The Mystery of D-MER: What Can Hormonal Research Tell Us About Dysphoric Milk-Ejection Reflex?

Biology of Oxytocin

Oxytocin is produced in two cell groups in the hypothalamus: the supraoptic nucleus and the paraventricular nucleus (PVN). Neurons, or nerves, containing oxytocin from both these cell groups reach the posterior pituitary and release oxytocin into the circulation. In addition, the PVN sends nerves to many important regulatory centers in the brain. When the PVN is activated, oxytocin is, therefore, released, not only into circulation but also into the brain (Uvnas-Moberg, 2015). The PVN controls both the stress and oxytocin systems; when one is upregulated, the other is normally downregulated. Each system is associated with a particular set of emotional responses (see Figures 1–3).

Figure 1.

Normally, when oxytocin is upregulated, the stress response is downregulated. Conversely, when stress is up, oxytocin is down. In D-MER, it appears that oxytocin is upregulating the stress response. Photo credit: Fotolia.

Photo credit: Fotolia.

Figure 2.

Oxytocin is normally associated with positive feelings, bonding, and affiliation.

Photo credit: Fotolia.

Figure 3.

An upregulated stress response is associated with increased depression, anxiety, and other negative feelings. Photo credit: Fotolia.

Photo credit: Fotolia.

Oxytocin is released into areas such as the amygdala, the center in the brain that regulates fear and social interaction. In addition, oxytocin is released into areas of the brain that regulate pain, well-being, calm, blood pressure, pulse rate, digestion and metabolism, thirst, and appetite. Women often experience a short period of thirst while breastfeeding, and they are hungrier, which is normal. Oxytocin is regulating their intake of nutrients. Some women experience a short period of decreased pulse rate and blood pressure. These adaptations, from a basic physiological point of view, help mothers cope with breastfeeding. In addition, oxytocin released during breastfeeding facilitates interaction with the baby and makes the mother happier and less anxious (Uvnas-Moberg, 2015). In fact, researchers have found a link between circulating oxytocin levels and the level of attachment between mother and baby (Strathearn, Mamun, Najman, & O'Callaghan, 2009).

Nurture and Protect

Oxytocin not only helps mothers feed, warm, and care for their babies but also helps mothers protect their babies, and can trigger both aggression and the fight–flight response. The protective action of oxytocin is linked to negative feelings in the mother, such as fear and anger. Oxytocin promotes this protective response, and it is activated when the mother perceives the environment as hostile or dangerous for her baby (Uvnas-Moberg, 2015).

The symptoms of D-MER resemble a short-term expression of maternal aggression or the fight–flight response. In these women, breastfeeding appears to trigger this response via oxytocin. This symptom pattern resembles chronic hyperarousal symptoms in post-traumatic stress disorder (PTSD), with a chronically activated stress system on the lookout for possible danger (Ruglass & Kendall-Tackett, 2015). Symptoms of D-MER do not mean that mothers have negative feelings toward their babies. These negative feelings are triggered in a part of the brain that is not within the mother’s conscious control. Rather, we believe that the burst of oxytocin activates, by mistake, mothers’ defense reactions, rather than the more positive feelings normally associated with breastfeeding (Uvnas-Moberg, 2015). Defense and protective reactions are, in fact, part of the mother’s care of their babies. If necessary, the mothers must be able to protect them, but these reactions should only be induced if there is a real danger.

Why Does This Happen?

The truth is that we don’t know why D-MER happens to some mothers and not others. It could be trauma, but the D-MER.org site correctly notes that many women without a history of trauma have D-MER. A mother’s prior experience of any significant stress may make her overreactive to current stressors, which, in a way, protects her and her baby. Stress can come from many sources.

Stress during pregnancy can trigger this defensive response. Animal studies have found that stress during pregnancy can reverse the suckling-related positive effects of oxytocin release and lead to negative, inhibitory effects (Hillerer, Reber, Neumann, & Slattery, 2011). A stressful labor can also trigger a negative response. For example, in a recent study, mothers who had synthetic oxytocin (Pitocin) during their labors had significantly more anxiety and depression postpartum compared with mothers who did not have synthetic oxytocin (Kroll-Desrosiers et al., 2017). Synthetic oxytocin makes labor more painful and blocks the action of a naturally occurring oxytocin, which enhances stress levels and increases the risk of postpartum mood disorders. In addition, mothers who have synthetic oxytocin during labor are more likely to have epidurals, which also block the release of naturally occurring oxytocin during birth and therefore increases the risk of depression (Kendall-Tackett, Cong, & Hale, 2015).

Sometimes, mothers simply do not know why this is happening. And we may not need to. Determining the origin of the stress or trauma that triggered D-MER is not as important as recognizing that this system has been disrupted and taking steps to counter it.

Is D-MER Related to Dopamine?

Some researchers have attributed the phenomenon of D-MER to a decrease in the levels of dopamine, the substance that is released in the reward center in the brain to cause well-being (D-MER.org, n.d.). In our view, the evidence from hormonal research does not support that hypothesis. The possible involvement of dopamine is not consistent with the hormonal reaction that takes place during breastfeeding, nor with the symptoms the mothers describe. Of particular relevance is the rapidity of the symptoms, which suggests oxytocin as the culprit, rather than prolactin or dopamine, as it is released within minutes of breastfeeding: when the symptoms of D-MER occur.

