Kortisol i modersmjölken: positivt associerat med kvinnors relationsaggressivitet, negativt associerat med barns emotionell anpassning

Emotionell och social anpassning förklaras till del av biologi men också av mammors kortisolnivåer strax före, under och strax efter förlossningen. För kvinnor förklaras höga kortisolhalter sannolikt relationsaggressivitet och vårdnadskonflikter. Barn som drabbas av mammor med höga kortisolhalter tappar det som kallas emotionell och social anpassning, vilket även hämmar kognitiv utveckling. Genom att medvetandegöra sig om sin egen biologiska set-up samt addera kunskap, exempelvis om hur kortisol påverkar individen. Kvinnors kan alltså träna på att resonera - utbyta idéer genom språk - och därmed bättra på sin impulskontroll. Det gynnar barnen. 29 sidor.

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Emotionell och social anpassning förklaras till del av biologi men också av mammors kortisolnivåer strax före, under och strax efter förlossningen. Sannolikt påverkar det även mamma-barnrelationen under tidig uppväxt.

Kortisolär ett hormon som finns i kroppen och som behövs för att vi ska fungera normalt. Det är till exempel ökning av kortisol som gör att vi vaknar på morgnarna. Men, precis som med allt annat gäller att lagom är bäst. Om man har för mycket av varan: då blir effekterna negativa.

Goleman (2006) menar t ex. att ökade kortisolnivåer stänger av aktiviteter i hippocampus för att istället aktivera amygdala - emotionscentret. Därmed ändras vårt beteende, från rationellt tänkande till flight-fight. När vi är i flight-fight mode kan vi inte diskutera eller resonera - utbyta idéer genom språk - och som regel leder det till argumentation eller polemik - verbalt krig.

Mammors höga kortisolhalter förklarar sannolikt det som kallas relationsaggressivitet (Crick och Grotpeter, 1995; Hyde, 2005) som sannolikt förklarar kvinnors vårdnadskonflikter.

Barn som drabbas av mammors relationsaggressivitet tappar det som kallas emotionell och social anpassning, vilket ökar risken för antisocialt beteende (Calkins & Keane, 2009; Moffitt et al. 2001; Vieno et al. 2009: Österberg, 2004).

Impulskontroll, som är del av vår arts exekutiva funktioner, är nyckeln till fungerande social interaktion för utvecklas genom träning (Ardila, 2008; Barkley, 2001). Pinker (2011) menar att det handlar om att tämja djävulen inom sig. Kvinnors kan alltså träna på att resonera - utbyta idéer genom språk - och därmed bättra på sin impulskontroll. Det gynnar barnen.

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Appendix:

Labad, Javier; Vilella, Elisabet; Reynolds, Rebecca M.; Sans, Teresa; Cavallé, Pere; Valero, Joaquín; Alonso, Pino; Menchón, José Manuel; Labad, Antonio; Gutiérrez-Zotes, Alfonso. (2011). Increased morning adrenocorticotrophin hormone (ACTH) levels in women with postpartum thoughts of harming the infant. Psychoneuroendocrinology, Vol 36(6), 924-928.

Introduction: Some postpartum women experience intrusive thoughts of harming the infant. The hypothalamic-pituitary-adrenal (HPA) axis, which has been linked to postpartum depression, may play a role in the aetiology of postpartum thoughts of harming the infant. We aimed to study whether HPA axis hormones measured early postpartum are related to postpartum intrusive thoughts. Method: 132 women who delivered a child at a university hospital participated in a follow-up study with visits at 2-3 days postpartum and 8th week postpartum. Participants were assessed for trait anxiety, social support, peripartum or postpartum anxiety or depression, stressful life events and obstetric variables including perinatal complications and lactation. Postpartum thoughts of harming the infant were assessed with a semi-structured interview. Serum cortisol, and plasma CRH and ACTH levels were measured within 48 h postpartum at 8-9 AM. A logistic regression was performed to explore the relationship between clinical variables, hormonal measures and postpartum intrusive thoughts. Results: Patients with postpartum thoughts of harming the infant had, when compared to those women without intrusive thoughts, higher ACTH levels (7.59 pmol/L vs 5.09 pmol/L, p < 0.05) without significant differences in CRH or cortisol levels. In the logistic regression analysis, adjusted for breast-feeding and psychopathological status, only ln ACTH was associated with the presence of postpartum thoughts of harming the infant (OR = 5.2, CI 95% 1.2-22.6, p = 0.029). No other clinical variables were associated with postpartum intrusive thoughts. Conclusions: Our study suggests that a dysregulation of the hypothalamic-pituitary-adrenal axis may play a role in the aetiology of postpartum thoughts of harming the infant.

