Breast-feeding and maternal cardiovascular function

The relationship between maternal smartphone use, physiological responses, and gaze patterns during breastfeeding and face-to-face interactions with infant

Smartphone use during parent-child interactions is highly prevalent, however, there is a lack of scientific knowledge on how smartphone use during breastfeeding or face-to-face interactions may modulate mothers’ attentive responsiveness towards the infant as well as maternal physiological arousal. In the present study, we provide the first evidence for the influence of the smartphone on maternal physiological responses and her attention towards the infant during breastfeeding and face-to-face interactions. Twenty breastfeeding mothers and their infants participated in this lab study during which electrodermal activity, cardiograph impedance, and gaze patterns were monitored in breastfeeding and face-to-face interactions with three conditions manipulating the level of maternal smartphone involvement. We report that mothers’ gaze toward their infants decreased when breastfeeding while using the smartphone compared to face-to-face interaction. Further, we show that greater maternal electrodermal activity and cardiac output were related to longer maternal gaze fixation toward the smartphone during breastfeeding. Finally, results indicate that mothers’ smartphone addiction levels were negatively correlated with electrodermal activity during breastfeeding. This study provides an initial basis for much required further research that will explore the influence of smartphone use on maternal biobehavioral responses in this digital age and the consequences for infant cognitive, emotional, and social development.

Cardiac output and peripheral vascular resistance during normotensive and hypertensive pregnancy - a systematic review and meta-analysis

BACKGROUND

In-depth insight into haemodynamic changes during normotensive pregnancy may help identify women at risk for gestational hypertensive complications.

OBJECTIVES

To determine the magnitude of changes in cardiac output and its determinants stroke volume and heart rate, and total peripheral vascular resistance during singleton normotensive and hypertensive pregnancies.

SEARCH STRATEGY

PubMed (NCBI) and Embase (Ovid) databases were searched from their inception up to November 2019.

SELECTION CRITERIA

Studies reporting original measurements of haemodynamic parameters during pregnancy together with a non-pregnant reference measurement. Studies including women using antihypertensive medication were excluded.

DATA COLLECTION AND ANALYSIS

Pooled mean differences between pregnant and non-pregnant women, and absolute values of haemodynamic parameters were calculated for predefined gestational intervals using a random-effects model in normotensive and hypertensive pregnancy. Meta-regression analysis was used to analyse group differences in adjustments and absolute values during pregnancy.

MAIN RESULTS

In normotensive pregnancies, cardiac output increased from the first weeks on, reaching its highest level early in the third trimester (mean difference, 1.41 l·min¹ ; 95% CI 1.18-1.63 l·min^-1 ). In parallel, vascular resistance decreased progressively until its nadir in the early third trimester (mean difference, -331 dyn·sec^-1 ·cm^-5 ; 95% CI -384 to -277 dyn·sec^-1 ·cm^-5 ) and then increased slightly at term. In hypertensive pregnancies, the initial cardiac output increase was higher and vascular resistance did not change throughout gestation compared with reference values.

CONCLUSIONS

Hemodynamic changes in women who eventually develop hypertensive complications are substantially different. Serial monitoring and plotting against developed normograms can identify women at risk and may allow timely intervention.

TWEETABLE ABSTRACT

Monitoring haemodynamic changes in pregnancy helps identify women at risk for hypertensive complications.

Association Between Duration of Breastfeeding and Maternal Hypertension: A Systematic Review and Meta-Analysis

OBJECTIVES

Recently, an increasing number of studies have implied that breastfeeding has a protective effect on maternal hypertension, but it remains controversial. The aim of this study is to evaluate the effect of breastfeeding on maternal hypertension through meta-analysis.

MATERIALS AND METHODS

Eligible studies were searched and identified in various databases. Meta-analysis was conducted to assess the association between the duration of breastfeeding and maternal hypertension.

RESULTS

Seven eligible studies that contained 444,759 participants were included in our study. Meta-analysis of these seven studies showed a significant protective effect of breastfeeding on maternal hypertension. Specifically, pooled odds ratios (ORs) of hypertension for >0-6, >6-12, and >12 months of breastfeeding were 0.92 (95% confidence interval [CI]: 0.88-0.96, I² = 67.5%), 0.89 (95% CI: 0.86-0.92, I² = 0), and 0.88 (95% CI: 0.84-0.93, I² = 43.9%), respectively, compared with nonbreastfeeding mothers, and the pooled OR of hypertension was 0.93 (95% CI: 0.91-0.95, I² = 40.8%) for women who breastfed compared with women who had not. Furthermore, the pooled hazard ratio of hypertension was 1.34 (95% CI: 1.17-1.52, I² = 58.7%) for women who did not breastfeed compared with women who breastfed for more than 12 months for their first child.

