Infants' Biological Sensitivity to the Effects of Maternal Social Support: Evidence Among Mexican American Families.

The identification of infants who are most susceptible to both negative and positive social environments is critical for understanding early behavioral development. This study longitudinally assessed the interactive effects of infant vagal tone (respiratory sinus arrhythmia; RSA) and maternal social support on behavioral problems and competence among 322 low-income Mexican American mother-infant dyads (infants: 54.1% female) and explored sex differences. Infant RSA was calculated from resting HR data at 6 weeks of age. Mothers reported on general social support, partner support, and family support at 6 months, and infant behavioral problems and competence at 1 year. Two-way interactions (RSA × support source) were evaluated to predict behavioral problems and competence, adjusting for covariates. Results indicated higher competence among infants with lower RSA whose mothers reported higher general support or higher partner support. Interactive effects on behavior problems of RSA with maternal partner or family support were only found for female infants: Girls with higher RSA showed more behavior problems when mothers reported low support, but fewer problem levels in the context of high support. Our results suggest that infant RSA is an important moderator of the effects of the early social environment on early development.

Respiratory sinus arrhythmia: Modeling longitudinal change from 6 weeks to 2 years of age among low-income Mexican Americans.

Parasympathetically-mediated heart rate variability (HRV), commonly indexed via respiratory sinus arrhythmia (RSA), is theorized to support the physiological regulation of emotion; however, little is known about the trajectory of change in resting RSA across early development among high-risk populations for whom emotion regulation is crucial. This study characterized resting RSA change from 6 weeks to 2 years of age among 312 low-income Mexican American infants. RSA was assessed longitudinally at 6, 12, 18, 24, 52, 78, and 104 weeks of age. On average, resting RSA increased as infants aged, and this change accelerated over time. There was significant variance between infants in resting RSA at 6 weeks of age, and in the slope, and acceleration of resting RSA change. Intraclass correlation among infants' resting RSA measures was minimal, indicating that resting RSA may not be "trait-like" during infancy. Results characterize early RSA development among a high-risk sample, which can inform theoretical understanding of the development of emotional, and behavioral self-regulation in a high-risk population, as well as efforts to promote wellbeing across early childhood.

Family Support and Family Negativity as Mediators of the Relation between Acculturation and Postpartum Weight in Low-Income Mexican-Origin Women.

BACKGROUND: Obesity presents a significant health concern among low-income, ethnic minority women of childbearing age. PURPOSE: The study investigated the influence of maternal acculturation, family negativity, and family support on postpartum weight loss among low-income Mexican-origin women. METHODS: Low-income Mexican-origin women (N=322; 14% born in the U.S.) were recruited from a prenatal clinic in an urban area of the Southwest U.S. Acculturation was assessed during a prenatal home visit (26-38 weeks gestation), and post-birth family support and general family negativity were assessed at 6 weeks postpartum. Objective maternal weight measures were obtained at five time points across the first postpartum year. RESULTS: Higher acculturation predicted higher family support and family negativity. Higher family support predicted decreasing weight across the first postpartum year, and higher family negativity predicted higher weight at 6 weeks postpartum and increasing weight across the first postpartum year. In combination, family negativity and support mediated the impact of acculturation on postpartum weight gain. CONCLUSIONS: Cultural and family-related factors play a significant role in postpartum weight gain and loss for low-income Mexican-origin women.

Maternal acculturation and the growth of impoverished Mexican American infants.

OBJECTIVE: Identification of early life risk factors that predispose low-income Hispanic children to obesity is critical. For low-income Mexican American mothers, the cultural context may influence maternal experience and behaviors relevant to infant weight and growth. METHODS: In a longitudinal study of 322 low-income Mexican American mother-infant dyads, linear growth modeling examined the relation of maternal acculturation to infant weight gain across the first year and evaluated birth outcomes, breastfeeding, and maternal BMI as mediators. RESULTS: There was a high prevalence (36% >95th percentile) of infants with obesity at 1 year. Higher maternal acculturation was associated with lower birth weight, higher infant weight at 6 weeks, and a lower prevalence of breastfeeding. Mediation analyses supported formula-feeding as a mediator of the relation between higher maternal acculturation and an increasing slope of infant weight gain across the first year. CONCLUSIONS: Breastfeeding may have measurable benefits for Mexican American child obesity status in this high-risk population, particularly among those with more acculturated mothers.

Social support coping style predicts women's cortisol in the laboratory and daily life: the moderating role of social attentional biases.

