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

The Importance of Personal and Familial Factors on Breastfeeding Intention and Practices, and Postpartum Distress during the Pandemic: A Longitudinal Observational Study

BACKGROUND

The COVID-19 pandemic has significantly impacted pregnant and breastfeeding women. Both low- and high-risk groups adopted preventive approaches such as mask-wearing and handwashing to slow down and prevent viral transmission during critical periods that may affect mother-child interactions.

METHODS

A longitudinal observational study was conducted with primiparous women recruited using convenience sampling from the postpartum care ward of Afzalipour Teaching Hospital in Kerman from August 1, 2020 to March 30, 2021. The research questionnaires included demographic information, preventive behaviors, breastfeeding intention and practices, postpartum distress, and Edinburgh Postpartum Depression Scale. All the questionnaires were self-reported online in three stages: before discharge from the postpartum ward, the first month after delivery, and the third month after delivery.

RESULTS

A Total of 160 primiparous women were included. The results showed significant changes in preventive behaviors and postpartum distress levels during the study. Breastfeeding intention and practices were negatively affected by postpartum distress (P = 0.034), unwanted pregnancies (P = 0.009), and cesarean delivery (P < 0.001). Postpartum distress was directly affected by the presence of depression (P < 0.001). Preventive behaviors at discharge were significantly associated with postpartum distress three months after delivery (P = 0.013). The study also found an association between women's and partner's education, unwanted pregnancy, and cesarean delivery that determined postpartum distress.

CONCLUSIONS

Pandemic restrictions did not affect breastfeeding intentions or practices, possibly due to sufficient social and family support during the pandemic. However, robust guidelines are required to increase enable women's access to specializede care to cope with future pandemics, particularly during the first few weeks after childbirth.

Association between breastfeeding cessation among under six-month-old infants and postpartum depressive symptoms in Nevada

BACKGROUND

Postpartum depression affects 13% of women after childbirth in the United States. Mothers who experience depression are less likely to breastfeed than those who do not experience depression. On the other hand, breastfeeding may have a positive effect on maternal mental health.

RESEARCH AIM

We aimed to analyze whether breastfeeding cessation is associated with postpartum depression symptoms among mothers of infants under six months old in Clark County, Nevada.

METHOD

A cross-sectional study was conducted in 2021 using a purposive sample of 305 mother-infant dyads. Postpartum depression symptoms were assessed using the Patient Health Questionnaire-2 (PHQ-2), and the breastfeeding cessation was determined through a 24-hour dietary recall. Descriptive, bivariate, and multivariate logistic regression analyses were conducted.

RESULTS

Most participants were between 25 and 34 years old (n = 183, 60.0%), multiparous (n = 167, 55.1%), and had a vaginal delivery (n = 204, 70.6%). High frequency of postpartum depressive symptoms was found among mothers who were young (18-24 years) (24.2%), without a partner (25.0%), had unplanned pregnancies (12.7%), and were primiparous (13.2%). Breastfeeding cessation was independently associated with postpartum depressive symptoms (AOR = 3.30, 95% CI: 1.16-9.32) after controlling for sociodemographic, environmental, and obstetric characteristics.

CONCLUSION

Breastfeeding cessation is strongly associated with postpartum depressive symptoms among mother-infant dyads in Nevada. Early identification of postpartum depressive symptoms and the promotion of breastfeeding can create a positive feedback loop to foster the well-being of mothers and infants.

Breastfeeding and Bonding: A Surprising Role of Breastfeeding Difficulties

Aims: To explore the role of breastfeeding difficulties in bonding. Background: Studies published to date yielded varying results regarding the relationship between breastfeeding and bonding. In qualitative studies, mothers often describe breastfeeding as a bonding experience and regard breastfeeding difficulties as challenging. Only one quantitative study explored the impact of breastfeeding difficulties on bonding. Methods: A cross-sectional method was used and a self-report questionnaire was administered to a convenience sample of mothers with infants aged 0-6 months. Results: We found that having problem-free breastfeeding versus breastfeeding associated with breastfeeding difficulties led to a difference in bonding quality. Experiencing any breastfeeding difficulties was associated with bonding impairment (p = 0.000, r = 0.174), especially in cases of breast engorgement (p = 0.016, r = 0.094), a nonlatching baby (p = 0.000, r = 0.179), perceived low milk supply (p = 0.004, r = 0.112), and fussing at the breast (p = 0.000, r = 0.215). We also found a difference in bonding impairment between exclusively breastfeeding and exclusively bottle-feeding mothers (p = 0.001), but only when taking into account breastfeeding difficulties. Conclusions: Breastfeeding is a complex interaction that can be associated with mother-infant bonding in various ways. We found that breastfeeding difficulties were linked to bonding impairment, whereas exclusive breastfeeding without the presence of breastfeeding difficulties was not. Strategies to help achieve exclusive breastfeeding and prevent and resolve breastfeeding difficulties may help mothers fulfill the bonding potential with their infant.

Maternal physiological calming responses to infant suckling at the breast

The mother-infant relation is key to infant physical, cognitive and social development. Mutual regulation and cooperation are required to maintain the dyadic system, but the biological foundation of these responses remains to be clarified. In this study, we report the maternal calming responses to infant suckling during breastfeeding. Using behavioral measures and a Holter electrocardiogram as a readout of the maternal autonomic nervous system, the maternal activities during resting, sitting with her infant on her lap, and breastfeeding were assessed. We found that during breastfeeding, mothers talked less and maternal heart rate was lower than during sitting with the infant without breastfeeding. Congruently, maternal heart rate variability measurements indicated a higher parasympathetic activity during breastfeeding. Time-locked analyses suggested that this maternal calming response was initiated by the tactile stimulation at the breast by the infant face or mouth latch, which preceded the perceived milk ejection. These findings suggest that somatosensory stimuli of breastfeeding activate parasympathetic activity in mothers. Just as how the infant Transport Response facilitates the carrying of infants, the maternal calming responses during breastfeeding may promote efficient milk intake by inhibiting spontaneous maternal activities.

Breastfeeding duration and vagal regulation of infants and mothers

BACKGROUND

Vagal regulation within the parasympathetic nervous system supports self-regulation and social engagement. Research has suggested that early feeding practices may influence mother-infant vagal functioning.

AIM

We aimed to examine the association between breastfeeding duration and mother-infant vagal regulation during an interaction. We hypothesized that breastfeeding duration would be positively associated with adaptive vagal regulation in infants and mothers.

