Are mothers who exclusively breastfed their child protected from developing postpartum depression in comparison to mothers who non-exclusively breastfed?New Nursing Article Page

Brianna Atkins


Postpartum depression is a prevalent and serious mental health condition affecting 10 to 20 percent of women globally and in New Zealand anytime during their first year of motherhood (Plunket, 2014). The symptomologies of postpartum depression in mothers includes; perceiving one’s self as hopeless or worthless accompanied by a persistent low mood, anhedonia, decreased energy, reduced appetite and disturbed sleep (Mental Health Foundation of New Zealand, n.d.). Current research suggests that not only does postpartum depression have immediate and chronic negative effects on the mother, but also upon the infant’s social, emotional and cognitive development (Knapp, McDaid, & Parsonage, 2011). These detrimental outcomes for both mother and baby are what makes postpartum depression a significant clinical issue that nurses need to be aware of and able to provide accurate guidance and education to prevent its development. To be equipped to provide such support, it is vital that protective factors against the development of postpartum depression in mothers are explored. After extensive research, and the use of the PECOT model, I was able to narrow my broader research topic regarding general protective factors against postpartum depression to whether there was a link between exclusive breastfeeding and a decreased prevalence of the illness in mothers. Conclusions drawn from my literature review will thus direct my recommendations for future nursing practice in the prospect of reducing postpartum depression in New Zealand and the wider context. 

Clinical Issue

Postpartum depression is the most predominant and serious of all child-bearing related illnesses, typically affecting mothers in the first 12 months after childbirth (BPACNZ, 2010). Specific to a New Zealand context, the 2015 New Mothers’ Mental Health survey, states that 14% of the respondents met the criteria for postpartum depression on the Edinburgh Postpartum Depression Scale (Deverick & Guiney, 2016). In addition, the Twelfth Annual Report of the Perinatal and Maternal Mortality Review Committee reported that suicide second to postpartum depression is the leading cause of maternal perinatal death in New Zealand (PMMRC, 2018).  

Whilst the immediate effects of postpartum depression such as insomnia, fatigue, loss of appetite and weakness are hindering, the long-term adverse effects which stem from it are of concern too (Mental Health Foundation of New Zealand, n.d.). Untreated postpartum depression in mothers is associated with numerous comorbidities. According to Horowitz and Goodman (2004), 30% of women in community samples who experience postpartum depression continued to be depressed up to two years postpartum. Furthermore, unresolved postpartum depression can lead to the development of anxiety, suicidal ideation and thoughts of harming one’s self or the infant (Pope & Mazmanian, 2016). 

Not only is postpartum depression detrimental to the mother’s health, it has physical, social and emotional repercussions upon the infant as well. According to Korhonen, Luoma, Salmelin, and Tamminen (2012), there was a significant impairment in the infant-mother attachment of mothers suffering from postpartum depression. Furthermore, children whose mothers experienced postpartum depression were more likely to develop emotional, behavioural or psychosocial problems during their childhood due to this impaired attachment and disengagement (Korhonen, Luoma, Salmelin, & Tamminen, 2012). 

Due to the negative implications postpartum depression has upon the mother, the infant and their family, it is imperative that registered nurses can provide guidance on how to prevent the development of this illness and impede the follow-on effects experienced by both mother and child. This notion prompted me to research factors that are protective against the development of postpartum depression. I found that several important variables were associated with the development of the disease such as history of depression, self-esteem, marital status, unwanted pregnancy and lack of breastfeeding or exclusive formula feeding (Beck, 2001; McCoy, Martin, Miller Shipman, Payton, & Watson, 2006). However, breastfeeding appeared to be a common theme throughout all the research and was something that nurses could participate in and modify in comparison to the other variables. Nurses are often the first point of call for mothers after their time with their midwife. Therefore, if there is a link between breastfeeding and reduction of postpartum depression, we need to ensure that as a cohort we are educated in how to support breastfeeding mothers in attempt to reduce the statistics of postpartum depression.  

Research Question

By incorporating the PECOT model into my research process I was able to refine and restructure my broader question. Initially, my research focussed on studies alluding to all protective factors against postpartum depression in new mothers. However, after initial research, I noted the reoccurrence of breastfeeding and thus began to search using the key terms “postpartum depression”, “breastfeeding” and “protection” to guide my literature review. Finally, I was able to generate the specific review question “Are mothers who exclusively breastfed their child protected from developing postpartum depression in comparison to mothers who non-exclusively breastfed?” This has enabled me to find a broad range of literature discussing this question and come up with a conclusion and recommendations to implement into nursing practice.