CONCLUSION

Different durations of breastfeeding have different protective effects against the development of maternal hypertension, and breastfeeding for >12 months has a better effect than <12 months.

Echocardiographic and electrocardiographic parameters during the normal postpartum period in toy breeds of dogs

The aim of this study was to evaluate echocardiographic and electrocardiographic parameters during the normal canine postpartum period. Twenty clinically healthy pregnant bitches of toy breeds (11 Miniature poodles, five Yorkshire terriers, two Maltese terriers and two Bichons Frises) were evaluated on days -3, 3, 10, 17, 24, 38, 52 and 80 relative to parturition (day 0). During the first postpartum week, the width of the interventricular septum in systole, the shortening fraction and the left atrium size decreased, while the left ventricle internal diameter in systole and end systolic stress increased. There were progressive decreases in the velocity of circumferential fibre shortening, stroke volume, cardiac output, and mitral E and A wave values. Systolic blood pressure increased markedly during the first postpartum week to gradually increase thereafter. Heart rate and corrected QT interval progressively decreased, while P wave amplitude increased. QRS complex amplitude decreased in the second week after parturition and then increased during the following weeks. In conclusion, there were changes in systolic function and some structural adaptive changes in the bitch during the first 80days postpartum. In addition, maternal heart rate and corrected QT interval decreased, while P wave and QRS amplitudes increased.

Cumulative Lactation and Onset of Hypertension in African-American Women

Hypertension affects nearly 1 of 3 women and contributes to cardiovascular disease, the leading cause of death in the United States. Breastfeeding leads to metabolic changes that could reduce risks of hypertension. Hypertension disproportionately affects black women, but rates of breastfeeding among black women lag behind those in the general population. In the Black Women's Health Study (n = 59,001), we conducted a nested case-control analysis using unconditional logistic regression to estimate the association between breastfeeding and incident hypertension at ages 40-65 years using data collected from 1995 to 2011. Controls were frequency-matched 2:1 to 12,513 hypertensive women by age and questionnaire cycle. Overall, there was little evidence of association between ever breastfeeding and incident hypertension (odds ratio = 0.97, 95% confidence interval: 0.92, 1.02). However, age modified the relationship (P = 0.02): Breastfeeding was associated with reduced risk of hypertension at ages 40-49 years (odds ratio = 0.92, 95% confidence interval: 0.85, 0.99) but not at older ages. In addition, risk of hypertension at ages 40-49 years decreased with increasing duration of breastfeeding (P for trend = 0.08). Our results suggest that long-duration breastfeeding may reduce the risk of incident hypertension in middle age. Addressing breastfeeding as a potential preventative health behavior is particularly compelling because it is required for only a discrete period of time.

Effect of Lactation on myocardial vulnerability to ischemic insult in rats

Background

Cardiovascular diseases are the leading cause of mortality and long-term disability worldwide. Various studies have suggested a protective effect of lactation in reducing the risk of cardiovascular diseases.

Objective

This study was designed to assess the effects of pregnancy and lactation on the vulnerability of the myocardium to an ischemic insult.

Methods

Eighteen female rats were randomly divided into three groups: ischemia-reperfusion (IR), in which the hearts of virgin rats underwent IR (n = 6); lactating, in which the rats nursed their pups for 3 weeks and the maternal hearts were then submitted to IR (n = 6); and non-lactating, in which the pups were separated after birth and the maternal hearts were submitted to IR (n = 6). Outcome measures included heart rate (HR), left ventricular developed pressure (LVDP), rate pressure product (RPP), ratio of the infarct size to the area at risk (IS/AAR %), and ventricular arrhythmias - premature ventricular contraction (PVC) and ventricular tachycardia (VT).