METHOD

204 mother-infant dyads (infant mean age 6 months) completed the face-to-face still-face (FFSF) task. During the task, vagal regulation indexed by respiratory sinus arrhythmia (RSA, a component of heart rate variability) was calculated through continuously recorded electrocardiogram signals. Breastfeeding duration and demographic information were reported by mothers. Linear mixed models were adopted to estimate the associations between breastfeeding duration and repeated measures of RSA in infants and mothers throughout the FFSF.

RESULTS

Infants breastfed for a longer duration demonstrated lower RSA throughout the FFSF (B = -0.06, 95 % CI: -0.09 to -0.03), suggesting active physiological mobilization to engage in interaction and regulate distress. Mothers with longer breastfeeding duration displayed higher baseline RSA and higher overall RSA levels (higher vagal control) during the FFSF (B = 0.06, 95 % CI: 0.02 to 0.09), indicating a calmer and regulated state.

CONCLUSION

Longer breastfeeding duration was associated with more adaptive mother-infant vagal regulation during the interaction, indicating a positive dose-response association. This finding reveals breastfeeding practice as a factor contributing to infant effective vagal regulation and further supports WHO recommendation on exclusive breastfeeding for the first 6 months and continuing breastfeeding to 24 months and beyond.

The Association of Breastfeeding with a Reduced Risk of Postpartum Depression: A Systematic Review and Meta-Analysis

Background: Previous research has noted an association between breastfeeding and a reduced risk of postpartum depression (PPD). This article provides a systematic review and meta-analysis on the possible association of the type and degree of breastfeeding and PPD. Methods: A systematic literature search in English was conducted by using PubMed, Google Scholar, Scopus, Web of Science, and Cochrane Library Databases from their start dates until January 2021. Outcome estimates were pooled by odds ratios (ORs) or standardized mean differences. Result: Women who did not exclusively breastfeed had 89% higher odds of PPD (OR = 1.89, 95% confidence interval [CI]: 1.50-2.39). Included studies used different cutoff points for the diagnosis of PPD. Therefore, PPD in nonexclusive breastfeeding mothers was more in studies using the cutoff point 9/10 (OR 1.97, 95% CI 1.46-2.64) as symptoms of depression than those using the cutoff point 12 (OR 1.78, 95% CI 1.21-2.61). Some studies reported PPD based on means and the others reported it based on OR. Accordingly, nonexclusive breastfeeding mothers had higher odds of PPD in studies calculating the effect size based on means (OR 1.62, 95% CI 1.19-2.19) and OR (OR 2.36, 95% CI 1.65-3.39) than in other studies. Conclusion: This review showed that exclusive breastfeeding is associated with a reduced risk for PPD.

Associations of Infant Feeding with Body Composition and Cardiometabolic Health in Young Female University Students

Background:

We assessed the association of infant feeding with body composition and cardiometabolic health at 20 years in a setting where infant feeding is not associated with socioeconomic status.

Materials and methods:

Body size trajectory since birth, current body composition measured using whole-body dual-energy X-ray absorptiometry, and a broad range of cardiometabolic risk factors were compared cross-sectionally among young female university students who were ever breastfed (n = 158, 120 exclusively, and 38 mainly), mixed fed (n = 124), and formula fed (n = 15, 10 mainly, and 5 exclusively)

Results:

Compared with breastfed and mixed fed women, formula fed women had higher serum total and low-density lipoprotein (LDL) cholesterol although fat mass, fat distribution, fasting glucose, and insulin and high-density lipoprotein cholesterol did not differ. In addition, resting heart rates were higher in formula fed women compared with the other two groups of women although systolic and diastolic blood pressure did not differ. Further, formula fed women had higher adiponectin while serum leptin did not differ. There was no difference in birthweight, weight and height in childhood and adolescence, and glucose tolerance. On multivariate logistic regression analysis, formula feeding was associated with resting heart rates (odds ratio [OR]: 1.06, confidence interval [95% CI]; 1.01–1.12, p = 0.01) and adiponectin (OR: 1.3, 95% CI; 1.1–1.5, p < 0.001) independently of serum total and LDL cholesterol.

Conclusions:

Breastfeeding may be associated with favorable lipid profile and autonomic nervous function in young adults through mechanisms unrelated to adiposity, implicating potential long-term benefits of breastfeeding for cardiovascular health. Higher adiponectin in nonbreastfed women warrants further studies.

How stress can influence brain adaptations to motherhood

Research shows that a woman's brain and body undergo drastic changes to support her transition to parenthood during the perinatal period. The presence of this plasticity suggests that mothers' brains may be changed by their experiences. Exposure to severe stress may disrupt adaptive changes in the maternal brain and further impact the neural circuits of stress regulation and maternal motivation. Emerging literature of human mothers provides evidence that stressful experience, whether from the past or present environment, is associated with altered responses to infant cues in brain circuits that support maternal motivation, emotion regulation, and empathy. Interventions that reduce stress levels in mothers may reverse the negative impact of stress exposure on the maternal brain. Finally, outstanding questions regarding the timing, chronicity, types, and severity of stress exposure, as well as study design to identify the causal impact of stress, and the role of race/ethnicity are discussed.

Improvement of the breastfeeding self-efficacy and postpartum mental health after lactation consultations - Observational study

OBJECTIVE

Maternal self-efficacy in breastfeeding may be undermined by common mental health difficulties in the postpartum, leading to an early breastfeeding cessation. The relationship may also be the opposite: problems with effective breastfeeding and breastfeeding cessation may increase the postpartum mental health difficulties. The purpose of this study was the assessment of the effectiveness of lactation consultations in strengthening the breastfeeding self-efficacy and maternal postpartum mental health.

DESIGN AND PARTICIPANTS

160 Polish women (90 consultation participants and 70 controls) completed a structured interview, the General Health Questionnaire, and the Breastfeeding Self-Efficacy Scale twice: before lactation consultation and one month later.

SETTING

Research was conducted in the city of Gdańsk, Poland.

FINDINGS

Study revealed that women seeking lactation support exhibited greater mental health difficulties while their breastfeeding self-efficacy was similar to the control group. Initial breastfeeding self-efficacy was negatively correlated with the severity of the postpartum mental health problems. One month after lactation consultations, a significant increase in the breastfeeding self-efficacy and significantly reduced symptoms of mental health difficulties (somatic symptoms, functional disorders, and anxiety and insomnia) were observed among mothers.