Handlin, Linda; Jonas, Wibke; Petersson, Maria; Ejdebäck, Mikael; Ransjö-Arvidson, Anna-Berit; Nissen, Eva; Uvnäs-Moberg, Kerstin. (2009). Effects of sucking and skin-to-skin contact on maternal ACTH and cortisol levels during the second day postpartum—Influence of epidural analgesia and oxytocin in the perinatal period. Breastfeeding Medicine, Vol 4(4), 207-220.

Background and Aims: In this study we made a detailed analysis of the mothers' release pattern of adrenocorticotropic hormone (ACTH) and cortisol during a breastfeeding session during the second day postpartum and related these patterns to maternal oxytocin levels as well to the duration of sucking and the duration of skin-to-skin contact before sucking the breast. Furthermore, we investigated if epidural analgesia and oxytocin administration during and after labor influenced the release pattern of ACTH and cortisol. Methods: Sixty-three primiparae were included in the study. Fourteen received oxytocin intramuscularly postpartum, nine received oxytocin infusion, 14 received epidural analgesia combined with oxytocin infusion, and six received epidural analgesia alone. Twenty mothers did not receive any of these medical interventions. Blood samples were analyzed for ACTH and cortisol by enzyme-linked immunoassay. Results: Both ACTH and cortisol levels fell significantly during the breastfeeding session. A significant negative relationship was found between oxytocin and ACTH levels, but not between oxytocin and cortisol levels. A positive and significant relationship was found between ACTH and cortisol levels. The duration of skin-to-skin contact before onset of sucking was significantly and negatively associated with lower cortisol levels, but not with ACTH levels. Cortisol levels differed significantly between mothers having received epidural analgesia with and without oxytocin. Conclusions: Breastfeeding is associated with a decrease of ACTH and cortisol levels. Skin-to-skin contact contributes to this effect. ACTH correlated negatively with the duration of sucking and with median oxytocin levels, whereas cortisol levels correlated inversely with the duration of skin-to-skin contact preceding sucking, suggesting a partial dissociation between the mechanisms regulating ACTH and cortisol release. In addition, medical interventions in connection with birth influence the activity of the hypothalamic-pituitary-adrenal axis 2 days after birth.

Kudielka, Brigitte M.; Hellhammer, D. H.; Wüst, Stefan. (2009). Why do we respond so differently? Reviewing determinants of human salivary cortisol responses to challenge. Psychoneuroendocrinology, Vol 34(1), 2-18.

Stress and stress-related health impairments are major problems in human life and elucidating the biological pathways linking stress and disease is of substantial importance. However, the identification of mechanisms underlying a dysregulation of major components of the stress response system is, particularly in humans, a very challenging task. Salivary cortisol responses to diverse acute challenge paradigms show large intra- and interindividual variability. In order to uncover mechanisms mediating stress-related disorders and to potentially develop new therapeutic strategies, an extensive phenotyping of HPA axis stress responses is essential. Such a research agenda depends on substantial knowledge of moderating and intervening variables that affect cortisol responses to different stressors and stimuli. The aim of this report is, therefore, to provide a comprehensive summary of important determinants of, in particular, human salivary cortisol responses to different kinds of laboratory stimuli including acute psychosocial stress as well as pharmacological provocation procedures. This overview demonstrates the role of age and gender, endogenous and exogenous sex steroid levels, pregnancy, lactation and breast-feeding, smoking, coffee and alcohol consumption as well as dietary energy supply in salivary cortisol responses to acute stress. Furthermore, it briefly summarizes current knowledge of the role of genetic factors and methodological issues in terms of habituation to repeated psychosocial stress exposures and time of testing as well as psychological factors, that have been shown to be associated with salivary cortisol responses like early life experiences, social factors, psychological interventions, personality as well as acute subjective-psychological stress responses and finally states of chronic stress and psychopathology.