Results

The IS/AAR was markedly decreased in the lactating group when compared with the non-lactating group (13.2 ± 2.5 versus 39.7 ± 3.5, p < 0.001) and the IR group (13.2 ± 2.5 versus 34.0 ± 4.7, p < 0.05). The evaluation of IR-induced ventricular arrhythmias indicated that the number of compound PVCs during ischemia, and the number and duration of VTs during ischemia and in the first 5 minutes of reperfusion in the non-lactating group were significantly (p < 0.05) higher than those in the lactating and IR groups.

Conclusion

Lactation induced early-onset cardioprotective effects, while rats that were not allowed to nurse their pups were more susceptible to myocardial IR injury.

Measuring stress responses in female Geoffroy's spider monkeys: Validation and the influence of reproductive state

Fecal glucocorticoid metabolites are increasingly used to investigate physiological stress. However, it is crucial for researchers to simultaneously investigate the effects of reproductive state because estradiol and placental hormones can affect circulating glucocorticoid concentrations. Reports on the relationships between glucocorticoids and reproductive state are inconsistent among females. Unlike several primate species that have heightened glucocorticoid activity during lactation, humans experience reduced glucocorticoid activity during lactation. Rather than a taxonomic difference, we hypothesize that this is a result of different environmental stressors, particularly the threat of infanticide. Here, we expand the number of wild primate species tested by validating a glucocorticoid assay for female Geoffroy's spider monkeys. We investigate the effects of reproductive state on their glucocorticoid concentrations. Utilizing a routine veterinary exam on a captive population, we determined that fecal glucocorticoid metabolites increase in response to a stressor (anesthesia), and this rise is detected approximately 24 hr later. Additionally, we found that extracted hormone patterns in a wild population reflected basic reproductive biology-estradiol concentrations were higher in cycling than lactating females, and in lactating females with older offspring who were presumably resuming their cycle. However, we found that estradiol and glucocorticoid concentrations were significantly correlated in lactating but not cycling females. Similarly, we found that reproductive state and estradiol concentration, but not stage of lactation, predicted glucocorticoid concentrations. Unlike patterns in several other primate species that face a relatively strong threat of infanticide, lactating spider monkeys experience reduced glucocorticoid activity, possibly due to attenuating effects of oxytocin and lower male-initiated aggression than directed at cycling females. More broadly, we conclude that future studies using fecal glucocorticoid metabolites to index stress should consider that reproductive state might confound glucocorticoid measurements. Am. J. Primatol. 77:925-935, 2015. © 2015 Wiley Periodicals, Inc.

Lactation Duration and Midlife Atherosclerosis

OBJECTIVE

To evaluate lactation duration in relation to subsequent atherosclerosis in women during midlife.

METHODS

The Coronary Artery Risk Development in Young Adults study is a multicenter prospective cohort that enrolled 2,787 women in 1985-1986 (ages 18-30 years, 52% black, 48% white), of whom 2,014 (72%) attended the 20-year follow-up examination in 2005-2006. We selected 846 women (46% black) without heart disease or diabetes at baseline who delivered one or more times after the baseline evaluation, had cardiometabolic risk factors measured at baseline, and had maximum common carotid intima-media thickness (mm) measured at the 20-year follow-up examination in 2005-2006. Lactation duration was summed across all postbaseline births for each woman and (n, women) categorized as: 0 to less than 1 month (n=262), 1 to less than 6 months (n=210), 6 to less than 10 months (n=169), and 10 months or greater (n=205). Multiple linear regression models estimated mean common carotid intima-media thickness (95% confidence interval) and mean differences among lactation duration groups compared with the 0 to less than 1-month group adjusted for prepregnancy obesity, cardiometabolic status, parity, and other risk factors.

RESULTS

Lactation duration had a graded inverse association with common carotid intima-media thickness; mean differences between 10 months or greater compared with 0 to less than 1 month ranged from -0.062 mm for unadjusted models (P trend <.001) to -0.029 mm for models fully adjusted for prepregnancy body mass index (BMI) and cardiometabolic risk factors, parity, smoking, and sociodemographics (P trend=.010). Stepwise addition of potential mediators (BMI, systolic blood pressure at the 20-year follow-up examination) modestly attenuated the lactation and common carotid intima-media thickness association to -0.027 and -0.023 mm (P trend=.019 and .054).

CONCLUSION

Shorter lactation duration is associated with subclinical atherosclerosis independent of prepregnancy cardiometabolic risk factors and traditional risk factors. The magnitude of differences in carotid artery intima-media thickness may represent greater vascular aging. Lactation may have long-term benefits that lower cardiovascular disease risk in women.