KEY CONCLUSIONS

Women willing to benefit from the lactation consultations may exhibit symptoms of mental health difficulties that may be associated with difficulties in breastfeeding. Strengthening the breastfeeding confidence during lactation consultations, may reflect in the improvement of the woman's mental health.

IMPLICATIONS FOR PRACTICE

Midwives and lactation consultants can make a difference in the mental health promotion by offering breastfeeding interventions which address the emotional needs of a mother.

The effects of acute work stress and appraisal on psychobiological stress responses in a group office environment

BACKGROUND

The high prevalence of office stress and its detrimental health consequences are of concern to individuals, employers and society at large. Laboratory studies investigating office stress have mostly relied on data from participants that were tested individually on abstract tasks. In this study, we examined the effect of psychosocial office stress and work interruptions on the psychobiological stress response in a realistic but controlled group office environment. We also explored the role of cognitive stress appraisal as an underlying mechanism mediating the relationship between work stressors and the stress response.

METHODS AND MATERIALS

Ninety participants (44 female; mean age 23.11 ± 3.80) were randomly assigned to either a control condition or one of two experimental conditions in which they were exposed to psychosocial stress with or without prior work interruptions in a realistic multi-participant laboratory setting. To induce psychosocial stress, we adapted the Trier Social Stress Test for Groups to an office environment. Throughout the experiment, we continuously monitored heart rate and heart rate variability. Participants repeatedly reported on their current mood, calmness, wakefulness and perceived stress and gave saliva samples to assess changes in salivary cortisol and salivary alpha-amylase. Additionally, cognitive appraisal of the psychosocial stress test was evaluated.

RESULTS

Our analyses revealed significant group differences for most outcomes during or immediately after the stress test (i.e., mood, calmness, perceived stress, salivary cortisol, heart rate, heart rate variability) and during recovery (i.e., salivary cortisol and heart rate). Interestingly, the condition that experienced work interruptions showed a higher increase of cortisol levels but appraised the stress test as less threatening than individuals that experienced only psychosocial stress. Exploratory mediation analyses revealed a blunted response in subjective measures of stress, which was partially explained by the differences in threat appraisal.

DISCUSSION

The results showed that experimentally induced work stress led to significant responses of subjective measures of stress, the hypothalamic-pituitary-adrenal axis and the autonomic nervous system. However, there appears to be a discrepancy between the psychological and biological responses to preceding work interruptions. Appraising psychosocial stress as less threatening but still as challenging could be an adaptive way of coping and reflect a state of engagement and eustress.

Maternal plasma levels of oxytocin during breastfeeding-A systematic review

Introduction

Oxytocin is a key hormone in breastfeeding. No recent review on plasma levels of oxytocin in response to breastfeeding is available.

Materials and methods

Systematic literature searches on breastfeeding induced oxytocin levels were conducted 2017 and 2019 in PubMed, Scopus, CINAHL, and PsycINFO. Data on oxytocin linked effects and effects of medical interventions were included if available.

Results

We found 29 articles that met the inclusion criteria. All studies had an exploratory design and included 601 women. Data were extracted from the articles and summarised in tables. Breastfeeding induced an immediate and short lasting (20 minutes) release of oxytocin. The release was pulsatile early postpartum (5 pulses/10 minutes) and coalesced into a more protracted rise as lactation proceeded. Oxytocin levels were higher in multiparous versus primiparous women. The number of oxytocin pulses during early breastfeeding was associated with greater milk yield and longer duration of lactation and was reduced by stress. Breastfeeding-induced oxytocin release was associated with elevated prolactin levels; lowered ACTH and cortisol (stress hormones) and somatostatin (a gastrointestinal hormone) levels; enhanced sociability; and reduced anxiety, suggesting that oxytocin induces physiological and psychological adaptations in the mother. Mechanical breast pumping, but not bottle-feeding was associated with oxytocin and prolactin release and decreased stress levels. Emergency caesarean section reduced oxytocin and prolactin release in response to breastfeeding and also maternal mental adaptations. Epidural analgesia reduced prolactin and mental adaptation, whereas infusions of synthetic oxytocin increased prolactin and mental adaptation. Oxytocin infusion also restored negative effects induced by caesarean section and epidural analgesia.

Conclusions

Oxytocin is released in response to breastfeeding to cause milk ejection, and to induce physiological changes to promote milk production and psychological adaptations to facilitate motherhood. Stress and medical interventions during birth may influence these effects and thereby adversely affect the initiation of breastfeeding.

To Individualize the Management Care of High-Risk Infants With Oral Feeding Challenges: What Do We Know? What Can We Do?

The increase in preterm infants' survival over the last 30 years has shed light over their inability to feed by mouth safely and efficiently. With adverse events such as increased risks for oxygen desaturation, bradycardia, penetration/aspiration, infants' hospitalization in neonatal intensive care units (NICUs) are understandably prolonged. Unfortunately, this leads to delayed mother-infant reunion, maternal stress, breastfeeding obstacles, and increased medical costs. Such impediments have stimulated clinicians and researchers to better understand the underlying causes and develop evidence-based solutions to assist these infants. However, it is notable that the research-to-practice translation of this knowledge has been limited as there are still no validated guidelines or protocols as how to best diagnose and care for these infants. This report revisits the immature physiologic functions at the root of these infants' oral feeding difficulties, the current practices, and the recent availability of evidence-based efficacious tools and interventions. Taking advantage of the latter, it presents a renewed perspective of how management strategies can be tailored to the specific needs of individual patients.

Individualized intervention to improve rates of exclusive breastfeeding: A randomised controlled trial

BACKGROUND

Despite breastfeeding is significant benefits for maternal and infant, the discontinuation of breastfeeding is high. Some of studies showed that the effect of intervention in improving the rate of exclusively breastfeeding is unclear. The aim of this study is to investigate the effectiveness of individualized intervention compared with routine care in improving rates of exclusive breast feeding.

METHODS

Women were divided into two groups. We provided individual antenatal breastfeeding education and postnatal lactation support to intervention group. Control group received routine care. Significance was set at P < .05.

RESULTS

We recruited 352 women of whom 176 were randomized to intervention group, 176 to control group. In total, 293 (83.2%) completed 4 months of follow-up. At discharge from hospital, 43.2% of women randomized to intervention group were exclusively breastfeeding compared with 30.0% of women in control group (relative risk 1.78; 95% confidence interval [CI] 1.12-2.82). At 4 months, 70.9% of women in the intervention group were exclusively breastfeeding compared with 46.2% of the women in the control group (2.84; 1.76-4.60). At discharge from hospital, 95.1% of women in the intervention group were breastfeeding on demand compared with 68.1% of women receiving routine care (9.00; 4.09-19.74). At 4 months, 94.6% of women in intervention group were breastfeeding on demand compared with 75.9% of women in the control group (5.57; 2.48-12.49).

