term breastfeeding: ‘Betwixt and between’, and ‘matter out of place’

Breastmilk is widely considered as the optimum nutrition source for babies and an important factor in both improving public health and reducing health inequalities. Current international/national policy supports long-term breastfeeding. UK breastfeeding initiation rates are high but rapidly decline, and the numbers breastfeeding in the second year and beyond are unknown. This study used the concept of liminality to explore the experiences of a group of women breastfeeding long-term in the United Kingdom, building on Mahon-Daly and Andrews. Over 80 breastfeeding women were included within the study, which used micro-ethnographic methods (participant observation in breastfeeding support groups, face-to-face interviews and online asynchronous interviews via email). Findings about women’s experiences are congruent with the existing literature, although it is mostly dated and from outside the United Kingdom. Liminality was found to be useful in providing insight into women’s experiences of long-term breastfeeding in relation to both time and place. Understanding women’s experience of breastfeeding beyond current usual norms can be used to inform work with breastfeeding mothers and to encourage more women to breastfeed for longer.

Parent-child bed-sharing: The good, the bad, and the burden of evidence

The practice of parent and child sharing a sleeping surface, or 'bed-sharing', is one of the most controversial topics in parenting research. The lay literature has popularized and polarized this debate, offering on one hand claims of dangers, and on the other, of benefits - both physical and psychological - associated with bed-sharing. To address the scientific evidence behind such claims, we systematically reviewed 659 published papers (peer-reviewed, editorial pieces, and commentaries) on the topic of parent-child bed-sharing. Our review offers a narrative walkthrough of the many subdomains of bed-sharing research, including its many correlates (e.g., socioeconomic and cultural factors) and purported risks or outcomes (e.g., sudden infant death syndrome, sleep problems). We found general design limitations and a lack of convincing evidence in the literature, which preclude making strong generalizations. A heat-map based on 98 eligible studies aids the reader to visualize world-wide prevalence in bed-sharing and highlights the need for further research in societies where bed-sharing is the norm. We urge for multiple subfields - anthropology, psychology/psychiatry, and pediatrics - to come together with the aim of understanding infant sleep and how nightly proximity to the parents influences children's social, emotional, and physical development.

A twin study of breastfeeding with a preliminary genome-wide association scan

Breastfeeding has been an important survival trait during human history, though it has long been recognized that individuals differ in their exact breastfeeding behavior. Here our aims were, first, to explore to what extent genetic and environmental influences contributed to the individual differences in breastfeeding behavior; second, to detect possible genetic variants related to breastfeeding; and lastly, to test if the genetic variants associated with breastfeeding have been previously found to be related with breast size. Data were collected from a large community-based cohort of Australian twins, with 3,364 women participating in the twin modelling analyses and 1,521 of them included in the genome-wide association study (GWAS). Monozygotic (MZ) twin correlations (r MZ = 0.52, 95% CI 0.46-0.57) were larger than dizygotic (DZ) twin correlations (r DZ = 0.35, 95% CI 0.25-0.43) and the best-fitting model was the one composed by additive genetics and unique environmental factors, explaining 53% and 47% of the variance in breastfeeding behavior, respectively. No breastfeeding-related genetic variants reached genome-wide significance. The polygenic risk score analyses showed no significant results, suggesting breast size does not influence breastfeeding. This study confers a replication of a previous one exploring the sources of variance of breastfeeding and, to our knowledge, is the first one to conduct a GWAS on breastfeeding and look at the overlap with variants for breast size.

Epigenetics and Allostasis

The purpose of this review article is to show how sociological theories of criminal behavior can be illuminated by drawing on insights from epigenetics and the concept of allostasis. The burgeoning field of epigenetics has the promise of burying whatever lingering fears about “genetic determinism” some criminologists may still have. Epigenetics concerns itself with environmental conditions that regulate the transcript and expression of genes and is a discipline that can be of enormous use to criminology because it emphasizes the plasticity of the human genome. We know that the brain is amazingly plastic and a major target for epigenetic modification. All stimuli must be funneled to the brain before a behavioral response is initiated. Because the brain and the systems of stress response—the hypothalamic–pituitary–adrenal (HPA) axis and the autonomic nervous system (ANS)—are designed for plasticity, they are highly vulnerable to epigenetic and allostatic changes when exposed to environmental experiences that are evolutionarily novel. The downregulation of systems of behavioral control (dopamine/serotonin ratios and hyporeactive HPA axis and ANS) has frequently and strongly shown to be related to criminal behavior. This article outlines how these changes occur, and why they occur most frequently in deprived environments. We believe that an understanding of how criminogenic environments “get into” the person molecularly can plug gaps in poverty- and control-based theories of criminal behavior. We present this article in the spirit of biosocial criminology which avers that the more we come to understand and appreciate the biology of behavior, the more we realize the importance of the environment.

Evolutionary perspectives on mother-infant sleep proximity and breastfeeding in a laboratory setting

Human maternal and infant biology likely coevolved in a context of close physical contact and some approximation of frequent, "infant-initiated" breastfeeding. Still, mothers and infants commonly sleep apart from one another in many western societies, indicating a possible "mismatch" between cultural norms and infant biology. Here we present data from a 3-night laboratory-based study that examines differences in mother-infant sleep physiology and behavior when mothers and infants sleep together on the same surface (bedsharing) and apart in separate rooms (solitary). We analyze breastfeeding frequency and interval data from the first laboratory night (FN) for 52 complementary breastfeeding mothers and infants (26 total mother-infant pairs), of which 12 pairs were routine bedsharers (RB) and 14 were routine solitary sleepers (RS). RB infants were 12.0 ± 2.7 (SD) weeks old; RS infants were 13.0 ± 2.4 weeks old. On the FN, RB mother-infant pairs (while bedsharing) engaged in a greater number of feeds per night compared to RS (while sleeping alone) (P < 0.001). RB also showed lower intervals (min) between feeds relative to RS (P < 0.05). When we evaluated data from all three laboratory nights (n = 36), post hoc, RB breastfed significantly more often (P < 0.01) and showed a trend towards lower intervals between feeds (P < 0.10). Given the widely known risks associated with little or no breastfeeding, the demonstrated mutually regulatory relationship between bedsharing and breastfeeding should be considered in future studies evaluating determinants of breastfeeding outcomes.

Infant crying and sleeping: helping parents to prevent and manage problems

This article summarizes the current understanding of infant crying and sleeping problems, together with the implications of this understanding for services and research, with a focus on the first months of infancy.