1) Herpes simplex
The herpes simplex virus can cause blisters; the liquid in the blisters contains the virus. Babies can become infected by contact with the blisters when they breastfeed on an infected nipple and areola.
Newborns and young babies who develop herpes infections (neonatal herpes) can suffer major effects and even death. This is most common in the first month after delivery.
If a mother has active herpes simplex blisters on her nipples and areolas and is breastfeeding a baby under six months of age, she should not breastfeed until the blisters have opened and dried up. This is usually within 10 days. While the milk is safe, expressing will likely allow the virus to contaminate it. Mothers need to express and throw out the milk until the baby can resume breastfeeding.
2) Herpes zoster (chicken pox and shingles)
Herpes zoster is the virus that causes chicken pox. Mothers who develop a chicken pox infection between five days before and two days after birth of the baby should be separated from their babies. Expressed milk can be given to the baby. If it develops before or after that time, mothers should continue to breastfeed.
After a person recovers from chicken pox, the virus can stay asleep in nerves. Occasionally, it is re-activated and comes out of a nerve, creating a line of blisters and pain along the path of the nerve, around one side of the face or body. This is called shingles. The blisters of both chicken pox and shingles contain Herpes zoster virus particles.
The blisters of shingles should not be in direct contact with the baby. The risk to the baby is reduced if the baby has been vaccinated against chicken pox. Contact is safe once the blisters have opened and dried.
3) Hepatitis B and C and bleeding nipples
There is a low risk of a mother transmitting hepatitis B to her baby if the baby is immunized within 12 hours after birth (CDC 2015).
Hepatitis C is not transmitted through breastfeeding but may be transmitted through blood.
Some authorities recommend that a mother who has bleeding nipple damage and hepatitis B or C infection should avoid breastfeeding and express and throw out her milk until her nipples have stopped bleeding but there is not enough research to make this a firm recommendation (CDC 2018; CPS 2008; Cottrell 2013).
Cytomegalovirus (CMV) is a common infection. Blood tests are available to diagnose it.
Guidelines on whether to give milk of CMV-infected mothers to very premature babies vary around the world (Schleiss 2019). CMV can be eliminated from breast milk by heat treatment (pasteurization) (Maschmann 2019). However this also reduces some of the benefits of breast milk.
5) Breast abscesses
Babies should not breastfeed if they are in direct contact with pus or infected tissue from a breast abscess.
The tuberculosis bacterium is spread through droplets in the breath. If a mother has infectious tuberculosis, she needs to avoid being with her baby until testing shows she is no longer contagious, usually two weeks after starting medication. The baby can drink her expressed milk.
Tuberculosis rarely infects the breast. Breastfeeding from a breast infected with tuberculosis should be delayed until treatment has killed all the bacteria.
Brucellosis is an infectious disease caused by bacteria. Various animals, including sheep, cows, goats, pigs, elk, moose, wild hogs, and dogs, may be infected with brucellosis. Humans become infected when they eat undercooked meat or unpasteurized or raw dairy products, breathe in the bacteria, or the bacteria is in contact with wounds or wet surfaces of the body.
Brucellosis can cause a range of problems including:
- Joint infections
- Swelling of the heart, liver, or spleen
- Nervous system problems
Mothers with untreated brucellosis should not breastfeed, since the bacteria can be transmitted to the baby. Breastfeeding can resume after treatment (Arroyo Carrera 2006; Dadar 2021).
Botulism is a rare and possibly deadly disease caused by a toxin released by the bacterium Clostridium botulinum. As babies have a weakened immune system, they are more likely to become infected than older children. These bacteria can be found in honey and is why it should not be given to babies under one year of age.
A mother with botulism should not breastfeed or feed breast milk to her baby until she is well as the toxin may be transferred through breast milk.
9) Mothers who have acute poisoning with chemicals or metals
Breast milk has been found to contain environmental contaminants such as persistent organic pollutants, pesticides, dioxins, and heavy metals. However, the levels are generally low and the benefits of breastfeeding for mother and baby nearly always outweigh the risks.
Mothers with acute poisoning from chemicals such as lead, may need to temporarily express and throw out their milk until they are treated and the source of the chemical is identified.