CONCLUSION

The regular ongoing individualized antenatal education and postnatal support can effective increase the rates of exclusive breastfeeding from delivery to postpartum 4 months and change the breastfeeding behavior.

Relative effects of breastfeeding intention and practice on maternal responsiveness

Our objective was to examine the differential effects of antenatal breastfeeding intention (BI) and breastfeeding practice (BP) on maternal postnatal responsiveness. We conducted a secondary analysis of longitudinal data from a subsample of 962 mother-infant dyads from a U.K.-based birth cohort study the Avon Longitudinal Study of Parents and Children. Exposures were BI and BPs measured at 32 weeks of gestation and 18 months' postpartum. The outcome was maternal responsiveness assessed at 12 months' postpartum. We used logistic regression analyses unadjusted and adjusted for confounders. Intention to breastfeed was associated with increased odds of postnatal maternal responsiveness independent of BP, adjusted odds ratio (OR) = 2.34, 95% CI [1.42, 3.86]. There was no evidence that BP was an independent predictor of maternal responsiveness, OR = 0.93, 95% CI [0.55, 1.57]. Life-course epidemiology analyses demonstrated that maternal responsiveness is most positive when both BI and BP are present. This is the first population-based study to provide evidence that BI during pregnancy is more strongly associated with maternal postnatal responsiveness than is BP. Further research is needed to understand the determinants of BI in pregnancy and its relationships with maternal responsiveness.

Psychological effects of breastfeeding on children and mothers

While the nutritional and physical health benefits of breastfeeding are well established, accumulating research demonstrates the far-reaching psychological effects of breastfeeding on children and their mothers. Here, we provide a non-exhaustive review of the empirical evidence, showing that breastfeeding impacts children's brain, cognitive, and socio-emotional development. In mothers, research is presented indicating that breastfeeding influences mood, affect, stress, and maternal care. The current review aims to provide a broad overview of existing findings on the psychological effects of breastfeeding, highlighting the important role that breastfeeding plays across several dimensions of psychological functioning. We also discuss the potential mechanisms that may underpin the observed effects, provide a constructive commentary on the limitations of the existing work, and put forth some considerations when evaluating this line of research.

Continued Enteral Feeding Is Beneficial in Hypoglycemic Infants Admitted to Intensive Care for Parenteral Dextrose Therapy

There is variability in practice among care providers on feeding infants admitted with neonatal hypoglycemia (NH) for parenteral dextrose. We compared clinical outcomes in infants who were fed (NH-Fed) and hypoglycemic infants who were kept nothing per os (NPO) (NH-NPO) at the time of initiation of intravenous (IV) dextrose. We performed a retrospective review of all newborn infants admitted to the neonatal intensive care unit with NH for IV dextrose. Infants were grouped as per the feeding approach at initiation of IV dextrose: NH-Fed or NH-NPO infants. We found that infants in the NH-Fed group had lower maximum glucose infusion rate, less duration of glucose infusion therapy compared with the NH-NPO group, and significantly less number of days of hospital stay compared with the NH-NPO group (5.87 ± 1.4 days vs 4.9 ± 1.4 days, P < .006). In conclusion, feeding infants with hypoglycemia who require IV dextrose offers tangible benefits of shorter duration of parenteral dextrose and shorter length of hospitalization.

[Health effects of breastfeeding on the mother]

We evaluated the effect of breastfeeding on maternal health outcomes. We distinguished between long-term effects (breast carcinoma, ovarian carcinoma, endometrial carcinoma, osteoporosis, and type 2 diabetes mellitus) and short-term effects (lactational amenorrhea, postpartum depression, and postpartum weight change).Predominant breastfeeding increases the duration of lactational amenorrhea, which has a short-term effect on the reduction of fertility. There are many studies that show that breastfeeding is protective against breast, ovarian carcinoma, and endometrial carcinoma. The effects depend on the duration of breastfeeding. There is evidence that breastfeeding reduces the risk of type 2 diabetes and metabolic syndrome and cardiac diseases. However, an association between breastfeeding and bone mineral density or maternal depression or postpartum weight change was not clearly evident.

[Breastfeeding Affects the Sleep of Mothers in Postpartum Period]

Many mothers in the postpartum period complain of fatigue and shortened sleeping time because of child care. Breastfeeding, especially in the early postpartum period, accounts for a large share of this problem. The purpose of this study is to assess the effects of breastfeeding on the sleep of mothers in the postpartum period, using 2 questionnaires: a self-created questionnaire for a survey of breastfeeding, and the OSA sleep inventory MA version for sleeping mothers. We performed the investigation twice, at 5-8 days and at one month after childbirth. The results showed that there was no significant difference in sleep between labor histories and delivery methods, but on the other hand, the exclusive breastfeeding group had a higher score about recovery and sleep length in the night during hospitalization (P < 0.05). In addition, the group of mothers in the lying down breastfeeding position (= Soechichi) group had higher scores in regards to their recovery than the other group in the night (P < 0.05). The exclusive breastfeeding group and the soechichi group also had a higher quality of sleep in both day and night at one month after childbirth. Comparing the quality of sleep between the term of hospitalization and one month after childbirth, it improved after a month, because the mothers had gotten used to breastfeeding and understood their baby's rhythm of breastfeeding after having spent a month together. We conclude that exclusive breastfeeding and the lying down breastfeeding position will provide a better quality of sleep for mothers.

Factors affecting breastfeeding adherence among Chinese mothers: A multicenter study

Breastfeeding is beneficial for both infant and mother, but discontinuation of breastfeeding is very common.To investigate maternal breastfeeding intention and the rate of breastfeeding based on the theory of reasoned action, and analyze the predominant factors associated with breastfeeding and breastfeeding problems.This observational study was conducted in 3 hospitals. Three researchers recruited women at 3 time points in the hospitals: initial documentation of pregnancy at the outpatient department, prenatal admission, and postpartum discharge. SPSS version 21 was used for statistical analyses. Significance was set at P < .05. In the multivariate analysis, binary logistic regression was used and odds ratios (ORs) with 95% confidence intervals (CI) were calculated.We recruited 1260 women, with 420 pregnant women at each time point. 55.1% of the infants were exclusively breastfed, 40.6% were mixed fed, and 4.3% were formula fed when discharged from hospital. A total of 53.8% of the mothers declared having breastfeeding problems. The multivariate analysis showed that nonsuccessful breastfeeding was associated with neonatal birth length, food intake before breastfeeding, infrequent sucking, the intention of breastfeeding, understanding level of the benefits of breastfeeding and that breastfeeding problems were related with the understanding level of the benefits of breastfeeding, neonatal birth length, normal vaginal delivery, breast size, the experience of breastfeeding, use of pacifier and the needs of family member's support in breastfeeding.Most mothers who intended to practice exclusive breastfeeding initially chose to add formula and had breastfeeding problems when discharged from hospital. Successful breastfeeding depends on antenatal and postnatal breastfeeding education and on support provided by healthcare professionals.