PECOT category

Information relating to the question



Mothers who have given birth within the last 12 months who are either exclusively breastfeeding or breastfeeding via alternative methods.  

It is reported that while postpartum depression can occur at any time from birth, postpartum depression in mothers is most likely to occur within the first 12 months of the infants’ life.


Mothers who breastfeed their infant exclusively  

The aim of this research question is to determine if mothers who breastfeed their infants exclusively were protected from postpartum depression symptomologies.


Mothers who did not breastfeed their infant exclusively

The comparison group will help identify whether mothers who did not exclusively breastfeed their infants were more likely to experience postpartum depression symptomologies.


The aim of this literature review is to determine if exclusive breastfeeding is a protective factor against the development of postpartum depression in new mothers. If the literature suggests there is a correlation, early breastfeeding initiation and ongoing support from nurses may be the key to preventing the onset of the illness.

As a registered nurse, it is our responsibility to ensure that we provide the best advice, support and guidance to prevent adverse mental health issues in new mothers. Knowing which method of feeding is best for mother and baby’s immediate and long-term health is vital for nurses to be aware of to ensure the right guidance and postpartum education is given.


12 months

Postpartum depression is common within the first 12 months of the infant’s life. 


(Schneider, & Whitehead, 2013).  

Literature Review

After reviewing relevant literature, multiple studies have confirmed that there is in fact a link between exclusive breastfeeding and a decrease in depressive symptomology postpartum. There is also noted to be a link between exclusive breastfeeding and an increase in overall mood and decrease in perceived stress immediately after breastfeeding, which can be linked to the reduced depressive symptomology in breastfeeding mothers. In contrast, there is evidence that failure to establish and maintain successful breastfeeding, or early negative experiences with breastfeeding can be a trigger for the development of postpartum depression. 

Two studies were conducted which demonstrated the association between exclusive breastfeeding and reduced perceived stress and increased mood. The first study conducted by Mezzacappa and Katkin (2002) involved two experiments. The first was a between-subjects comparison assessing subjective perceived stress in the past month between a group of exclusively breastfeeding and bottle feeding mothers using the Perceived Stress Scale. The results of this experiment indicated that after controlling for demographic confounding variables, breastfeeding mothers reported significantly less perceived stress during the past month than bottle feeding mothers. The second experiment was a within-subject design examining the acute psychological effects of breastfeeding in comparison to bottle feeding. Positive and negative maternal moods before and after each different feeding session were measured using the Positive and Negative Affect Scale. The results of this experiment proved that the act of breastfeeding decreased negative mood in mothers from pre-feeding to post-feeding comparative to bottle feeding in the same mother. In contrast to this, it was observed that bottle feeding decreased positive mood from pre-feeding to post-feeding.  

The results of this study conducted by Mezzacappa and Katkin (2002) correlate with a larger study conducted by Groër (2005). The aim of this study was to examine the relationship between lactational status, stress levels and mood in postpartum mothers. A group of exclusively breastfeeding and exclusively formula feeding mothers undertook several assessments four to six weeks postpartum. These assessments examined for perceived general stress using the Perceived Stress Scale and overall maternal mood since birth using the Profile of Mood States. Results of this study confirmed that perceived stress scores “right now” and “since the baby was born” were higher in the bottle feeders. Furthermore, it was concluded that breastfeeders experienced lower levels of depression, anger and anxiety than bottle feeders as evidenced by the significantly lower scores on the Profile of Mood States assessment. A noteworthy element of this study and the study conducted by Mezzacappa et al. (2002) was the exploration of the relationship between prolactin, oxytocin and breastfeeding. Prolactin and oxytocin are hormones both released during lactation and found in significantly higher concentrations in those who breastfed (Groër, 2005). Both hormones are associated with feelings of calmness and lowered aggression, and as Mezzacappa et al. (2002) stated, act as an endogenous antidepressant during and after breastfeeding. If in a sense, breastfeeding acts as an endogenous antidepressant, it is logical that exclusive breastfeeding would thus protect mothers against postpartum depression. 

