Earlier this year, my colleague Katie Allison Granju wrote a Strollerderby post about a little-known condition that affects some nursing mothers: dysphoric milk ejection reflex, or D-MER. Moms with D-MER are overcome by a sudden wave of emotional pain – dread, sadness, hopelessness, stomach churning – just as breast milk is released. The feelings fade after a few minutes, only to reappear with the next milk letdown.

Comments on Granju’s post poured in, as they have on the website D-MER.org, which was founded to raise awareness of the phenomenon:

I didn’t know there was anyone else out there like me. Every time my son would latch on, I would feel such despair – as if the world were about to end, and me with it. It was very deep and very black.

I was always so confused when I heard/read other mothers describing a feeling of happiness, calm and elation during let-down b/c I have always felt the opposite – sadness, hopelessness, depression. And then it passes quickly. Thanks for giving a name to what I’ve experienced!

WOW. I thought I was crazy! I got that sharp “homesickness” pang when I first used a pump to stimulate labor. It was bizarre and continued after my daughter was born.

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Alia Macrina Heise, a lactation counselor and postpartum doula, was the first to describe D-MER and give it a name in 2008. Heise had nursed her first two children smoothly, but with her third she was overwhelmed by an inexplicable feeling of worthlessness and hopelessness in the pit of her stomach each time her baby fed. Looking for an explanation, she started searching online and cautiously chiming in on threads started by moms with the same experience. Getting the sense that what she was going through was far from unique, she began consulting other lactation specialists and ultimately started D-MER.org.

The biological theory of D-MER, says Heise, has to do with the chemistry of nursing: the neurotransmitter dopamine inhibits the hormone prolactin, needed for milk production. Therefore, levels of dopamine (linked to positive mood) may drop to allow for breast milk production. For some moms, a chemical glitch could cause a steeper drop, canceling out the usual warm, cozy, oxytocin-induced feelings and tripping unpleasant emotions and physical sensations at the time of milk letdown.

When I heard about this mysterious nursing affliction, my inner scientist was skeptical. Before I could take it seriously, I wanted to see evidence – a long results list on an academic research database, textbook references, perhaps a brain scan study? Instead, the medical literature makes little mention of anything resembling D-MER.

Still, I couldn’t ignore how powerfully so many moms have responded to Heise’s description of the condition. And the way they describe their feelings is uncannily similar: sinking, hopeless, fearful, guilty, empty, and then it passes – over and over moms chimed in.

A quick look at the science of lactation and brain chemistry confirms that the D-MER theory has biological footing. Merrill Sparago, a Los Angeles psychiatrist who specializes in perinatal mood disorders tells me he hasn’t seen women with D-MER, but he is open to the possibility that it could exist, given that hormones of breastfeeding and mood are indeed tied. And the specific pathway could make sense: Because dopamine inhibits the release of prolactin, he noted, “medications that block dopamine can cause an increased secretion of prolactin and lead to gynecomastia (enlarged breasts in men).” The idea behind D-MER – dopamine levels plummeting before milk production – could theoretically be part of a feedback loop.

And in fact two well-respected breastfeeding textbooks have included D-MER in their latest editions. Lawrence and Lawrence’s Breastfeeding: A Guide for the Medical Professional, whose 7th edition came out last year, has a section that describes D-MER and notes, “clinicians need to be aware of this phenomenon.” And La Leche League’s 8th edition of The Womanly Art of Breastfeeding, also published last year, calls D-MER “a little-recognized ‘glitch’ that most affected women never talk about because they don’t want to be treated for a depression that they suspect they don’t have.”

That last point is an important one, and when I contacted Heise to tell me more about D-MER, her first point was that it is not related to postpartum depression, and it’s not a breastfeeding aversion. D-MER is a specific, abrupt physiological reflex around milk release. Moms with D-MER feel fine throughout the rest of the day; it’s only during milk ejection that the world becomes momentarily bleak.

I asked Heise a nagging question I’ve had since I read about D-MER and saw how many moms identify: Do all these moms really have the condition, or do some just relate to the emotional struggle around breastfeeding and feel comfort in finding a label? Heise wrote back to me that this does happen, but she’s more concerned with what a mom does with the label as a result: “We have seen our fair share of misunderstandings,” she said. “But D-MER has a pretty clear ‘M.O.’ – if you’ve experienced it, you recognize it very quickly once finding the website. We have, unfortunately, seen some mothers simply decide they have D-MER without careful investigation, often in order to give them a reason to wean.”

Heise’s objective is not to offer mothers a breastfeeding “out.” She continued to nurse her third baby through D-MER, bolstered by her sense of it as a physiological symptom that could be explained and was temporary – and she hopes to help other nursing moms view it similarly. “D-MER.org was not created to give mothers an excuse to stop, but to empower mothers to press on,” she says. And she has found that many moms who felt frustrated and confused about their feelings are able to continue once they read that there’s a biological explanation for what’s happening to them. Instead of questioning why they feel so bad, they learn to recognize and expect it – “okay, here it is” – and know it will pass.

Heise also recommends that women track the triggers, like stress or dehydration, that make the emotional let-down worse. For severe cases in which moms contemplate weaning (when they otherwise would have wanted to continue), Heise said she knows of doctors prescribing medications that increase dopamine levels. On her website she suggests that moms with D-MER aren’t as vulnerable to the drop in prolactin and therefore milk supply that would otherwise accompany a “dopamine agonist” – a drug that ups dopamine – although this isn’t medically substantiated.

Thinking back over my time nursing, I have to admit that some of the D-MER language resonates with me. No doubt a cloud of anxiety and weepiness stayed with me for a few weeks after my son’s birth (wholly unrelated to breastfeeding – more a case of the regular old baby blues). But a momentary, aching hollowness somewhere in the pit of my stomach – that strange sense of dread and even homesickness that moms who believe they have D-MER describe – feels vaguely familiar to me.

I come away from my research on D-MER pretty comfortable with it being a real, physical experience (and what a tough one to have on top of the normal emotional turbulence that accompanies having a newborn). What I still have a healthy dose of skepticism about – and Sparago agrees here – is whether we can know its precise mix of hormones and neurotransmitters. The physiology of mood and emotion is so complicated it rarely works in a simple equation. When I raised this question to Heise, she agreed that the biology isn’t conclusive, but she said the rapid onset simultaneous to milk letdown makes her confident.

She told me, “The lactation community and the medical professionals within it have been overwhelmingly accepting” of D-MER as a condition. Heise and colleagues have conducted surveys, and their findings have now been submitted, and preliminarily accepted, for publication. Those events may bring formal research interest to what has so far been a grassroots effort.

If that happens it’s unclear how the story of D-MER will unfold – how many moms will be shown to truly have it, whether an underlying physiology will be revealed and, if so, how it actually works – but Heise, her colleagues in the lactation world and a huge number of new moms are surely going to be paying close attention.