Novel dry electrodes for recording electrodermal activity

Novel carbon/salt adhesive (CSA) electrodes have been found suitable for collecting electrodermal activity (EDA) signals. Ag/AgCl electrodes are considered the standard for collecting EDA signals, because it highly avoids electrodes' polarization. Ag is an expensive commodity. Furthermore, a hydrogel layer is needed for the Ag/AgCl electrodes to collect EDA signals. Adding hydrogel to the electrodes is a cumbersome process. Aforementioned circumstances highlight the need for a more accessible media to collect these signals, allowing EDA use to spread. Dry electrodes made with a mixture of carbon, salt and adhesive has shown to be suitable for collecting bioelectric signals. We have implemented a constant DC-source EDA circuit, with the intention of testing how these electrodes perform for collecting EDA signals. Recruited subjects (N=4) underwent a test including electric shocks, watching a disturbing video and performing the Stroop task. Time and frequency domain correlation were computed. For the obtained skin conductance responses (SCRs), amplitude, onset-to-peak time, and onset difference between the CSA and Ag/AgCl electrodes' acquired SCRs were computed. We found no significant differences on SCRs amplitude and onset-to-peak time between CSA and Ag/AgCl. Furthermore, the difference in onset time for simultaneous SCRs obtained using both media was not different to zero. We conclude that CSA electrodes are a suitable surrogate of Ag/AgCl electrodes for collecting EDA signals on healthy subjects using the implemented DC circuit.

Highly sensitive index of sympathetic activity based on time-frequency spectral analysis of electrodermal activity

Time-domain indices of electrodermal activity (EDA) have been used as a marker of sympathetic tone. However, they often show high variation between subjects and low consistency, which has precluded their general use as a marker of sympathetic tone. To examine whether power spectral density analysis of EDA can provide more consistent results, we recently performed a variety of sympathetic tone-evoking experiments (43). We found significant increase in the spectral power in the frequency range of 0.045 to 0.25 Hz when sympathetic tone-evoking stimuli were induced. The sympathetic tone assessed by the power spectral density of EDA was found to have lower variation and more sensitivity for certain, but not all, stimuli compared with the time-domain analysis of EDA. We surmise that this lack of sensitivity in certain sympathetic tone-inducing conditions with time-invariant spectral analysis of EDA may lie in its inability to characterize time-varying dynamics of the sympathetic tone. To overcome the disadvantages of time-domain and time-invariant power spectral indices of EDA, we developed a highly sensitive index of sympathetic tone, based on time-frequency analysis of EDA signals. Its efficacy was tested using experiments designed to elicit sympathetic dynamics. Twelve subjects underwent four tests known to elicit sympathetic tone arousal: cold pressor, tilt table, stand test, and the Stroop task. We hypothesize that a more sensitive measure of sympathetic control can be developed using time-varying spectral analysis. Variable frequency complex demodulation, a recently developed technique for time-frequency analysis, was used to obtain spectral amplitudes associated with EDA. We found that the time-varying spectral frequency band 0.08-0.24 Hz was most responsive to stimulation. Spectral power for frequencies higher than 0.24 Hz were determined to be not related to the sympathetic dynamics because they comprised less than 5% of the total power. The mean value of time-varying spectral amplitudes in the frequency band 0.08-0.24 Hz were used as the index of sympathetic tone, termed TVSymp. TVSymp was found to be overall the most sensitive to the stimuli, as evidenced by a low coefficient of variation (0.54), and higher consistency (intra-class correlation, 0.96) and sensitivity (Youden's index > 0.75), area under the receiver operating characteristic (ROC) curve (>0.8, accuracy > 0.88) compared with time-domain and time-invariant spectral indices, including heart rate variability.

Mood, Food, and Fertility: Adaptations of the Maternal Brain

Successfully rearing young places multiple demands on the mammalian female. These are met by a wide array of alterations in maternal physiology and behavior that are coordinated with the needs of the developing young, and include adaptations in neuroendocrine systems not directly involved in maternal behavior or lactation. In this article, attenuations in the behavioral and neuroendocrine responses to stressors, the alterations in metabolic pathways facilitating both increased food intake and conservation of energy, and the changes in fertility that occur postpartum are described. The mechanisms underlying these processes as well as the factors that contribute to them and the relative contributions of these stimuli at different times postpartum are also reviewed. The induction and maintenance of the adaptations observed in the postpartum maternal brain are dependent on mother-young interaction and, in most cases, on suckling stimulation and its consequences for the hormonal profile of the mother. The peptide hormone prolactin acting on receptors within the brain makes a major contribution to changes in metabolic pathways, suppression of fertility and the attenuation of the neuroendocrine response to stress during lactation. Oxytocin is also released, both into the circulation and in some hypothalamic nuclei, in response to suckling stimulation and this hormone has been implicated in the decrease in anxiety behavior seen in the early postpartum period. The relative importance of these hormones changes across lactation and it is becoming increasingly clear that many of the adaptations to motherhood reviewed here reflect the outcome of multiple influences. © 2016 American Physiological Society. Compr Physiol 6:1493-1518, 2016.