Nishitani, Shota; Miyamura, Tsunetake; Tagawa, Masato; Sumi, Muneichiro; Takase, Ryuta; Doi, Hirokazu; Moriuchi, Hiroyuki; Shinohara, Kazuyuki. (2009). The calming effect of a maternal breast milk odor on the human newborn infant. Neuroscience Research, Vol 63(1), 66-71.

We examined the effects of the odors from mother's milk, other mother's milk and formula milk on pain responses in newborns undergoing routine heelsticks. Forty-eight healthy infants were assigned to four groups, an own mother's breast milk odor group (Own MM), another mother's breast milk odor group (Other MM), a formula milk odor group (Formula M) and a control group. To assess infant distress in response to the heelsticks, their crying, grimacing and motor activities were recorded during the experiment as behavioral indices of the pain response. After the heelstick, the behavioral indices of the Own MM group were lower than those of other groups. By contrast, the Other MM and Formula M groups showed no significant changes compared with the Control group. We also measured salivary cortisol concentration as a biochemical index in Control and Own MM infants before and after heelstick. After the heelstick, the level of salivary cortisol was significantly increased in Control infants, but not in Own MM infants. These results suggest that pain is relieved in human newborns when they are exposed to odors from their mother's milk.

Oberlander, Tim F.; Grunau, Ruth; Mayes, Linda; Riggs, Wayne; Rurak, Dan; Papsdorf, Michael; Misri, Shaila; Weinberg, Joanne. (2008). Hypothalamic-pituitary-adrenal (HPA) axis function in 3-month old infants with prenatal selective serotonin reuptake inhibitor (SSRI) antidepressant exposure. Early Human Development, Vol 84(10), 689-697.

Background: Prenatal exposure to stress and selective serotonin reuptake inhibitors (SSRIs) alter hypothalamic–pituitary–adrenal (HPA) stress reactivity in offspring, however, the effects of combined exposure to HPA activity in human infants is unknown. Objective: To examine HPA basal levels and stress responsiveness in 3-month olds with prenatal exposure to SSRIs. Methods: Salivary cortisol levels in infants of SSRI treated mothers ( n = 31, mean exposure 230.2 ± 72.2 days) were compared with non-SSRI exposed ( n = 45) infants in response to a challenge (infant-controlled habituation task) and under basal conditions in the late afternoon/early evening. Mode of feeding, to account for possible postnatal drug exposure via breast milk, as well as measures of pre and postnatal maternal mood, were included as covariates. Results: Lower post-stress cortisol levels were observed in non-SSRI exposed/non-breastfed infants compared with non-SSRI exposed infants who were breastfed at 3 months of age. Stress reactivity patterns among SSRI exposed infants did not differ with mode of feeding. The cortisol reactivity slope (CRS) was significantly lower among non-SSRI exposed non-breastfed infants compared with non-SSRI exposed breastfed infants. Early evening basal cortisol levels were lower in SSRI exposed infants than in non-SSRI exposed infants, controlling for maternal mood and mode of feeding. Postnatal SSRI exposure (infant SSRI drug levels) via breast milk was not associated with stress or basal cortisol levels. Total cortisol, reflected by the AUC measure, did not differ significantly between exposure groups. Conclusions: Prenatal SSRI exposure altered HPA stress response patterns and reduced early evening basal cortisol levels. Stress challenge HPA response differences only became apparent when the moderating effect of method of feeding was accounted for. These findings suggest an early “programming” effect of antenatal maternal mood, prenatal SSRI exposure and postnatal maternal care giving on the HPA system.

Stenius, Fredrik; Theorell, Tores; Lilja, Gunnar; Scheynius, Annika; Alm, Johan; Lindblad, Frank. (2008). Comparisons between salivary cortisol levels in six-months-olds and their parents. Psychoneuroendocrinology, Vol 33(3), 352-359.

Background: There is a close relation between the psychosocial environment of the infant--including the perception of maternal behaviour--and cortisol levels of the infant. One previous study has also demonstrated a correlation between mother and infant mean cortisol levels. In this study, this relation was further explored, also including father cortisol levels. Methods: Saliva cortisol samples were collected from 51 six-months-olds and their parents on the same day in the morning, afternoon and evening. Analyses were performed with a radioimmunoassay technique. All mothers were at home with their child at this age and 47/51 mothers were breast feeding. Results: Strong correlations were found between mother and child levels on all sampling occasions whereas weaker correlations were found between father and child levels and only in the afternoon and the evening samples. There was also a strong relation between waking up/bedtime-difference in mother and child and a weaker relation between the corresponding measure in father and child. Conclusions: The stronger mother-infant than father-infant cortisol level correlations probably mirror that mother and infant not only have genetic similarities but also have been exposed to similar environmental conditions to a higher degree than father and infant.