BACKGROUND AND OBJECTIVES: Social stress and associated coping responses can profoundly influence women's stress physiology and health. Implicit social attentional biases can also influence psychological and physiological stress responses. The purpose of this study was to explore whether a coping style characterized by greater use of social support predicts indices of cortisol activity in laboratory and daily life contexts among female university students. We hypothesized that the relation of this coping style to cortisol activity would be moderated by women's attentional biases. METHODS: Seventy-four women (Mage = 19.44, range: 17.8-27.8, 64% White) completed an interpersonal stress task and an attentional bias task in the lab, along with a self-report coping inventory. Participants provided five saliva samples during the lab protocol, followed by three saliva samples per day for three consecutive weekdays. Outcome measures included cortisol response to lab tasks (AUCg), diurnal cortisol slope, diurnal AUCg, and cortisol awakening response (CARi). RESULTS: A coping style characterized by greater use of social support predicted lower lab AUCg and lower, flatter average diurnal cortisol slope for women with attentional avoidance compared to women with attentional vigilance (ps < .05). CONCLUSIONS: Responding to stress by using social support is linked to lower cortisol responses to social stress and diurnal cortisol activity for women with implicit avoidance of social threat cues.

Prediction of Postpartum Weight in Low-Income Mexican-Origin Women From Childhood Experiences of Abuse and Family Conflict.

OBJECTIVES: The postpartum period represents a crucial transition period in which weight gain or loss can affect lifetime obesity risk. This study examined the prevalence of obesity and the influence of childhood abuse and family conflict on postpartum weight among low-income Mexican-origin women. Depressive symptoms and partner support were evaluated as mediators. METHODS: At a prenatal assessment, low-income Mexican-origin women (N = 322; mean [SD] age, 27.8 [6.5]) reported on childhood abuse and family conflict. Weight was measured 7 times between 6 weeks and 2 years postpartum and calculated as body mass index. Regression and growth models were used to estimate the impact of childhood abuse, childhood family conflict, partner support, and depressive symptoms on weight and weight change. RESULTS: Higher family conflict predicted higher weight across the first (ß = .12; p = .037) and second (ß = .16; p = .012) postpartum years. Family conflict (ß = .17; p = .018) and low partner support (ß = -.16; p = .028) also predicted increasing weight in the first year. Partner support partially mediated the effect of childhood abuse on weight change in the first year (p = .031). Depressive symptomatology mediated the effects of childhood abuse and family conflict on weight status in the second year (abuse: p = .005; conflict: p = .023). CONCLUSIONS: For low-income Mexican-origin women with a history of childhood abuse or high family conflict, depression and low partner support may be important targets for obesity prevention efforts in the postpartum period.

Economic Stress and Cortisol Among Postpartum Low-Income Mexican American Women: Buffering Influence of Family Support.

Low-income Mexican American women experience significant health disparities during the postpartum period. Contextual stressors, such as economic stress, are theorized to affect health via dysregulated cortisol output. However, cultural protective factors including strong family support may buffer the impact of stress. In a sample of 322 low-income Mexican American women (mother age 18-42; 82% Spanish-speaking; modal family income $10,000-$15,000), we examined the interactive influence of economic stress and family support at 6 weeks postpartum on maternal cortisol output (AUCg) during a mildly challenging mother-infant interaction task at 12 weeks postpartum, controlling for 6-week maternal cortisol and depressive symptoms. The interaction significantly predicted cortisol output such that higher economic stress predicted higher cortisol only among women reporting low family support. These results suggest that family support is an important protective resource for postpartum Mexican American women experiencing elevated economic stress.

Effects of prenatal factors and temperament on infant cortisol regulation in low-income Mexican American families.

Prenatal psychosocial exposures can significantly affect infant health and development. Infants with higher temperamental negativity are theorized to be more susceptible to environmental exposures. We evaluated the interaction of prenatal maternal exposures and infant temperamental negativity to predict infant cortisol response to mildly challenging mother-infant interaction tasks. Participants included 322 Mexican American mother-infant dyads (mother age 18-42; 82% Spanish-speaking; modal family income $10,000-$15,000). Mothers reported depressive symptoms and social support prenatally and infant temperamental negativity at 6 weeks postpartum. Salivary cortisol was collected from infants before and after mother-infant interaction tasks at 12 weeks. Higher prenatal maternal depressive symptoms and lower social support predicted higher cortisol among infants with higher temperamental negativity. Higher infant temperamental negativity predicted an increase in maternal distress and a decrease in social support from prenatal to 12 weeks postpartum. Interactive influences of maternal social-contextual factors and infant temperament may influence the development of infant neurobiological regulation and promote or strain maternal and infant adaptation over time.