Power Spectral Density Analysis of Electrodermal Activity for Sympathetic Function Assessment

Time-domain features of electrodermal activity (EDA), the measurable changes in conductance at the skin surface, are typically used to assess overall activation of the sympathetic system. These time domain features, the skin conductance level (SCL) and the nonspecific skin conductance responses (NS.SCRs), are consistently elevated with sympathetic nervous arousal, but highly variable between subjects. A novel frequency-domain approach to quantify sympathetic function using the power spectral density (PSD) of EDA is proposed. This analysis was used to examine if some of the induced stimuli invoke the sympathetic nervous system's dynamics which can be discernible as a large spectral peak, conjectured to be present in the low frequency band. The resulting indices were compared to the power of low-frequency components of heart rate variability (HRVLF) time series, as well as to time-domain features of EDA. Twelve healthy subjects were subjected to orthostatic, physical and cognitive stress, to test these techniques. We found that the increase in the spectral powers of the EDA was largely confined to 0.045-0.15 Hz, which is in the prescribed band for HRVLF. These low frequency components are known to be, in part, influenced by the sympathetic nervous dynamics. However, we found an additional 5-10% of the spectral power in the frequency range of 0.15-0.25 Hz with all three stimuli. Thus, dynamics of the normalized sympathetic component of the EDA, termed EDASympn, are represented in the frequency band 0.045-0.25 Hz; only a small amount of spectral power is present in frequencies higher than 0.25 Hz. Our results showed that the time-domain indices (the SCL and NS.SCRs), and EDASympn, exhibited significant increases under orthostatic, physical, and cognitive stress. However, EDASympn was more responsive than the SCL and NS.SCRs to the cold pressor stimulus, while the latter two were more sensitive to the postural and Stroop tests. Additionally, EDASympn exhibited an acceptable degree of consistency and a lower coefficient of variation compared to the time-domain features. Therefore, PSD analysis of EDA is a promising technique for sympathetic function assessment.

Associations Among Lactation, Maternal Carbohydrate Metabolism, and Cardiovascular Health

In mammalian reproductive physiology, lactation follows pregnancy; growing evidence suggests that disruption of this physiology affects a woman's lifetime risk of metabolic disease. These differences may reflect lactation-induced mobilization of fat stores and modulation of maternal stress reactivity. In addition, confounders may play a role: women who breastfeed for long durations are more likely to engage in other healthy behaviors, and obesity and insulin resistance may interfere with breastfeeding physiology. These findings underscore the importance of evidenced-based care to enable women to achieve their infant feeding goals.

Breastfeeding and maternal sensitivity predict early infant temperament

AIM

Research findings are inconclusive when it comes to whether breastfeeding is associated with the mother-infant relationship or infant temperament. We examined the association between breastfeeding at three months postpartum and infant temperament at 18 months postpartum and whether this link was affected by the mothers' anxiety and mediated by her sensitivity.

METHODS

We assessed 170 mothers for breastfeeding and anxiety using the Spielberger State-Trait Anxiety Inventory (STAI) at three months postpartum, maternal sensitivity using the Ainsworth Sensitivity Scale at six months postpartum and infant temperament using the Early Childhood Behaviour Questionnaire at 18 months postpartum.

RESULTS

Mothers who breastfed at three months postpartum were more sensitive in their interactions with their infants at six months postpartum, and elevated sensitivity, in turn, predicted reduced levels of negative affectivity in infant temperament at 18 months postpartum. This indirect mediation persisted after controlling for confounders (effect ab = -0.0312 [0.0208], 95% CI = -0.0884 to -0.0031). A subsequent analysis showed that the mediation through sensitivity only occurred in women experiencing higher anxiety, with a STAI score ≥33.56 at three months (ab = -0.0250 [0.0179], 95% CI = -0.0759 to -0.0013).

CONCLUSION

Our results suggest that breastfeeding and maternal sensitivity may have a positive impact on the early development of infant temperament.

Feeding modalities and the onset of the neonatal abstinence syndrome

Breast milk has been reported to ameliorate the severity and outcome of neonatal abstinence syndrome (NAS). The mechanism of this beneficial effect of breast milk on NAS remains unclear, as the negligible amount of methadone transmitted via breast milk is unlikely to have an impact on NAS. The aim of this study was to compare the impact of different feeding modalities on the onset of NAS. A retrospective medical record review was conducted on 194 methadone-maintained mother/infant dyads. Infants were categorized on the first 2 days of life as predominantly breastfed, fed expressed human breast milk (EBM), or formula fed. The feeding categories were then analyzed using the onset of NAS as the outcome measure. After adjusting for confounders, there was no significant effect of the modality of feeding on the rates of NAS requiring treatment (p = 0.11). Breastfeeding significantly delayed the onset of NAS (p = 0.04). The act of breastfeeding in the first 2 days of life had no effect on whether an infant required treatment for NAS when compared to those fed EBM or formula. This only suggests that the advantages of breastfeeding on NAS cannot be substantiated in a small cohort and should not discourage breastfeeding.

Breastfeeding status and maternal cardiovascular variables across the postpartum

BACKGROUND

There have been recent reports that lactational history is associated with long-term women's health benefits. Most of these studies are epidemiological. If particular cardiometabolic changes that occur during lactation ultimately influence women's health later is unknown.

METHODS

Seventy-one healthy women participated in a prospective postpartum study that provided an opportunity to study anthropometric, endocrine, immune, and behavioral variables across time. Variables studied were heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), C-reactive protein, body mass index (BMI), perceived stress, and hormones. A cohort of women without a change in breastfeeding (N=22) or formula feeding (N=23) group membership for 5 months was used for analysis of effects of feeding status. The data were analyzed using factorial repeated measures analysis of variance and analysis of covariance.

RESULTS

SBP and HR declined across the postpartum and were significantly lower in breastfeeding compared to formula feeding mothers (p<0.05). These differences remained statistically significant when BMI was added to the model. Other covariates of income, stress, marital status, and ethnicity were not significantly associated with these variables over time. DBP was also lower, but the significance was reduced by the addition of BMI as a covariate. Stress also was lower in breastfeeders, but this effect was reduced by the addition of income as a covariate.

CONCLUSIONS

These data suggest that there are important physiological differences in women during months of breastfeeding. These may have roles in influencing or programming later risks for a number of midlife diseases.

Breastfeeding experience differentially impacts recognition of happiness and anger in mothers

Breastfeeding is a dynamic biological and social process based on hormonal regulation involving oxytocin. While there is much work on the role of breastfeeding in infant development and on the role of oxytocin in socio-emotional functioning in adults, little is known about how breastfeeding impacts emotion perception during motherhood. We therefore examined whether breastfeeding influences emotion recognition in mothers. Using a dynamic emotion recognition task, we found that longer durations of exclusive breastfeeding were associated with faster recognition of happiness, providing evidence for a facilitation of processing positive facial expressions. In addition, we found that greater amounts of breastfed meals per day were associated with slower recognition of anger. Our findings are in line with current views of oxytocin function and support accounts that view maternal behaviour as tuned to prosocial responsiveness, by showing that vital elements of maternal care can facilitate the rapid responding to affiliative stimuli by reducing importance of threatening stimuli.