LEVEL OF EVIDENCE

II.

Oxytocin differently regulates pressor responses to stress in WKY and SHR rats: the role of central oxytocin and V1a receptors

The role of central oxytocin in the regulation of cardiovascular parameters under resting conditions and during acute stress was investigated in male normotensive Wistar-Kyoto (WKY; n = 40) and spontaneously hypertensive rats (SHR; n = 28). In Experiment 1, mean arterial blood pressure (MABP) and heart rate (HR) were recorded in WKY and SHR rats at rest and after an air-jet stressor during intracerebroventricular (ICV) infusions of vehicle, oxytocin or oxytocin receptor (OTR) antagonist. In Experiment 2, the effects of vehicle, oxytocin and OTR antagonist were determined in WKY rats after prior administration of a V1a vasopressin receptor (V1aR) antagonist. Resting MABP and HR were not affected by any of the ICV infusions either in WKY or in SHR rats. In control experiments (vehicle), the pressor response to stress was significantly higher in SHR. Oxytocin enhanced the pressor response to stress in the WKY rats but reduced it in SHR. During V1aR blockade, oxytocin infusion entirely abolished the pressor response to stress in WKY rats. Combined blockade of V1aR and OTR elicited a significantly greater MABP response to stress than infusion of V1a antagonist and vehicle. This study reveals significant differences in the regulation of blood pressure in WKY and SHR rats during alarming stress. Specifically, the augmentation of the pressor response to stress by exogenous oxytocin in WKY rats is caused by its interaction with V1aR, and endogenous oxytocin regulates the magnitude of the pressor response to stress in WKY rats by simultaneous interaction with OTR and V1aR.

Duration of lactation and incidence of myocardial infarction in middle to late adulthood

OBJECTIVE

We assessed the relation between duration of lactation and maternal incident myocardial infarction.

STUDY DESIGN

This was a prospective cohort study of 89,326 parous women in the Nurses' Health Study.

RESULTS

During 1,350,965 person-years of follow-up, 2540 cases of coronary heart disease were diagnosed. Compared with parous women who had never breastfed, women who had breastfed for a lifetime total of 2 years or longer had 37% lower risk of coronary heart disease (95% confidence interval, 23-49%; P for trend < .001), adjusting for age, parity, and stillbirth history. With additional adjustment for early-adult adiposity, parental history, and lifestyle factors, women who had breastfed for a lifetime total of 2 years or longer had a 23% lower risk of coronary heart disease (95% confidence interval, 6-38%; P for trend = .02) than women who had never breastfed.

CONCLUSION

In a large, prospective cohort, long duration of lactation was associated with a reduced risk of coronary heart disease.

Short- and long-term decrease of blood pressure in women during breastfeeding

BACKGROUND AND AIMS

The benefits of breastfeeding for infants are well known. Recently data have started to emerge showing that breastfeeding may also induce positive effects in the mother. This study aimed to investigate the pattern of maternal blood pressure before, during, and after a breastfeed 2 days postpartum. Additionally, blood pressure during the following 25-week breastfeeding period was investigated.

METHODS

Sixty-six primiparae with normal deliveries were consecutively recruited. Blood pressure was measured at -5, 10, 30, and 60 minutes in connection with a morning breastfeed. Thirty-three women continued to measure blood pressure before and after breastfeeding for 25 weeks.

RESULTS

Blood pressure fell significantly in response to breastfeeding 2 days after birth. The fall in systolic and diastolic blood pressure amounted to 8.8 (SD = 11.00) and 7.7 (SD = 9.3) mm Hg, respectively. During the 25-week follow-up period a significant fall of basal blood pressure (systolic, df = 3, F = 7.843, p < 0.001; diastolic, df = 3, F = 5.453, p = 0.002) was observed. The total fall in systolic and diastolic blood pressure amounted to a mean of 15 (SD = 10.4) mm Hg and 10 (SD = 9.7) mm Hg, respectively. In addition, blood pressure fell significantly in response to individual breastfeeding sessions during the entire observation period.

CONCLUSIONS

In conclusion, both systolic and diastolic blood pressures fall during a breastfeeding session, and pre-breastfeeding blood pressure decreases during at least the first 6 months of a breastfeeding period in a homelike environment. This study lends further support to the health-promoting effects of breastfeeding.