Glynn, Laura M.; Davis, Elysia Poggi; Schetter, Christine Dunkel; Chicz-DeMet, Aleksandra; Hobel, Calvin J.; Sandman, Curt A. (2007). Postnatal maternal cortisol levels predict temperament in healthy breastfed infants. Early Human Development, Vol 83(10), 675-681.

Background: The implications of the biologically active elements in breast milk for the breastfed infant are largely unknown. Animal models suggest that ingestion of glucocorticoids during the neonatal period influences fear behavior and modifies brain development. Aims: To determine the association between postnatal maternal cortisol levels and temperament in breastfed infants. Study Design: The relation between maternal cortisol and infant temperament was examined in breastfed and formula-fed infants. Plasma cortisol was used as a surrogate measure for breast milk cortisol levels (plasma and milk levels are correlated in the 0.6 to 0.7 range; [Patacchioli FR, Cigliana G, Cilumbriello A, Perrone G, Capri O, Alemà GS, et al. Maternal plasma and milk free cortisol during the first 3 days of breast-feeding following spontaneous delivery or elective cesarean section. Gynecologic and Obstetric Investigations 1992;34:159-163.]. If exposure to elevated cortisol levels during infancy influences temperament, then a relation between the two should be found among the breastfed infants, but not among the formula-fed infants. Subjects: Two hundred fifty-three two-month-old infants and their mothers. Outcome Measures: Fearful temperament assessed with the Infant Behavior Questionnaire [Garstein MR, Rothbart MK. Studying infant temperament via the revised infant behavior questionnaire. Infant Behavior and Development 2003;26:64-86]. Results: Among the breastfed infants, higher maternal cortisol levels were associated with reports of increased infant fear behavior (partial r = 0.2; p < 0.01). This relation did not exist among the formula-fed infants. Negative maternal affect at the time of assessment did not account for the positive association in the breastfed group. Conclusions: The findings are consistent with our proposal that exposure to cortisol in breast milk influences infant temperament. Biologically active components in breast milk may represent one avenue through which the mother shapes the development of the human infant during the postnatal period.

Mezzacappa, E. Sibolboro; Endicott, J. (2007). Parity mediates the association between infant feeding method and maternal depressive symptoms in the postpartum. Archives of Women's Mental Health, Vol 10(6), 259-266.

Maternal depression is the most common complication of the postpartum, having devastating and long lasting effects on mother and infant. Lactation is associated with attenuated stress responses, especially that of cortisol, and the lactogenic hormones, oxytocin and prolactin, are associated with anti-depressant and anxiolytic effects. These associations suggest that breast-feeding may decrease maternal depressive symptoms, yet empirical results have been conflicting. Recent findings have indicated that parity may mediate the association between breast-feeding and stress response. Because a decreased stress response is associated with a decreased risk for depression, parity may also mediate the association between infant feeding method and depressive symptoms. Specifically, the benefits of breast-feeding may appear in multiparous but not primiparous mothers. In the present study, data drawn from a national sample of primiparous and multiparous mothers were examined for possible associations between infant feeding method and depressive symptoms, as assessed by the Center for Epidemiological Survey-Depression scale (CES-D). After controlling for several possible confounding variables, breast-feeding by multiparas was associated with significantly decreased odds of having depression compared with bottle-feeders (OR = 0.41, CI 0.19-0.87, p = 0.02); however, no risk reduction from breast-feeding was evident among primiparas. The results support a parity-mediated association between lactation and maternal depressive symptoms. The results provide a reason for earlier conflicting findings, present new research avenues, and suggest possible clinical approaches.

Tu, Mai Thanh. (2007). Hypothalamic-pituitary-adrenal activity in postpartum mothers: The role of infant feeding type, parity, salience of stressor and sociodemographic factors. Dissertation Abstracts International: Section B: The Sciences and Engineering, Vol 68(3-B), 1473.