Effects of an intervention to promote breastfeeding on maternal adiposity and blood pressure at 11.5 y postpartum: results from the Promotion of Breastfeeding Intervention Trial, a cluster-randomized controlled trial

BACKGROUND

Differences between mothers who do and do not succeed in breastfeeding are likely to confound associations of lactation with later maternal adiposity.

OBJECTIVE

We compared adiposity and blood pressure (BP) in women randomly assigned to an intervention to promote prolonged and exclusive breastfeeding or usual care.

DESIGN

We performed a cluster-randomized trial at 31 hospitals in Belarus in 1996-1997.

RESULTS

Of 17,046 women enrolled at delivery, we assessed 11,867 women (69.6%) at 11.5 y postpartum. The prevalence of exclusive breastfeeding ≥3 mo was 44.5% in 6321 women in the intervention group and 7.1% in 5546 women in the control group. At 11.5 y postpartum, mean (±SD) body mass index (BMI; in kg/m(2)) was 26.5 ± 5.5, the percentage of body fat was 33.6% ± 8.3%, and systolic BP was 124.6 ± 14.6 mm Hg. On intention-to-treat analysis (without imputation) with adjustment for clustering by hospital, mean outcomes were lower in intervention compared with control mothers for BMI (mean difference: -0.27; 95% CI: -0.91, 0.37), body fat (-0.49%; 95% CI: -1.25%, 0.27%), and systolic BP (-0.81 mm Hg; 95% CI: -3.33, 1.71 mm Hg), but effect sizes were small, CIs were wide, and results were attenuated further toward the null after adjustment for baseline characteristics. Results were similar in sensitivity analyses [ie, by using conventional observational analyses disregarding treatment assignment, instrumental variable analyses to estimate the causal effect of breastfeeding, and multiple imputation to account for missing outcome measures (n = 17,046)].

CONCLUSION

In women who initiated breastfeeding, an intervention to promote longer breastfeeding duration did not result in an important lowering of adiposity or BP. This trial was registered at clinicaltrials.gov as NCT01561612 and at Current Controlled Trials as ISRCTN37687716.

Biological aspects of postpartum depression

In comparison with the vast epidemiological literature on postpartum depression (PPD), relatively few studies have examined the biological aspects of the disorder. However, research into the biological mechanisms of PPD is a challenging task, as normal pregnancy and the postpartum period cause adaptive endocrine changes, which would otherwise be considered pathological in nonpregnant women. This review focuses on the adaptive changes of childbearing and nursing, which ultimately may put women at increased risk of PPD. In light of the normal physiology, the authors also attempt to describe the current evidence of the biological changes associated with the development of depression in the postpartum period, including ovarian steroids, the hypothalamic-pituitary-adrenal axis, the serotonergic neurotransmitter system, the thyroid system and inflammatory markers. In addition, current knowledge on candidate genes associated with PPD is reviewed.

Breast feeding increases vasoconstriction induced by electrical field stimulation in rat mesenteric artery. Role of neuronal nitric oxide and ATP

Objectives

The aim of this study was to investigate in rat mesenteric artery whether breast feeding (BF) affects the vasomotor response induced by electrical field stimulation (EFS), participation by different innervations in the EFS-induced response and the mechanism/s underlying these possible modifications.

Methods

Experiments were performed in female Sprague-Dawley rats (3 months old), divided into three groups: Control (in oestrous phase), mothers after 21 days of BF, and mothers that had recovered their oestral cycle (After BF, in oestrous phase). Vasomotor response to EFS, noradrenaline (NA) and nitric oxide (NO) donor DEA-NO were studied. Neuronal NO synthase (nNOS) and phosphorylated nNOS (P-nNOS) protein expression were analysed and NO, superoxide anion (O₂^.–), NA and ATP releases were also determined.

Results

EFS-induced contraction was higher in the BF group, and was recovered after BF. 1 µmol/L phentolamine decreased the response to EFS similarly in control and BF rats. NA vasoconstriction and release were similar in both experimental groups. ATP release was higher in segments from BF rats. 0.1 mmol/L L-NAME increased the response to EFS in both control and BF rats, but more so in control animals. BF decreased NO release and did not modify O₂^.– production. Vasodilator response to DEA-NO was similar in both groups, while nNOS and P-nNOS expressions were decreased in segments from BF animals.

Conclusion

Breast feeding increases EFS-induced contraction in mesenteric arteries, mainly through the decrease of neuronal NO release mediated by decreased nNOS and P-nNOS expression. Sympathetic function is increased through the increased ATP release in BF rats.

Sexually dimorphic effects of oxytocin receptor gene (OXTR ) variants on Harm Avoidance

Background

Recent research has suggested that oxytocin receptor gene (OXTR) variants may account for individual differences in social behavior, the effects of stress and parenting styles. Little is known, however, on a putative role of the gene in heritable temperamental traits.

Methods

We addressed effects of two common OXTR variants, rs237900 and rs237902, on personality dimensions in 99 healthy subjects using the Temperament and Character Inventory.

Results

When sex was controlled for and an OXTR genotype*sex interaction term was included in the regression model, 11% of the variance in Harm Avoidance could be explained (uncorrected p ≤ 0.01). Female carriers of the minor alleles scored highest, and a novel A217T mutation emerged in the most harm avoidant male participant.

Conclusions

Findings lend support to a modulatory effect of common OXTR variants on Harm Avoidance in healthy caucasian women and invite resequencing of the gene in anxiety phenotypes to identify more explanatory functional variation.

Failed lactation and perinatal depression: common problems with shared neuroendocrine mechanisms?

In the early postpartum period, mother and infant navigate a critical neuroendocrine transition from pregnancy to lactation. Two major clinical problems that occur during this transition are failed lactation and perinatal mood disorders. These disorders often overlap in clinical settings. Failed lactation is common. Although all major medical organizations recommend 6 months of exclusive breastfeeding, only 13% of women in the United States achieve this recommendation. Perinatal mood disorders affect 10% of mothers, with substantial morbidity for mother and child. We hypothesize that shared neuroendocrine mechanisms contribute to both failed lactation and perinatal mood disorders. In this hypothesis article, we discuss data from both animal models and clinical studies that suggest neuroendocrine mechanisms that may underlie these two disorders. Research to elucidate the role of these underlying mechanisms may identify treatment strategies both to relieve perinatal depression and to enable women to achieve their infant feeding goals.