Prolactin release is, in part, mediated by a decrease in the levels of dopamine in some nerves in the hypothalamus, which reach the prolactin-producing cells in the anterior pituitary. Prolactin is released slowly in response to suckling; the levels increase 10–20 minutes after feeding begins and then remain high for at least an hour. This delay of prolactin release is not consistent with mothers’ symptoms (Uvnas-Moberg, 2015), which occur almost immediately after the onset of suckling.

Since dopamine mediates prolactin, not oxytocin, it also seems unlikely that it is involved in the symptoms of D-MER. In addition, it’s unclear whether the activity of the dopamine neurons that control prolactin secretion in the anterior pituitary parallel the activity of the dopamine neurons in the reward center. These dopamine neurons may act independently of each other (Uvnas-Moberg, 2015).

Ruling out dopamine has implications for treatment. Medications that act as dopamine antagonists, such as Wellbutrin (bupropion), have been recommended to treat D-MER. However, since the treatment with this type of medication is based on the assumption that lowered dopamine levels cause D-MER, and as dopamine is not likely involved in D-MER, this medication is unlikely to be effective, as Bonnie describes.

Some mothers claim that bupropion helps, and we do not want to discount their experiences. However, this medication has never been used in a double-blind trial to treat D-MER, which is necessary to rule out the placebo effect (i.e., mothers believe that it will help, so it does). The placebo effect accounts for about a 30% reduction in depressive symptoms. For an antidepressant to prove efficacious, its efficacy rate needs to exceed that 30% (Khan & Brown, 2015; Sonawalla & Rosenbaum, 2002).

Promoting Safety

With D-MER, breastfeeding triggers the fight–flight response, suggesting that mothers do not feel safe. The primary strategy, then, is to help mothers with D-MER feel safe. In the early days, mothers need to be surrounded by people they trust. This may mean blocking some people’s access to the mother if they are not helpful—even if they are relatives or hospital staff. The goal is to turn off the hyperactive stress response.

Skin-to-Skin Contact and Massage

Skin-to-skin contact is another potent way to increase oxytocin and downregulate the stress response in both mother and baby. If newborn infants are put in skin-to-skin contact after birth, stress is reduced in both mother and baby. In the baby, pulse rate and cortisol levels go down, the skin temperature increases, which is linked to decreased sympathetic nervous activity. The babies are less afraid and more socially interactive with their mothers. Mothers also experience these antistress effects as reflected by lower cortisol, greater calm, and more interaction (Bigelow, Power, MacLellan-Peters, Alex, & McDonald, 2012; Handlin et al., 2009; Jonas et al., 2008). Birth is extremely stressful for both mother and baby. Skin-to-skin contact has a powerful antistress effect and decreases the stress of being born (Bystrova et al., 2003).

Increasing skin-to-skin contact may override the negative reaction mothers experience with D-MER. The reason we suggest this as a strategy is that skin-to-skin contact and massage have stronger links to the antistress (or parasympathetic) system than suckling and MER (Uvnas-Moberg, 2015). Skin contact could counter the negative effect associated with MER and possibly help re-pair MER with positive sensations.

There is only one caution. For some mothers, especially those with significant trauma histories, skin-to-skin contact can trigger negative reactions, so clinicians should be aware of this. However, for most mothers, it may help.

Mindfulness

Mindfulness is a technique adapted to Buddhism that has proven highly efficacious for a number of health conditions. It involves paying attention to breathing, and observing, but not engaging with thoughts. Mindfulness provides a break from the mental clutter that often occurs in all of our minds (Praeclarus Press Podcast, 2017; Sanford, 2018).

Mindfulness might also be helpful when mothers are flooded with the negative symptoms associated with D-MER. With mindfulness, mothers focus on their breathing, are in the present moment, and treat themselves with compassion. They remind themselves that the negative thoughts they are experiencing are thoughts, not facts. Patient education about the symptoms can also be helpful, so mothers know what these symptoms are and that they will go away soon. Aleesa described how changing her thinking about her symptoms made it easier for her to cope.

Mindfulness, particularly combined with cognitive-behavioral therapy, is a highly effective treatment for PTSD. PTSD also involves a hyperactive stress response, which mindfulness helps downregulate (Ruglass & Kendall-Tackett, 2015). Similarly, we believe that mindfulness gives mothers a way to cope with D-MER until the negative emotions subside. It also provides a powerful mechanism for downregulating the stress response.

Environmental Factors

A clean and orderly environment can be helpful in downregulating a mother’s stress response—have music the mother enjoys, with a comfortable place to sit, and nice things to look at. Warmth also triggers the oxytocin response (Uvnas-Moberg, 2015). Give the mother a hot pack around her shoulders, or suggest that she soak her feet in warm water. The goal is to use the mother’s environment to help her feel comfortable and safe.

Self-Care and Nutrition

In a case study of a mother of a 10-day-old infant with D-MER in The Breastfeeding Atlas (Wilson-Clay & Hoover, 2017), Wilson-Clay suggested that the mother add 4 oz of protein at each meal to help recover her strength and maintain blood sugar levels. The mother noted the following:

This case illustration is of interest because insulin, a hormone that lowers blood sugar levels, is also released by oxytocin and suckling (Uvnas-Moberg, 2015). In some women, breastfeeding may be linked to very high insulin levels, but this response can be modulated by diet, in particular by removing excessive amounts of carbohydrates.

Significantly, the mother also stopped her extra pumping and simply focused on breastfeeding, “instead of pushing my system to make loads of extra milk” (p. 141). That also eased her symptoms. The combination of self-care and protein seemed to help this mother’s symptoms improve.