Hypothalamic-pituitary-adrenal (HPA) responsiveness to stress is generally blunted in lactating rats, except during situations of pup endangerment, suggesting an important role of salience of stressor in stress response during lactation. Conversely, in women, breastfeeding is associated with reduced HPA responses to physical stress and perceived stress. Yet, HPA responses to a standardized speech and arithmetic task (Trier Social Stress Test, TSST) are not blunted in breastfeeding mothers. Interestingly, greater number of children (parity) increases maternal experience which can enhance responsiveness to child-related stressors. To our knowledge, no study to date has investigated the impact of infant feeding type and parity on basal and reactive HPA secretion in human mothers using an emotional stressor evoking threat to a child. Furthermore, no study has investigated the effect of return of ovarian activity, sleep disturbances, education and income even though these variables are function of infant feeding type. Therefore, in STUDY (1) we assessed the impact of infant feeding type (breast vs. bottle) and parity (primiparous, first-time mother vs. multiparous, second-time mother) on diurnal cortisol secretion. Then, in STUDY (2) we verified whether infant feeding upon waking up would affect awakening cortisol response (ACR), an endogenous stimulation of HPA axis. Finally, in STUDY (3) we investigated the impact of infant feeding type, parity and salience of stressor on salivary cortisol and (sympathetic) alpha-amylase responses to laboratory-induced (exogenous) stressors that were either related or unrelated to child well-being (a home-made emotional film evoking lost and hurt children or the TSST). Breastfeeding mothers presented lower estradiol concentrations, more frequent nocturnal sleep interruptions and higher education and income. We found that greater basal cortisol secretion in multiparous bottlefeeding compared to multiparous breastfeeding mothers at awakening and 4PM, when simultaneous child and infant cares are the most prominent. No impact of breastfeeding was found on ACR. Finally, among multiparous mothers, following both the TSST and the emotional film, cortisol responsiveness in bottlefeeding was greater than in breastfeeding mothers. Alpha-amylase responses were similar across groups. Interestingly, income played a role in the stability of diurnal cycle, and possibly of ACR across days, but not on laboratory-induced stress responses. No effect of other secondary variables was detected. In conclusion, in this dissertation, we show for the first time that during child-related stress, multiparity accentuates the reduction in basal and reactive HPA activity associated with breastfeeding. Furthermore, the evidence of potential association between high socioeconomic indices and healthier HPA function represent a new avenue for implementing support programs for mothers during the highly emotional and stressful period following childbirth.

Tu, Mai Thanh; Lupien, Sonia J.; Walker, Claire-Dominique. (2006). Diurnal salivary cortisol levels in postpartum mothers as a function of infant feeding choice and parity. Psychoneuroendocrinology, Vol 31(7), 812-824.

Daily stress and sleep deprivation can influence the diurnal pattern of cortisol, which normally consists of high morning levels and a gradual decline throughout the day. While most individuals have consistent declining cortisol concentrations over days, others display either flat or inconsistent profiles. Postpartum mothers experience considerable home demands and sleep deprivation, yet, breastfeeding mothers perceive lower stress and reduced negative mood states compared to bottlefeeders. On the other hand, multiparity (having more than one child) is associated with reduced steepness in diurnal cortisol decline. Interestingly, no study to date has investigated the diurnal cortisol pattern and its stability across days in postpartum women as a function of their choice of infant feeding and parity. In this study, we measured salivary cortisol at four different time points during the day, on two non-consecutive days in first-time (primiparous) and second-time (multiparous) mothers at 5-20 weeks postpartum who were exclusively breastfeeding or bottlefeeding, and in non-postpartum mothers of young children (1-6 years). Among multiparous mothers, we found that cortisol levels in those who were bottlefeeding were higher than in breastfeeding mothers at both awakening and 1600h. This effect remained significant after controlling for individual differences related to infant feeding choice, such as estradiol levels, education and income. No effect of infant feeding choice on cortisol concentrations was observed in primiparous mothers. While a consistent decline across days was common, some mothers presented a flat or inconsistent profile, a profile that was not associated with infant feeding choice or parity. Importantly, mothers with consistent declining profiles had the highest household income. Our findings suggest that although breastfeeding might promote a tighter regulation of diurnal basal cortisol secretion, in particular for multiparous mothers who are likely to be exposed to greater home demands and maternal responsibilities, some aspects of socioeconomic status such as income can also play a significant role in the stability of diurnal cortisol secretion across days.

