What is chestfeeding? How it relates to trans parents and what the CDC says

The Centers for Disease Control and Prevention has frequently faced political criticism. But a new wave hit in early July over breastfeeding — or "chestfeeding," as the agency described it on a website.

"In case you missed it, transgender extremists running @CDC push abuse of newborns through ‘chestfeeding,’" conservative activist Tom Fitton tweeted July 9. 

"CDC says gender confused men can ‘chestfeed’ with a medical excretion," another user tweeted July 11 in all caps. 

Critics focused on a CDC webpage that addresses frequently asked questions about breast surgery. One question asked, "Can transgender parents who have had breast surgery breastfeed or chestfeed their infants?" 

Yes, replied the CDC, noting that the term "chestfeed" is "used by some transgender and non-binary parents." 

Several conservative news outlets also began covering the story. U.S. Sen. Roger Marshall, R-Kan., a former OB-GYN, condemned the CDC’s language and expressed concern over medications that may be taken to induce lactation.

The language on the CDC website wasn’t new; it has remained unchanged on the CDC page since 2018, according to the Internet Archive. But we wanted to look at chestfeeding and some of the new attention around it. Some of the claims misrepresented what chestfeeding is, how the term is used and raised fears over medications involved in induced lactation. 

Research is limited, but here is what we know. 

Chestfeeding is a gender-neutral term used by some transgender and nonbinary dads when nursing their newborns.

Most people who are assigned female at birth, including people who identify as men or as nonbinary, can get pregnant and have children. Trans men may have to stop taking testosterone to conceive, and are instructed to stay off hormones during pregnancy.

These parents, who were pregnant and had a baby, may also want to nurse their newborn infants but prefer a word other than "breastfeeding." The term may cause gender dysphoria, which can exacerbate mental health challenges such as anxiety and depression. Additionally, trans men who have had "top surgery" may not have breasts.

Transgender parents who are assigned female at birth will have gone through the hormonal roller coaster of pregnancy, which includes the development of mammary glands and the increase of milk production. After birth, some parents may opt to suppress lactation and feed with formula instead.  

But trans dads who want to nurse may face some unique challenges, as outlined in protocol from the Academy of Breastfeeding Medicine. Chest binding, which is common among trans men to reduce the appearance of breasts, can result in compression atrophy of breast tissue; those who have had breast tissue surgically removed also risk having a reduced ability or inability to lactate. 

The term "chestfeeding" is typically used by transgender men and people who feel the traditional feminine terminology doesn’t match with their experience or bodies. But in the backlash toward the CDC, some headlines have associated the term with transgender women (people who are assigned male at birth and identify as women).

"CDC endorses ‘chestfeeding’ for biological males, triggering criticism from medical experts," read a headline from Children’s Health Defense, an activist group started by Robert F. Kennedy Jr., now a Democratic presidential candidate.

The term is not typically used this way, but let’s address the question: Can transgender women  lactate? The answer is yes, but it is rare.

Both men and women are born with mammary glands and nipples that can produce milk. When females hit puberty, the estrogen kicks into high gear, and the mammary glands develop further into breasts.

With pregnancy, hormones are released that further the development of the mammary glands, and cause breasts to begin producing milk, said Dr. Casey Rosen-Carole, chief of the Division of Breastfeeding & Lactation Medicine at the University of Rochester School of Medicine.

The development of mammary glands and breast tissue can occur in trans women who take estrogen and progesterone as a part of hormone replacement therapy. Rosen-Carole cited research that mammary tissue in transgender women who have taken hormones can be "as well organized for milk production as someone who was assigned female at birth."

If mammary tissue is developed, lactation can be "induced" by mimicking the hormones produced in pregnancy. Induced lactation is not new and not exclusive to transgender people. Adoptive parents and nonbirthing mothers have been doing it for much of human history — think wet nurses and others who breastfed babies who were not their own. However, people who induce lactation are prone to low milk supply, so they may have to supplement with formula.

Protocols for inducing lactation have been medically documented for more than two decades. Some involve medication; others use herbs or simply feeding at the breast. There are only two case reports in the scientific literature of induced lactation in transgender women, but Rosen-Carole said there have been more successful cases that have not been documented. She has had three patients who have induced lactation with varying success. 

Some online were particularly concerned that the milk produced by transgender women was not real breast milk, referring to it as "untested frankenmilk" or "chemically laden secretions."

When the breast milk produced by transgender women has been studied, "milk is nutritionally adequate and co-equal to milk produced by cis-gender women based on macronutrient analysis," Rosen-Carole said, referring to a 2023 study published in the peer-reviewed Journal of Human Lactation.

Marshall, the Kansas senator, said he was concerned about the prolactin-promoting medications used to induce lactation and their effect on infants: "The CDC is encouraging these individuals to use Domperidone, a risky drug not legally approved or sold in the U.S." 

A CDC spokesperson said in an email to PolitiFact that the "CDC did not endorse using drugs to induce lactation." And there is no mention of any specific drugs on the breastfeeding information page. The CDC notes that families may need help from healthcare providers with medication that can be used to induce lactation. 

There are two medications commonly prescribed around the world to promote lactation: domperidone and metoclopramide, known as Reglan. These medications are typically used to treat nausea and vomiting and other gastrointestinal issues. 

Domperidone is not FDA-approved and is not prescribed in the United States. It has been shown in research to be the most effective at inducing lactation, Rosen-Carole said. The FDA has warned against its use after some published reports showed cardiac complications when taking the drug. 

Metoclopramide is FDA-approved, but has shown mixed success at promoting and inducing lactation and can have side effects such as fatigue, dizziness, depression and anxiety. It’s typically prescribed for periods of two to four weeks. Experts and online resources say metoclopramide has not been tied to health complications in infants. Both drugs are more dangerous for people with congenital heart conditions.  

Generally, research on induced lactation is scant even for cisgender women, said Rosen-Carole, and it is especially sparse for the trans population. There are only a few medications that are not recommended while breastfeeding, such as chemotherapy drugs, oral retinoids and drugs that may be abused. The CDC’s website says that "although many medications do pass into breast milk, most have little or no effect on milk supply or on an infant’s well-being."

Still, parents should consult with their doctors about any medications they may be taking while lactating. And, as Rosen-Carole suggested, they should lean on their confidants, because nursing a newborn is hard. 

"People are less likely to reach their (breastfeeding) goals if they don't have social support, if they have a history of trauma, if they're low income, or if they have other medical complications," Rosen-Carole said. "We know that the LGBTQIA community is at higher risk of all those things."