Several studies have also been produced which directly establish the notion that breastfeeding is likely to be a protective factor against the development of postpartum depression.  In a large cross-sectional study conducted by Mancini, Carlson, and Albers (2007), a large group of women were screened six weeks after birth for postpartum depression using the Postpartum Depression Screening Scale. It was discovered that the mothers who exclusively breastfed were half as likely to screen positively for postpartum depression in comparison to those who exclusively bottle fed. Additionally, this study revealed that there were two variables that were statistically significant predictors for a mother to screen positive for postpartum depression, one of them being exclusive bottle feeding (risk ratio, 2.0). 

Finally, an Icelandic study conducted by Thome, Alder, and Ramel (2006) involved mothers who were either exclusive breastfeeding, supplemented breastfeeding, bottle feeding or feeding semi-solids. These mothers completed self-administered questionnaires 8 to 12 weeks postpartum to assess parenting stress and postpartum depression. It was found that exclusively breastfeeding mothers had lower mean Edinburgh Postpartum Depression Scale scores with a mean of 5.9, compared to non-exclusively breastfeeding mothers, with a mean of 7.1. The results compare with the previous studies conducted, that exclusive breastfeeding is positively associated with lower Edinburgh Postpartum Depression Scale scores relative to non-exclusive breastfeeders. 

Whilst there is substantial evidence that breastfeeding is linked to improved mood, decreased stress and lower levels of postpartum depression, there is conflicting literature declaring that failed breastfeeding or early negative breastfeeding experiences may result in postpartum depression. A US study conducted by Watkins, Meltzer-Brody, Zolnoun and Stuebe (2011) aimed to understand the association between negative early breastfeeding experiences and the development of postpartum depression. At three weeks postpartum, a questionnaire was undertaken by mothers asking about levels of pain involved with breastfeeding and overall feelings about breastfeeding. At two months postpartum, the same mothers completed the Edinburgh Postpartum Depression Scale. Results showed that women who experienced breast pain and disliked breastfeeding in the first two weeks postpartum, were more likely to experience postpartum depression at two months. These results were suggestive that early breastfeeding difficulties and negative connotations towards breastfeeding were associated with increased depressive symptomologies at two months postpartum. 

Further literature, concurrent with Watkins et al. (2011), is a study conducted by Fergerson, Jamieson, and Lindsay (2002) which aimed to determine risk factors associated with a positive score (>10) on the Edinburgh Postpartum Depression Scale (EPDS). A score greater than 10 is indicative of mild postpartum depression (Boyce, Stubbs, & Todd, 1993). Within the 37 women who completed the EPDS during their first postpartum check-up, a “failed” breastfeeding attempt was the single factor associated with an EPDS score greater than 10 (relative risk 3.0).  

In society, it is an unfortunate reality that we have constructed and defined that what makes a “good” mother is her ability to feed her child naturally through breastfeeding. With external societal pressures, and the internal pressures to provide what has been deemed the best form of nutrition for their infant, mothers who struggle with, or fail at breastfeeding may question their motherhood. They may feel as though any other form of feeding is a let-down for their child, which in turn may lead to the depressive symptomology discussed in both studies conducted by Watkins et al. (2011) and Fergerson et al. (2002). 

Implications on Practice

The first four studies discussed suggests there is indeed a strong correlation between exclusive breastfeeding and a decrease in perceived stress and negative mood. More notably, the concept that exclusive breastfeeding serves as a protective factor against subsequent postpartum depression is feasible. From a clinical nursing perspective, this information is crucial, providing us with the motive to intervene early and deliver breastfeeding support and education in an attempt to increase breastfeeding efficacy. Ultimately, such actions will likely enhance long-term maternal mental health outcomes as well as infant outcomes. 

However, the findings from the last two studies conducted by Watkins et al. (2011) and Fergerson et al. (2002) propose a further element to think about. While breastfeeding may be a protective factor, if early attempts to breastfeed fail or the mother experiences negative feelings towards breastfeeding, breastfeeding may be counterproductive and indeed provoke the development of postpartum depression. This is where nurses must step in and ensure that specialised ongoing support is initiated and maintained for mothers who intended to breastfeed but failed. A health policy objective like this ensures that mothers will sustain breastfeeding and reap its benefits for themselves and their children. 


Based on the implications I have discovered during my literature review, I have come up with the following recommendations for nursing practice regarding breastfeeding support and education. According to Imdad, Yakoob and Bhutta, (2011), inadequate support and education for mothers wishing to breastfeed contributes to the high rates of early cessation of breastfeeding. Therefore, the authors state that education and support are the cornerstones for supporting breastfeeding. In conjunction with this, Hannula, Kaunonen, and Tarkka (2007) report that the most effective postpartum interventions resulting in sustained exclusive breastfeeding was the combination of education and ongoing support from a trained health professional. However, if the health professional gave inaccurate information, this led to decreased breastfeeding outcomes. From these results, I think it is imperative that all nurses are trained in breastfeeding support and education, so we are competent to act as breastfeeding supporters and provide services needed to enhance breastfeeding and protect against postpartum depression. 