Tu, M. T.; Lupien, S. J.; Walker, C.-D. (2006). Multiparity reveals the blunting effect of breastfeeding on physiological reactivity to psychological stress. Journal of Neuroendocrinology, Vol 18(7), 494-503.

Rat studies show that hypothalamic-pituitary-adrenal (HPA) responsiveness to physical and emotional stressors is attenuated during lactation, although situations evoking pup endangerment can supersede this phenomenon. In the human population, blunted cortisol responses are seen in primiparous breastfeeding compared to bottlefeeding mothers following physical stress, but not after psychosocial stress. It is currently unknown whether stressor salience (child-related versus nonrelated stressor) has a differential effect on cortisol reactivity as a function of infant feeding choice and whether HPA responses to stress could be modified by parity. We investigated the impact of infant feeding type and maternal parity on salivary cortisol and alpha-amylase response to stress in 5-20-week postpartum mothers using exposure to the Trier Social Stress Test (TSST) and to an emotional film evoking threats to a child. Analyses show that alpha-amylase responses were similar in all groups and for both types of stress, suggesting that sympathetic reactivity was independent of infant feeding type and parity. By contrast, cortisol response was affected by these variables. In primiparous mothers, cortisol reactivity to psychological stressors did not vary as a function of infant feeding type while, among multiparous mothers, breastfeeding was associated with reduced responsiveness to the TSST and child-related stressor. We speculate that changes in neural mechanisms occurring as a result of pregnancy and lactation and that modulate the HPA axis in women might be exacerbated with multiple repeats of the pregnancy/lactation period. This would serve to 'desensitise' stress circuits and reduce the overall stress-induced cortisol secretion after multiple births.

Krpan, Katherine M.; Coombs, Rosemarie; Zinga, Dawn; Steiner, Meir; Fleming, Alison S. (2005). Experiential and hormonal correlates of maternal behavior in teen and adult mothers. Hormones and Behavior, Vol 47(1), 112-122.

This study explores the role of cortisol and early life experiences in the regulation of maternal behavior and mood in teen and adult mothers. Primiparous mothers (n = 119) (teen mothers < 19 years, n = 42), young mothers (19-25 years, n = 34), and mature mothers, (>25 years, n = 43) were assessed for their maternal behavior, mood, and hormonal profile at approximately 6 weeks postpartum. Outcome measures were analyzed as a function of age and early life experience. Results showed an interaction between age and type of maternal behavior, where teen mothers engaged in more instrumental (e.g. changing diapers, adjusting clothes) less affectionate (e.g., stroking, kissing, patting) behavior, and mature mothers engaged in more affectionate and less instrumental behavior. When groups were reassessed based on early life experience (consistency of care during the first 12 years of life: consistent care; having at least one consistent caregiver, inconsistent care; having multiple and changing caregivers), an interaction was also found between consistency of care and type of behavior shown, where mothers who received inconsistent care engaged in more instrumental and less affectionate behavior. Compared to mature mothers, teen mothers who were breast feeding also had higher salivary cortisol levels, and high cortisol in teen mothers related to decreased fatigue and increased energy. These results suggest that early life experiences are linked to mothering behavior and are consistent with the emerging human and animal literature on intergenerational effects of mothering style.

Minkkinen, Molly Harney. 2005). Does the concentration of cortisol in mother's breast milk have a relationship with the behavior of the infant. Dissertation Abstracts International Section A: Humanities and Social Sciences, Vol 65(8-A), 2892.

The purpose of this study was to determine whether the concentration of cortisol in maternal breast milk had an impact on infant behavior beyond the influence of the mother's stress related behaviors. Nineteen mother infant breast feeding pairs were recruited to participate in this study from two Midwestern states. Maternal stress levels, cortisol production in breast milk, maternal socio-economic levels, and infant behavior were assessed. Maternal stress was assessed using the State-Trait Anxiety Inventory, cortisol in breast milk was analyzed using and ELIZA (enzyme immunoassay) instrument, maternal SES was assessed with a tool designed by the researcher, and infant behavior was assessed using the Rothbart Infant Behavior Questionnaire-Revised. Data were analyzed using Spearman Correlation Coefficients and multiple linear regression. The results show that the women who participated in this study had middle to high family income levels and most had a college education. The mothers also scored low on the State and Trait Anxiety test compared to the normative sample which suggests that the women who participated in this study exhibited lower than average levels of acute and chronic stress. The infants who participated in this study also tested differently than the normative sample. The infants were generally happier than the normative sample. No comparison samples were available in the literature on levels of cortisol in maternal breast milk. Spearman correlation analysis showed a significant relationship between state and trait anxiety as well as a suggestion of a relationship between trait anxiety scores and negative affectivity scores as well as between positive affectivity and negative affectivity Rothbart scores. Linear regression analysis results indicated that there were no significant relationships between the dependent and independent variables, although the independent variables did account for 16-26% of the variance in the Rothbart scores.

