Breastfeeding and Vaccines

Maternal Vaccines

Are Maternal Vaccines Safe While Breastfeeding?

Mothers often wonder if breastfeeding is compatible with medications, how drugs affect breast milk, and how medications in milk affect a baby.  Vaccines are no different; before getting a vaccine most breastfeeding mothers want to ensure it will not negatively impact their milk or baby.  While many breastfeeding mothers will never be faced with needing a vaccine while breastfeeding, others (due to international travel, endemic illness, etc.) will need one or more.

The CDC states:

“Neither inactivated nor live vaccines administered to a lactating woman affect the safety of breast-feeding for mothers or infants.  Breast-feeding does not adversely affect immunization and is not a contraindication for any vaccine. . . . Although live vaccines multiply within the mother’s body, the majority have not been demonstrated to be excreted in human milk.  Although rubella vaccine virus might be excreted in human milk, the virus usually does not infect the infant.  If infection does occur, it is well-tolerated because the viruses are attenuated.  Inactivated, recombinant, subunit, polysaccharide, conjugate vaccines and toxoids pose no risk for mothers who are breast-feeding or for their infants.” 1

Vaccines WITH Precautions for Breastfeeding

  • Smallpox – contraindicated while breastfeeding

Vaccines Without Breastfeeding Precautions

  • Immune globulins, including Rh immune globulin (RhoGAM)
  • Diphtheria
  • Tetanus
  • Hepatitis A – CDC states that no safety research is available. While it is most likely safe, consider administering the immune globulin instead of the vaccine.
  • Hepatitis B
  • Influenza (inactivated whole virus or subunit)
  • Japanese Encephalitis – No data available regarding its safety during breastfeeding
  • Measles
  • Meningococcal Meningitis
  • Mumps
  • Pneumococcal – No data available regarding its safety during breastfeeding though it is unlikely to cause any concern in breastfed baby.
  • Polio, inactivated
  • Rabies – No data available regarding its safety during breastfeeding though it is commonly given to breastfeeding mothers without observed problems in baby.
  • Rubella
  • Tuberculosis (BCG) – No data available regarding its safety while breastfeeding.
  • Typhoid (Polysaccharide & Live bacterial) – No data available regarding its safety while breastfeeding, although CDC states it should be given in breastfeeding mothers when risk of exposure is high
  • Varicella
  • Yellow fever – Avoid administering to breastfeeding mothers unless travel to endemic areas is unavoidable. 2

What’s the Bottom Line?

While it is always best to not have to take any type of drug, medication, and/or vaccine while breastfeeding, all vaccines are considered safe if necessary with the exception of Smallpox.  There are many well-documented health consequences associated with formula, even for a short duration.  Therefore, when a vaccine is necessary in a breastfeeding mother it should not be a cause of breastfeeding concern or reason for supplementation and/or early weaning.

You may also be interested in reading about infant vaccines and breastfeeding.

Medications and Breast Milk

Medications and Breast MilkIntroduction

Most breastfeeding mothers will use some sort of medication while breastfeeding whether it is prescribed from a doctor or herbal in nature.  Many doctors will suggest a mother wean when taking a drug.  However, in actual fact, this is almost always not necessary.  Though most everything which a mother ingests, including medications, will enter her milk, the amount is usually small and the impact on her baby minimal.

How does a drug pass into breast milk?

There are several avenues (passive diffusion, lipid solubility, molecular weight, ion trapping, protein binding, and/or cellular transport system) by which a drug may be able to pass into breast milk.

Passive Diffusion

The most common is passive diffusion – which means that the concentration of a drug in maternal plasma is the same as that in breast milk.  Alcohol is a prime example.  As a mother’s blood plasma levels increase, so does the amount in her milk.  As her levels decrease, the quantity in her milk does as well.  This is why “pumping and dumping” breast milk is not effective to remove alcohol.  Knowing that most drugs pass into breast milk by passive diffusion is immensely helpful in choosing a medication.  Drugs with a short half-life (rather than “long-lasting”) will clear from breast milk quicker.  In fact, many times it is possible to time feedings so that the baby will nurse when levels of a drug in breast milk are already very low for example, right before taking a dose.

Lipid Solubility

The lipid solubility of the medication is another means by which it may transfer to breast milk.  Breast milk has more lipids (fat) than plasma. Therefore, the more lipid soluble a drug, the more likely it is to be found in breast milk.  In fact, a highly lipid soluble drug may have higher concentrations in breast milk than maternal plasma. 1

Molecular Weight

A drug’s molecular weight can be a factor impacting transfer into breast milk.  Medications with a smaller weight (300 daltons or less) can pass into milk more readily that those with weights exceeding 500-800 daltons.  Thus, drugs with high molecular weights (such as insulin) rarely enter breast milk. 2

Ion Trapping

While blood plasma maintains a pH of 7.4, breast milk is slightly more acidic with a pH of 7.2.  A highly alkaline drug may change its ionic state in breast milk and then be unable to pass back out to maternal serum. Therefore it is best to select medications with a lower pKa – ie. drugs that are more acidic. 3

Protein Binding

The ability of a medication to bind to protein (albumin) in the mother’s plasma is yet another factor.  Only the portion of a drug that is unbound can transfer into breast milk.  Ibuprofen is an example of a drug that is highly bound; therefore, little transfers to breast milk. 4

Cellular Transport System

Finally, there are few drugs that seem to have their own cellular pumping system.  Some medications are transported in, and others transported out.  Iodine (especially radioactive) is the most relevant to breastfeeding as this drug is actively pumped into breast milk.  5

Is it true that there are greater concentrations of a drug in breast milk during the first few days following birth?

