Breastfeeding: Lifestyle and Breast Milk (cont.)

Sometimes a baby can be born with a condition called primary lactase deficiency or with galactosemia, in which they can't tolerate breast milk. This is because their bodies can't break down lactose, a sugar found in the milk of humans and animals. Symptoms include diarrhea and vomiting. Babies with severe galactosemia may have liver problems, malnutrition, or mental retardation. Babies with these conditions must be fed formula that comes from plants, such as soy milk or a special galactose-free formula.

Smoking, Drugs and Alcohol


Nursing mothers should not smoke or take drugs. Tobacco from cigarettes contains a drug called nicotine, which transfers to breast milk and may even affect the amount of milk you produce. The risk for sudden infant death syndrome (SIDS) becomes greater when a mother smokes or when the baby is around second-hand (or passive) smoke. Smoking and passive smoke may also increase respiratory and ear infections in babies. If you smoke and are breastfeeding, talk to your health care provider about what you can do to quit smoking. If you can't quit, breastfeeding still is best because the benefits of breast milk still outweigh the risks from nicotine.

Illegal Drugs

Some drugs, such as cocaine and PCP, can make the baby high. Other drugs, such as heroin and marijuana can cause irritability, poor sleeping patterns, tremors, and vomiting. Babies can become addicted to these drugs.


Alcohol does get to your baby through breast milk, and has been found to peak in its concentration about 30 to 60 minutes after drinking, or 60 to 90 minutes if it is taken with food. The effects of alcohol on the breastfeeding baby are directly related to the amount of alcohol a mother consumes. Moderate to heavy drinking (2 or more alcoholic drinks per day) can interfere with the let-down reflex and the milk-ejection reflex. It also can harm the baby's motor development and cause slow weight gain. For this reason, and for the general health of the mother, if alcohol is used, intake should be limited. If you know that you are going to have alcohol, such as some wine with dinner, you can pump your milk beforehand to give to your baby after you have had the alcohol. Then pump and discard the milk that is most affected by the drink(s).


Most medications have not been tested in nursing women. No one knows exactly how a given drug will affect a breastfed child. Most over-the-counter and prescription drugs, taken in moderation and only when needed, are thought to be safe. You should always check first with a health care provider before taking medicine. To reduce the baby's exposure, you can take the drug just after nursing or before the baby sleeps. Even mothers who must take daily medication for conditions such as epilepsy, diabetes, or high blood pressure may be able to breastfeed.

In general, when breastfeeding it is safe to take:

  • acetaminophen (like Tylenol)
  • antibiotics
  • epilepsy medications (although one, Primidone, should be taken with caution - talk with your health care provider about this drug)
  • most antihistamines
  • aspirin (should be used with caution)
  • moderate amounts of caffeine; remember there is caffeine in soda and candy bars
  • decongestants
  • ibuprofen (like Advil)
  • insulin
  • quinine
  • thyroid medicines
  • progestin-only birth control pills (the "mini-pill")

You can go to the American Academy of Pediatrics web site,, for a more detailed list of drugs and their effect on breast milk.

Medications that are not safe to take when breastfeeding:
Some drugs can be taken by a nursing mother if she stops breastfeeding for a few days or weeks. She can pump her milk and discard it during this time to keep up her supply. During this time, the baby can drink her previously frozen breast milk or formula. These drugs include radioactive drugs used for some diagnostic tests like Gallium-67, Copper 64, Indium 111, Iodine 123, Iodine125, Iodine-131, radioactive sodium, or Technetium-99m, antimetabolites, and a few cancer chemotherapy agents.

There are drugs that if new mothers have to take them, they need to choose between taking them or breastfeeding. Some of these drugs that should never be taken while breastfeeding include:

  • Bromocriptine (Parlodel) - a drug for Parkinson's disease, it also decreases a woman's milk supply.

  • Cyclophosphamide, Doxorubicin, and most chemotherapy drugs for cancer - these drugs kill cells in the mother's body and may harm the baby.

  • Ergotamine (for migraine headaches); Methotrexate (for arthritis); and Cyclosporine (for severe arthritis and psoriasis, aplastic anemia, Crohn's disease, kidney disease, and for after organ transplant surgery).

Drugs whose effects on nursing infants is not known but may be cause for concern include:

The above information is in part, information provided by the National National Women's Health Center (

Last Editorial Review: 1/13/2004

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