All I find are very unusual/rare

Why some mothers can't breastfeed Nearly every mother and baby can breastfeed. However, there are rare instances when mothers or babies with specific medical conditions or mothers needing certain diagnostic tests are counseled not to breastfeed or to stop breastfeeding for a short time. The Centers for Disease Control and Prevention (CDC) publishes a list of medical conditions that preclude breastfeeding. This list is updated periodically, so women along with their health care providers can decide if the benefits of breastfeeding outweigh the risks.

Here are conditions that may preclude breastfeeding:

1. Babies with Galactosemia

Galactosemia is a rare genetic disease. Babies with galactosemia are unable to digest galactose, a sugar found in breast milk, and must be fed galactose-free formula. Knowing that early diagnosis leads to early treatment, babies are screened for galactosemia and other metabolic diseases at birth. Although galactosemia is a lifelong condition, it is easily managed with a galactose-free diet.

2. Babies with PKU

Phenylketonuria (PKU) is a metabolic disease similar to galactosemia. Babies with PKU cannot digest the amino acid, phenylalanine, and must be fed phenylalanine-free formula. Unlike babies with galactosemia who must be formula-fed, babies with certain types of PKU can partially breastfeed. However, the amount of phenylalanine in the baby’s blood must be periodically measured to ensure that it is below a certain level.

3. Active, untreated Tuberculosis in mothers

Tuberculosis (TB) is a disease caused by bacteria. It usually infects the lungs (pulmonary tuberculosis), but can infect other body parts as well, including the breast. When a mother with pulmonary tuberculosis sneezes or coughs, the bacteria can spread to her baby. Keeping babies disease free is a top priority. In the past, mothers with active, untreated TB were routinely separated from their babies until the mother was no longer contagious (about two weeks after the start of treatment). Today, every effort is made to keep mothers and babies together while being treated. But given the many different scenarios, each case must be evaluated individually. If both mother and baby are infected, they can be isolated together and continue to breastfeed while both are treated. If only the mother is infected, the mother and baby may be separated until treatment is started or longer (up to two weeks after the start of treatment) if the mother is highly contagious. The bacteria that cause TB do not transfer into breast milk, so a mother with active TB who is separated from her baby can express her milk and have it fed to her baby until she is able to resume breastfeeding.

4. HIV-positive mothers

HIV-positive mothers living in developed countries are advised not to breastfeed. In contrast, those living in developing countries where sanitation, clean water, and adequate supplies of breast milk substitutes are unavailable or limited are urged to breastfeed exclusively, since the risk of babies dying from infectious disease is greater than the risk of HIV infection. The use of antiretroviral drugs has reduced the risk of mother-to-child HIV transmission during pregnancy and while breastfeeding. Nonetheless, HIV-positive mothers living in developed countries are urged to talk with their health care provider about the benefits and the risks before deciding to breastfeed. (To learn more about HIV and breastfeeding, read this.)

5. Mothers with HTLV Type 1 or 2 infection

Human T-cell leukemia virus type 1 (HTLV-1) is spread through sexual contact, bodily fluids, blood transfusions, breastfeeding, and from mother to fetus during pregnancy. Many people infected with HTLV-1 develop T-cell leukemia and lymphoma as adults. Studies comparing transmission rates based on infant feeding type show that 30 percent of exclusively breastfeeding babies born to mothers infected with HTLV-1 become infected, as opposed to only 10 percent of mixed-feeding infants. No formula-fed infants developed the disease. Because only 1–5 percent of those infected with HTLV-1 develop leukemia, mothers with this disease are urged to discuss infant feeding options with their health care providers. Similar to HIV recommendations, HTLV-infected mothers who live in developing countries, where the risk of not breastfeeding may be greater than the risk of breastfeeding with the disease, are often urged to breastfeed their infants.

6. Illegal drug use in mothers

The risks of breastfeeding by mothers using illegal drugs are twofold: whether the drugs will negatively affect the infant, and whether the drugs will impair the mother’s ability to adequately care for her baby. Drugs such as cocaine, LSD (and other hallucinogenic drugs), heroin, marijuana, and amphetamines (taken in larger than prescribed doses) are all contraindicated while breastfeeding because of the effects on the baby’s developing nervous system. Mothers participating in methadone treatment programs can breastfeed, but their babies should be carefully observed for adverse effects. The Academy of Breastfeeding Medicine’s protocol on Breastfeeding and the Drug-Dependent Woman lists criteria for when breastfeeding should or should not be supported.

7. Mothers receiving chemotherapy

Chemotherapy drugs are designed to kill rapidly producing cells such as cancer cells. Since babies are one big bundle of rapidly producing cells, chemotherapy drugs are not compatible with breastfeeding. The length of time these drugs remain in the mother’s system (and her milk) varies from drug to drug. Mothers who would like to resume breastfeeding after their cancer treatment ends, should talk with their cancer doctor as well as their baby’s doctor to ensure that it is safe to breastfeed.

8. Mothers receiving radiologic tests

Only a small amount (less than 1 percent) of the contrast material used for radiologic tests passes into a mother’s milk. The baby absorbs even less, so there is no need to interrupt breastfeeding. While contrast agents used for testing are considered safe, those used for treatment purposes, such as radioactive iodine (RAI), can be extremely toxic. Because RAI concentrates in breast milk, mothers receiving RAI are cautioned to wean several weeks prior to treatment to limit breast exposure. Exposing the breasts to RAI increases a mother’s risk for breast cancer. X-ray treatment, even for breast cancer, is not considered a contraindication to breastfeeding. Mothers can continue to breastfeed on the non-radiated breast, as long as they are not receiving chemotherapy. Because the safety of radiologic tests and treatments varies with the contrast agent used, it’s essential that mothers talk with their health care provider as well as their baby’s health care provider before making a decision about breastfeeding.

The importance of human milk for human babies is illustrated by the fact that there are very few conditions that preclude breastfeeding. Babies breastfed exclusively for 6 months are healthier, not just in infancy, but for many years to come compared to formula-fed babies or babies fed a combination of formula and breast milk. Fortunately the breastfeeding challenges many mothers experience in the early weeks, such as nipple pain and breast engorgement, are short-lived and easily managed. Mothers who are unable to breastfeed for any reason can still bond with their babies by holding them skin-to-skin during feedings.