Hart, Sybil; Boylan, L. Mallory; Border, Barbara; Carroll, Sebrina R.; McGunegle, Daniel; Lampe, Richard M. Breast milk levels of cortisol and Secretory Immunoglobulin A (SIgA) differ with maternal mood and infant neuro-behavioral functioning. Infant Behavior & Development, Vol 27(1), 101-106.

Cortisol's concentration in breast milk of mothers (N = 32) was found positively correlated with maternal self-reported hostility, and with neonatal performance on the NBAS Autonomic Stability cluster. Greater Secretory Immunoglobulin A (SIgA) in milk was linked with mothers' heightened depression, and with neonates' superior NBAS Orientation scores.

Ingram, Jennifer C.; Greenwood, R. J.; Woolridge, M. W. (2003). Hormonal predictors of postnatal depression at 6 months in breastfeeding women. Journal of Reproductive and Infant Psychology, Vol 21(1), 61-68.

Postnatal depression occurs in 10-15% of postpartum women. Studies have shown associations with endogenous hormone levels (oestrogen, progesterone, cortisol and thyroxin) and with autoimmune thyroid dysfunction. Breastfeeding has not been shown to increase the risk of developing postpartum depression. A prospective study involving 54 breastfeeding mothers of mixed parity and similar socio-economic status and education used bivariate analysis to look for associations between hormone levels and postnatal depression. Total oestradiol, total progesterone, prolactin and thyrotropin (TSH) levels were determined at four time points (ante- and postnatally) from finger prick blood spots by fluoro-immunoassay. Edinburgh Postnatal Depression Scale and life event check lists were completed at 6 months postpartum. Ten women were screened positive for sub-clinical depression (score ≥ 10). Bivariate analysis showed that antenatal prolactin and postpartum progesterone levels were significantly associated with postnatal depression at 6 months (p=0.03). Only the result for progesterone persisted in a multiple logistic regression, which controlled for life events. Women with lower progesterone levels in the immediate postnatal period were more likely to be depressed at 6 months.

Lankarani-Fard, Azadeh; Kritz-Silverstein, Donna; Barrett-Connor, Elizabeth; Goodman-Gruen, Deborah. (2001). Cumulative duration of breast- feeding influences cortisol levels in postmenopausal women. Journal of Women's Health & Gender-Based Medicine, Vol 10(7), 681-687.

Cortisol levels dramatically increase during pregnancy, peak at birth, and subsequently decline. However, all previous studies examined women during pregnancy and early postpartum. None examined the long-term association of parity and lactation with cortisol levels. This study examined the relation of reproductive history to cortisol levels in postmenopausal women. Ss were 749 women, aged 50–89 yrs, who were not using estrogen in 1984–1987 when morning cortisol was measured. Parity was not significantly associated with cortisol. However, women who breast-fed for >12 mo had significantly higher cortisol levels than women who breast-fed for shorter durations or not at all. This association was stronger among women with three or more births. Duration of breast-feeding is a determinant of cortisol levels in postmenopausal women. Because both increased cortisol and increased duration of breast-feeding may play protective roles in certain autoimmune diseases, such as rheumatoid arthritis, the authors suggest that the beneficial effect of lactation on the course of these diseases may be mediated by cortisol.

Redwine, Laura S.; Altemus, Margaret; Leong, Yeung-Mei; Carter, C. Sue. (2001). Lymphocyte responses to stress in postpartum women: Relationship to vagal tone. Psychoneuroendocrinology, Vol 26(3), 241-251.

