Callaghan O'Hare / Reuters

The number seems small, but gets larger and larger as you contemplate it: 6 percent. That is the estimated share of breastfeeding mothers who exclusively pump and bottle their milk for their infants, never directly nursing. It is a number that was functionally zero less than a generation ago. And it is a subset of a much larger figure, the 85 percent of breastfeeding mothers who use a pump at least some of the time. This is no less than a “quiet revolution” in human nutrition, as researchers put it.

Women have become, in Jill Lepore’s evocative phrasing, their own wet nurses. When pumping, their breast milk becomes a commodity; they become producers and their infants consumers, the dyadic experience of breastfeeding unnecessary or secondary. Maybe this is a good thing, if pumping helps babies receive more breast milk, or if it enables mother and child to sustain a desired, direct breastfeeding relationship for longer. Maybe pumping helps women have it all—a full-time career and a breastfed baby. But there’s just one hitch, or two, or three. This “quiet revolution” is built on a foundation of surprisingly scant research and social support.

“We have an information gap on how many women are exclusively pumping, and over what period of time,” says Kathleen Rasmussen, a professor of maternal and child nutrition at Cornell. “We have an information gap about who’s actually feeding the baby the pumped milk. We have an information gap related to how clean the pumps are.” She went on: We have questions about best practices for pumping, about pumping and stress. The questions are more profound, too. In what ways does it all matter? “Does it matter to the woman?” she asks. “Does it matter to the baby’s health? Does it matter to the baby’s development? We really can’t say.”

This quiet revolution has economic, technological, and political roots. Many women entering the American workforce in the mid-20th century formula-fed their children, with breastfeeding rates reaching a nadir in the early 1970s. Backlash against formula manufacturers, social interest in more natural kinds of parenting, and public policy helped push that rate back up. But women who worked outside of the home still had to figure out how to feed their babies. Only in the early 1990s did efficient, electric pumps come on the market, making pumping a viable option.

Policy has doubled down on it. The U.S. government does not require employers to provide new parents with paid leave. But it does urge mothers to breastfeed, and in the past decade has pushed for them to pump, too. The Affordable Care Act of 2010 mandated that insurers cover a pump and visits to lactation specialists, and required employers to give mothers time and space to express their milk. The Internal Revenue Service declared lactation equipment tax deductible in 2011. As a result, the market for pump equipment is booming.

But while pumping might support direct nursing, it is not equivalent to direct nursing, researchers have found. The microbiome of expressed breast milk is different, for one. “Indirect breastfeeding” is associated with a greater prevalence of pathogens, which “could pose a risk of respiratory infection in the infant, potentially explaining why infants fed pumped milk are at increased risk for pediatric asthma,” according to Shirin Moossavi of the University of Manitoba. Plus, breast milk degrades when it is cooled, as it often is when stored for bottle-feeding. There is also the risk of contamination, given that dangerous bacteria flourish on pump parts.

Researchers also sense that the experience of breastfeeding—the eye-gazing, the cuddling—is a big part of the benefit of breastfeeding for the baby, and a big part of the joy of breastfeeding for the mother. How does bottle-feeding change the equation? How does the experience of needing to pump as often as 10 times a day change things? It is unclear.

Many mothers find themselves in the dark, too. I pumped for my son, who was born prematurely. Awake to pump in the middle of the night, I wondered when adding more pumping sessions would result in diminishing returns to my total supply: Going from three sessions to four must have a bigger effect than going from nine to ten. But by how much? Does time on the pump matter more than the total number of sessions? How much does it help to space the sessions out evenly around the clock? As far as I could tell, there were no good answers to those questions. Fiona Jardine, a lactation expert and doctoral candidate at the University of Maryland, confirmed my suspicion: “There’s a dearth of research on lactation in general,” she said.  

Nor are there many good lay resources for pumping parents. The handful of other exclusively or primarily pumping mothers I know were mostly making it up as they went along, using Facebook as a central resource. “The reality is that there are very few medical professionals [who are] well-versed in exclusive pumping,” Amanda Glenn, one of the few experts out there, told me in an email. “There just aren’t a lot of ways for new moms to get accurate and helpful advice from someone who understands what they are going through and what their reality is.”

That reality is a tough one, as anyone who has ever used a breast pump will tell you. Exclusive pumpers describe themselves as “frustrated,” “discouraged,” “challenged,” and “burdened,” Jardine has found, words that might just as readily apply to part-time pumpers, or women who need to pump at work.

Part of the problem is that the technology, though far more effective and efficient than it used to be, still leaves something to be desired. Using a pump means assembling a half-dozen fiddly plastic parts, putting on a special bra, and remaining strapped to a loud and uncomfortable machine for 15 or 20 minutes. When you’re done pumping, you’re not actually done—you have to disassemble the parts and wash them, sanitizing them occasionally too. Some new hands-free models promise to let women pump while grocery shopping, driving, or even just walking around in their own home. But they are expensive and less effective, many mothers find.

No matter how good the technology, it remains difficult to pump anywhere but home. Many workplaces now provide a clean, private pumping station for new parents. (The Atlantic is one of them; I pump in a shared room with a sink, a comfortable chair, and refrigerators.) But this is not true for all workplaces, or even close to all, hence the stories of women pumping in dirty bathrooms, in closets, in their cars. Surveys indicate that women who pump at work feel stigmatized. And outside of workplaces, there is virtually no infrastructure available to pumping mothers.

Moreover, time with the baby gets supplanted by time with the pump, leaving many women stressed out and exhausted—something that may have an effect on the quantity of milk produced, as well as the mother’s health and the overall stress level of the family.

For many pumping women, this is all worth it. They want to sustain their ability to nurse, or want to provide their children with breast milk rather than formula. But however they pump, for whatever reason, they do it in a vacuum: with a thin body of knowledge and little social support. Alas, it sucks.

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