An overlooked aspect of the human breast: areolar glands in relation with breastfeeding pattern, neonatal weight gain, and the dynamics of lactation

The early nursing-sucking relationship is not to be taken for granted in humans. A number of factors can either facilitate or mitigate its optimal establishment on the mother's or newborn's sides. Among these factors, a morphological feature of human mothers' breasts--the areolar glands (AG)--has been identified as potentially important. Three day-old infants display attraction during the presentation of the native secretions of the AG, suggesting that they could influence the newborn's behaviour during breastfeeding. The present study assessed this topic in a sample of 121 Caucasian mother-infant dyads. The areolae of these women were screened during the first 3 postnatal days in parallel with the infant's sucking performance, body weight fluctuations and time to lactation onset. On average, 97% of the women bore AG, 80.2% having 1-20 units per areola and 33% showing AG excreting a visible fluid. The endowment in AG appeared positively linked with neonatal growth after birth and with the speed of lactation onset: infants of primiparous women with lower AG numbers had a lower weight gain than those of mothers with higher AG numbers. Further, it took longer to primiparae with lower AG counts to set on lactation. This study confirms and extends the fact that AG, in interaction with maternal experience, might influence the initiation of the breastfeeding relationship.

Breastfeeding, brain activation to own infant cry, and maternal sensitivity

BACKGROUND

Research points to the importance of breastfeeding for promoting close mother-infant contact and social-emotional development. Recent functional magnetic resonance imaging (fMRI) studies have identified brain regions related to maternal behaviors. However, little research has addressed the neurobiological mechanisms underlying the relationship between breastfeeding and maternal behavior in human mothers. We investigated the associations between breastfeeding, maternal brain response to own infant stimuli, and maternal sensitivity in the early postpartum.

METHODS

Seventeen biological mothers of healthy infants participated in two matched groups according to feeding method - exclusive breastfeeding and exclusive formula-feeding at 2-4 weeks postpartum. fMRI scanning was conducted in the first postpartum month to examine maternal brain activation in response to her own baby's cry versus control baby-cry. Dyadic interactions between mothers and infants at 3-4 months postpartum were videotaped in the home and blindly coded for maternal sensitivity.

RESULTS

In the first postpartum month, breastfeeding mothers showed greater activations in the superior frontal gyrus, insula, precuneus, striatum, and amygdala while listening to their own baby-cry as compared to formula-feeding mothers. For both breastfeeding and formula-feeding mothers, greater activations in the right superior frontal gyrus and amygdala were associated with higher maternal sensitivity at 3-4 months postpartum.

CONCLUSIONS

Results suggest links between breastfeeding and greater response to infant cues in brain regions implicated in maternal-infant bonding and empathy during the early postpartum. Such brain activations may facilitate greater maternal sensitivity as infants enter their social world.

Duration of lactation and maternal adipokines at 3 years postpartum

OBJECTIVE

Lactation has been associated with reduced maternal risk of type 2 diabetes, the metabolic syndrome, and cardiovascular disease. We examined the relationship between breastfeeding duration and maternal adipokines at 3 years postpartum.

RESEARCH DESIGN AND METHODS

We used linear regression to relate the duration of lactation to maternal leptin, adiponectin, ghrelin, and peptide YY (PYY) at 3 years postpartum among 570 participants with 3-year postpartum blood samples (178 fasting), prospectively collected lactation history, and no intervening pregnancy in Project Viva, a cohort study of mothers and children.

RESULTS

A total of 88% of mothers had initiated breastfeeding, 26% had breastfed ≥ 12 months, and 42% had exclusively breastfed for ≥ 3 months. In multivariate analyses, we found that duration of total breastfeeding was directly related to PYY and ghrelin, and exclusive breastfeeding duration was directly related to ghrelin (predicted mean for never exclusively breastfeeding: 790.6 pg/mL vs. ≥ 6 months of exclusive breastfeeding: 1,008.1 pg/mL; P < 0.01) at 3 years postpartum, adjusting for pregravid BMI, gestational weight gain, family history of diabetes, parity, smoking status, and age. We found a nonlinear pattern of association between exclusive breastfeeding duration and adiponectin in multivariate-adjusted models.

CONCLUSIONS

In this prospective cohort study, we found a direct relationship between the duration of lactation and both ghrelin and PYY at 3 years postpartum.

Parental precaution: neurobiological means and adaptive ends

Humans invest precious reproductive resources in just a few offspring, who remain vulnerable for an extended period of their lifetimes relative to other primates. Therefore, it is likely that humans evolved a rich precautionary psychology that assists in the formidable task of protecting offspring. In this review, we integrate precautionary behaviors during pregnancy and postpartum with the adaptive functions they may serve and what is known of their biological mediators, particularly brain systems motivating security and attachment. We highlight the role of reproductive hormones in (i) priming parental affiliation with young to incentivize offspring protection, (ii) focusing parental attention on cues of potential threat, and (iii) facilitating maternal defense against potentially dangerous conspecifics and predators. Throughout, we center discussion on adaptive responses to threats of disease, accident and assault as common causes of child mortality in the ancestral past.

Formative infant feeding experiences and education of NICU nurses

PURPOSE

To explore the formative infant feeding experiences and education of NICU nurses.

STUDY DESIGN AND METHODS

An ethnography was undertaken over 14 months in a level IV NICU in a free standing pediatric hospital in the Northeastern U.S. Purposeful sampling was used to select informants. General informants included 114 NICU nurses who were observed and informally interviewed an average of 3.5 times. Eighteen of these served as key informants and each was formally interviewed once with an additional average of 12 observations/informal interviews. Descriptions of feeding experiences and education were coded and analyzed for recurring patterns using NUD*IST software.

FINDINGS

The NICU nurses identified a norm for formula feeding during their formative experiences as children. The nurses described increased exposure to varied feeding methods during their adulthood, but breastfeeding was often associated with difficulties among their families and friends. The nurses in this study recounted minimal exposure to breastfeeding in nursing school. The nurses' personal experiences with breastfeeding were laden with strong emotional reactions intertwined with their feelings about motherhood.

CLINICAL IMPLICATIONS

Nurses' past experiences and education must be addressed if efforts are to be made to promote breastfeeding in the NICU. Breastfeeding education programs for nurses should include reflective components to help nurses identify structural barriers and reframe any negative personal experiences.

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.

Parity mediates the association between infant feeding method and maternal depressive symptoms in the postpartum

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.