My first recommendation relevant to the New Zealand context is that all nurses are specifically trained in breastfeeding education and support, as pregnancy is relevant in all areas of nursing. In all of the undergraduate nursing programmes, breastfeeding education should be implemented, teaching about the importance of breastfeeding, the risks of not breastfeeding, common problems that may occur and solutions to these. In addition to this, education surrounding postpartum depression, and the signs and symptoms of the disease, as well as solutions should be taught. In postgraduate nurses, completion of further learning should be encouraged and funded by health organisations, specifically aimed at primary health nurses, paediatric, neonatal and mental health nurses. Further learning available to nurses are the online learning modules “Breastfeeding Essentials” by Step 2 Education (Step 2 Education International Inc, n.d.) and the New Zealand Breastfeeding Authority and Ministry of Health online learning module “Breastfeeding” (Ministry of Health, 2012). Both modules cover the protection, promotion and support of breastfeeding in community settings.  

It is important that nurses are also aware of the external services we can refer mothers to which can support them with breastfeeding if they are experiencing difficulties or a failed attempt. The La Leche League New Zealand is a national organisation run by experienced and trained mothers discussing breastfeeding difficulties and solutions to overcome them, as well as providing encouragement. Support is available over the phone, or at group meetings (La Leche League NZ, n.d.). According to Chapman, Morel, Anderson, Damio, and Perez- Escamilla (2010) peer counsellors such as the ones seen in the La Leche League, effectively improved rates of breastfeeding initiation, exclusivity and duration, making referral to groups like this worthwhile. Additionally, there are digital applications which are accessible at any time or place aimed at supporting mothers. An example is the free BreastFedNZ app, designed to provide simple, “in the moment” support and information regarding breastfeeding (BreastFedNZ, 2018). It is beneficial in particular for mothers in remote areas of New Zealand who may not have easy access to health care services, proving a valuable recommendation for mothers who may be struggling. 

In relation to Māori health, there is evidence that only 16% of Māori women are breastfeeding at 6 months in comparison to 25% of European women (National Breastfeeding Advisory Committee of New Zealand, 2009). In conjunction with this, Maori women appear to be at higher risk of postpartum depression than European women (BPACNZ, 2010). As nurses we need to be aware of this, and the culturally specific resources for Māori women that are available in order to increase Māori breastfeeding rates, and target Māori maternal mental health outcomes. B4Baby is a free Kaupapa Māori education and support service delivering culturally appropriate breastfeeding education and support to new Mothers in South Auckland. The service offers in home or Marae visits, as well as Lactation Consultant home visits for more complex cases (Counties Manukau Health, 2016). 

Finally, it is the primary nurse’s role to provide support after the first 4-6 weeks with the midwife. Most women initiate exclusive breastfeeding initially, but there is a steep decline in the first 6 weeks (National Breastfeeding Advisory Committee of New Zealand, 2009). At the infants immunisation appointments or any other appearance at the health centre it is vital that the nurse asks every mother how they are coping with breastfeeding. If they are struggling, appropriate advice or referrals should be made. Weekly appointments should be made for the first few weeks after the mother has left the midwives care to check in on how breastfeeding is progressing. 


Postpartum depression is a predominant and debilitating condition affecting New Zealand women. If left untreated, this illness can have negative health outcomes for not only the mother, but her infant as well. Such adverse health outcomes for both groups is what makes the prevention of postpartum depression a significant health priority for health professionals, specifically nurses. From an extensive critique of the literature, it is apparent that my review question is plausible in that exclusive breastfeeding does indeed protect mothers against the development of postpartum depression. However, it was evident that early negative experiences with breastfeeding, or a failed attempt at breastfeeding, may actually trigger the onset of postpartum depression. In relation to nursing, these findings have several implications for practice to improve maternal mental health outcomes. These implications include early intervention in delivering breastfeeding support and education, as well as providing ongoing support for mothers who had negative breastfeeding experiences. Ultimately, such interventions will lead to an increase in exclusive breastfeeding, and a subsequent decrease in postpartum depression in New Zealand mothers and the negative health outcomes accompanying the illness.  


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