Effects of an acute stressor on blood pressure and heart rate in rats pretreated with intracerebroventricular oxytocin injections

Oxytocin induces a long-lasting reduction of blood pressure in rats. The aim of the present study was to investigate the effects of an acute stressor on blood pressure and heart rate in rats previously exposed to repeated administration of intracerebroventricular (ICV) oxytocin. For this purpose oxytocin (0.3 microg, ICV) was administered to male rats once a day during 5 days. Blood pressure and heart rate were measured before and after treatment. In addition, blood pressure and heart rate were measured during 30 min after exposure to 10s of noise from an alarm clock. The oxytocin treatment reduced blood pressure significantly (systolic: 108+/-4.6 vs. 121+/-1.8, p<0.01, diastolic: 96+/-5.1 vs. 108+/-3.0, p<0.01), whereas heart rate remained unchanged. In contrast, systolic and diastolic blood pressure increased significantly after the exposure to the ringing alarm clock in the oxytocin-treated rats (p<0.05), and became equal to the blood pressure in controls. In addition, heart rate increased and stayed significantly higher in the oxytocin-treated rats compared to the controls during the 30 min observation period (ANOVA p<0.01). Twenty-four hours later, blood pressure was again significantly lower in the oxytocin-treated rats compared to controls (p<0.01). In conclusion, oxytocin decreased blood pressure without changing pulse rate. However, when the oxytocin-treated rats were subjected to the unexpected noise from a ringing alarm clock blood pressure and heart rate increased significantly. No such effect was observed in the control group. Thus repeated oxytocin treatment can, in spite of decreasing blood pressure during basal conditions, increase cardiovascular reactivity to some types of stressors.

Multiparity reveals the blunting effect of breastfeeding on physiological reactivity to psychological stress

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.

Activation of the hypothalamo-pituitary-adrenal axis by isolation and restraint stress during lactation in ewes: effect of the presence of the lamb and suckling

We investigated the effect of the presence and absence of lambs and suckling by lambs to attenuate activation of the hypothalamo-pituitary-adrenal (HPA) axis to isolation and restraint stress in lactating sheep. In experiment 1, blood samples were collected every 10 min from nonlactating (n = 5) and lactating (n = 5) ewes for 4 h before and during stress. In experiment 2, ewes (n = 6) were allocated to 1) nonlactating, 2) lactating with lambs absent, 3) lactating with lambs present but unable to suckle, and 4) lactating with lambs present and able to suckle. Blood samples were collected over 8 h with no stress (control day) and for 4 h before and 4 h during stress (stress day). In experiment 1, the mean (+/-SEM) cortisol concentrations increased significantly (P < 0.05) in nonlactating ewes during stress but did not change in lactating ewes. In experiment 2, cortisol did not vary on the control day or pretreatment of the stress day but increased (P < 0.05) during stress in all groups except lactating ewes with lambs present and able to suckle. The greatest cortisol response occurred in nonlactating ewes followed by lactating ewes with lambs absent and lactating ewes with lambs present but unable to suckle. During stress, the ACTH concentrations increased (P < 0.05) in nonlactating ewes and lactating ewes with lambs absent but not in lactating ewes with lambs present. We conclude that the activity of the HPA axis during isolation and restraint is reduced in lactating ewes and that the presence of lambs increases this level of attenuation.

Does long-term lactation protect premenopausal women against hypertension risk? A Korean women's cohort study

BACKGROUND

Little is known about the long-term effect of lactation on maternal cardiovascular health except for a few animal or human experimental studies. The objective of this study was to examine the effects of lactation on the incidence of hypertension in premenopausal women.

METHODS

The data were derived from a cohort study with 6 years follow-up (1995-2000). The cohort was composed of 177,749 Korean premenopausal women, aged 20-59, who had medical evaluations in 1992 and 1994. During the follow-up, blood pressure was measured as part of the 1996, 1998, and 2000 periodic examinations.

RESULTS

In multivariate Cox proportional hazard models, lactation decreased the risk of hypertension (risk ratio, 0.92; 95% confidence interval, 0.90-0.96). Compared with women who with no history of lactation, 1-6 months of lactation decreased the risk of hypertension (RR, 0.90; 95% CI, 0.87-0.93), as did 7-12 months (RR, 0.92; 95% CI, 0.87-0.98) or 13-18 months (RR, 0.93; 95% CI, 0.86-0.99). In particular, the coexistence of obesity and no lactation increased the risk of hypertension (P for interaction = 0.028).