Evaluated differential effects of breastfeeding, bottlefeeding and non-postpartum status on lymphocyte responses to stressful tasks (public speaking and mental arithmetic). 36 women (aged 20–40 yrs) were tested. To measure cellular immune responses, lymphocyte proliferation to plant lectins, poke weed mitogen (PWM) and phytohemagglutinin (PHA) were used. The autonomic measures, heart rate, vagal tone, blood pressure and the hormones of the HPA axis, ACTH and cortisol, were measured and their possible roles in mediating lymphocyte proliferation responses were examined. Recently parturient women who were breastfeeding or bottlefeeding had attenuated stress-induced change in lymphocyte responses to PWM compared with non-postpartum women, tested in the follicular phase of their cycle. Also, lymphocyte responses to PHA were higher in the breastfeeding group compared with non-postpartum controls. Regression analyses revealed that an index of cardiac vagal tone, but not other autonomic or endocrine measures, was positively predictive of lymphocyte proliferation to PWM. To summarize, these findings suggest that lactation and parturition can influence lymphocyte proliferation and that activity in the vagal system may influence lymphocyte responses to stress.

Marshall, Wilma Margaret. (1995). Psychophysiological aspects of lactation. Dissertation Abstracts International: Section B: The Sciences and Engineering, Vol 55(7-B), 3055.

The primary objective of this study was to record peripheral and hormonal psychophysiological responses during breastfeeding in order to more accurately describe the physiological changes which occur. More specifically, this study investigated whether any consistency could be observed among a group of six successfully breastfeeding women in terms of their finger temperature (FT) and skin conductance response (SCR), and in terms of their oxytocin (OXT), luteinizing hormone (LH) and cortisol responses during a feeding. This study also constituted a preliminary methodological and measurement investigation, designed to develop procedures permitting the rapid simultaneous recording and subsequent analysis of peripheral and hormonal measures during a feeding. Data were recorded for five minutes prior to the initiation of a feeding, and at one-minute intervals for the following ten minutes. Relative to the initiation of feeding, significant increases (p <05) in FT, relative to initiation, were recorded at minutes six through thirteen. When centered to the onset of Finger Temperature elevation, specific patterns of change were observed. SCR increases occurred prior to, and fell shortly after, a significant increase in finger temperature which remained elevated for the remainder of the recording period. By one minute after the onset of temperature rise there were increases in OXT, LH, and cortisol. OXT remained elevated relative to baseline with a clear second peak by minute eight. LH fell to baseline by minute three, and remained at or below baseline for the remainder of the sampling interval. Cortisol showed an intermittent pattern with an abrupt drop to baseline by minute eight. The broad context of this research has been to suggest a more integrative perspective for psychophysiology research in general, and for women's health issues in particular. The results suggest the need for more exploratory research and a series of focussed investigations considering female p.

Taylor, Alyx; Littlewood, Julia; Adams, Diana; Doré, Caroline; et al. (1994). Serum cortisol levels are related to moods of elation and dysphoria in new mothers. Psychiatry Research , Vol 54(3), 241-247.

Measured serum cortisol levels in 163 women on the 3rd day after childbirth and related these levels to their scores on self-rating scales of low and high moods. Significantly elevated levels of cortisol were found to be associated with depressed moods, and significantly lower levels characterized women who exhibited mild hypomania. Low levels of cortisol were independently associated with epidural anesthesia, while elevated levels were related to assisted delivery. There was no significant association with breast or bottle feeding. Changes in serum cortisol were thus found to parallel the mild bidirectional changes in affect that frequently follow childbirth.

Magnano, Catherine L.; Diamond, Edward J.; Gardner, Judith M. (1989). Use of salivary cortisol measurements in young infants: A note of caution. Child Development, Vol 60(5), 1099-1101.

Measured cortisol concentrations in 3 common infant milk formulas and in breast milk before and after defatting and extraction using a commercial radioimmunoassay kit. Cortisol concentrations obtained prior to defatting and extraction were equal to or higher than levels reported for salivary cortisol levels reported in newborn infants. Cortisol concentrations obtained after the defatting and extraction were lower, indicating that values obtained prior to defatting and extraction were due to cross-reacting substances as well as cortisol. As saliva samples are not routinely defatted or extracted prior to being assayed, high cortisol levels and interfering substances in formula and breast milk may contaminate salivary cortisol measurements in young infants. Findings suggest that appropriate controls should be taken when making salivary cortisol measurements in young infants to help ensure accurate results.