CONCLUSION

This finding suggests that lactation may be a protective factor against hypertension among premenopausal women.

Breast feeding, bottle feeding, and maternal autonomic responses to stress

OBJECTIVE

The aim of this study was to examine the effects of breast feeding on autonomic nervous system (ANS) response to stressors.

METHODS

Sympathetic and parasympathetic activities were examined before, during, and after standard laboratory stressors in women who were either exclusively breast feeding (n=14) or nonexclusively breast feeding (n=14), and in non-postpartum controls (n=15).

RESULTS

Mothers who breast fed exclusively showed greater levels of parasympathetic cardiac modulation and slower heart rate (HR) throughout the session and less HR increase and preejection period (PEP) shortening to mental arithmetic (MA) than did nonexclusive breast feeders and controls. Nonexclusive breast-feeders showed greater electrodermal reactivity to, and greater differences in skin conductance response (SCR) frequency between baseline and recovery from cold pressor (CP) than did either exclusive breast-feeders or controls. Sympathetic activity was negatively related to the number of breast feedings and positively related to bottle feedings.

CONCLUSION

Breast feeding shifts maternal ANS balance toward relatively greater parasympathetic and lesser sympathetic activity; the opposite occurs with bottle feeding. The frequency of feeding also is a critical factor in determining breast feeding effects on maternal ANS function.

Maternal psychophysiological change during the second half of gestation

This study investigated the trajectory of physiological and psychological functioning during the second half of pregnancy and compared responsiveness to a laboratory stressor between pregnant and non-pregnant women. Monitoring of 137 pregnant women at 20, 24, 28, 32, 36, and 38 weeks of pregnancy included measures of heart period (HP), heart period variability (HPV), skin conductance (SCL), respiratory period (RP), respiratory sinus arrhythmia (RSA), and self-report of mood disturbance. HP and RSA declined during this period; SCL and mood disturbance increased. Parity was a significant moderator. HP and SCL responsiveness to the Stroop color-word task was assessed twice in pregnant participants and compared to a sample of 27 non-pregnant women. Physiologic responsiveness was reduced in pregnant women. Pregnant women perceived the Stroop to be more difficult, but performance was unaffected. Despite buffered responsivity to stressful stimuli during pregnancy, advancing gestation is associated with escalating sympathetic tone and declining parasympathetic tone.

Patterns of brain electrical activity in infants of depressed mothers who breastfeed and bottle feed: the mediating role of infant temperament

Successful breastfeeding involves a dyadic interaction between a mother and her infant. The present study was designed to examine the association between breastfeeding and temperament in infants of depressed mothers. Seventy-eight mothers, 31 who were depressed, and their infants participated. Depressed mothers who had stable breastfeeding patterns were less likely to have infants with highly reactive temperaments. Multivariate analyses of variances (MANOVAs) showed that infants of depressed mothers who breastfed did not show the frontal asymmetry patterns, i.e., left frontal hypoactivity, previously reported. Moreover, breastfeeding stability, even in depressed mothers, was related to more positive dyadic interactions. Finally, a model was supported, in which the effects of maternal depression on infant feeding are mediated by infant frontal EEG asymmetry and infant temperament. These findings could provide a foundation for developing intervention techniques, employing breastfeeding promotion and support, directed toward attenuating the affective and physiological dysregulation already noted in infants of depressed mothers.

Breastfeeding and Maternal Stress Response and Health

This article reviews findings on the maternal stress and health effects of lactation. Several significant associations have emerged. Compared with not breastfeeding, breastfeeding is associated with increased parasympathetic nervous system modulation, greater vascular stress response, lower perceived stress levels, and fewer depressive symptoms. Breastfeeding exclusively is associated with an attenuated initial sympathetic cardiac nervous system response to some laboratory stressors. Bottle-feeding is associated with increased sympathetic and decreased parasympathetic cardiac control. The act of breastfeeding is associated with decreased neuroendocrine response to stressors and decreased negative mood. Finally, breastfeeding is associated with enhanced physical and mental health compared with non-breastfeeding.