Yes, this is typically the case.  However, it does not mean that your baby is getting greater doses of the medication through your milk.  The reason for greater drug transfer during the first few days postpartum is due to hormones surrounding lactation.  But since a baby’s total colostrum/milk intake is small, the total amount of drug he receives is still usually negligible.

What should I consider about taking a medication while breastfeeding?

Though any medication has the potential to enter breast milk, it is almost always in small amounts that are not considered harmful to your baby.  Formula has known risks associated with it.  Breast milk is a living substance that is perfectly suited for your baby each and every day.  It is resilient enough to withstand the times a mother has a need for medication and still make milk of excellent quality.  In fact, typically when a drug does enter breast milk, it is in a dose much lower than if the baby were prescribed the medication outright!  So, here are a few things to consider about taking a medication while breastfeeding:

  • Can I delay treatment?
  • Is there an alternative medication that is still effective and would be safer for my baby than what is prescribed?
  • Can I time feeds around the medication so that my baby gets less – ie. nurse then take the medication; not taking a “long-lasting” drug; etc.
  • What is the Relative Infant Dose (RID)?  If it is less than 10% most drugs are considered safe. The RID for most drugs is less than 1%! 6
  • Talk with your doctor about choosing medications that have high protein binding, high molecular weight, poor penetration to central nervous system, short half-life and low oral bioavailability.
  • Select drugs that are commonly considered safe to use with pediatric patients.
  • Watch your baby for any side effects to see how medications affect your baby.

Caffeine and Breastfeeding

Is it Safe to have Caffeine while Breastfeeding?

Breastfeeding and CaffeineYes, it is generally considered safe to consume caffeine while breastfeeding.  Though all babies are different and some may be more sensitive to the small amounts of caffeine that pass through breast milk, caffeine and breastfeeding are not contraindicated.

How Much Caffeine Passes into Breast Milk?

As a general rule, only about 1% of the maternal dose of any drug a nursing mother takes passes into her milk. But, most drugs are metabolized at a much slower rate in babies than in adults.  Caffeine is no exception.  Approximately 1% – 1.5% of the maternal dose is passed to a baby via breast milk.1 The half-life of caffeine is 97.5 hours in newborns, 14 hours in 3-5 month olds, 2.6 hours in 6+ month olds, and 5 hours in an adult.2  It takes 5 half lives to completely clear a drug from the system.  If you multiply the first-half life times five you will have an idea how long it takes to clear. So while very little caffeine that is ingested by a mother actually transfers to her baby, it can quickly accumulate.  It takes a newborn 487 hours (97.5 x 5) to completely clear caffeine from his system.  Though only a small amount may enter each day, it can quickly build up with such a long half-life. (Further information about drugs and breast milk can be found here.)

How is caffeine intake measured and what is too much?

Caffeine is measured in milligrams.  Peak levels of caffeine are found in breast milk between 1-2 hours after consumption.3  As caffeine leaves the maternal blood serum, it also decreases in breast milk.  Consumption of less than 300 mg/day is typically considered to be safe for a breastfeeding baby. 4 However, all babies are different and if you notice symptoms of sleep disturbance, decrease in your baby’s appetite, irritability, and/or hyperactivity it is possible your child is reacting to the caffeine in your breast milk.  Decreasing your caffeine intake, switching to decaffeinated drinks, and waiting for several hours to nurse after caffeine intake are all strategies than can reduce the amount of caffeine your baby is exposed to. Also, preterm or sick infants might be less able to metabolize caffeine and therefore impacted to a greater degree by small amounts of maternal consumption.

How Much Caffeine is in My Favorite Drink?

Caffeine Content of Various Drinks and Foods
DrinkServing SizeCaffeine (mg)DrinkServing SizeCaffeine (mg)
Starbucks Filter Coffee, Short8 oz160 mg Starbucks Hot Brewed Tea, ShortAllvaries
Starbucks Filter Coffee, Tall12 oz240 mgStarbucks Chai Tea Latte, Short8 oz50 mg
Starbucks Filter Coffee, Grande16 oz320 mgStarbucks Chai Tea Latte, Tall12 oz75 mg
Starbucks Caffe Latte, Short8 oz75 mgStarbucks Chai Tea Latte, Grande16 oz100 mg
Starbucks Caffe Latte, Tall12 oz150 mg
Starbucks Caffe Mocha, Short8 oz85 mg
Starbucks Caffe Mocha, Tall12 oz95 mg
Starbucks Americano, Short8 oz 75 mg
Starbucks Americano, Tall12 oz150 mg
Starbucks Cappucino, Short8 oz75 mg
Starbucks Cappucino, Tall12 oz75 mg
Starbucks Espresso, Solo75 mg
Starbucks Espresso, Doppio150 mg
Starbucks Macchiato, Solo75 mg
Starbucks Macchiato, Doppio150 mg
Starbucks Caffe Americano, Short8 oz75 mg
Starbucks Caffe Americano, Tall12 oz150 mg
Starbucks Caffe Americano, Grande16 oz225 mg
Starbucks Cappuccino, Short8 oz75 mg
Starbucks Cappuccino, Tall12 oz150 mg
Starbucks Cappuccino, Grande16 oz150 mg
Starbucks Caffe Misto, Short8 oz75 mg
Starbucks Caffe Misto, Tall12 oz115 mg
Starbucks Caffe Misto, Grande16 oz150 mg
Hot Drinks
Starbucks Hot Chocolate, Short8 oz10 mg
Starbucks Hot Chocolate,Tall12 oz15 mg
Starbucks Hot Chocolate,Grande16 oz20 mg
Starbucks Frappuccino, Tall12 oz 70 mg
TeasServing SizeCaffeine (mg)
Starbucks Chai Tea LatteShort (8 oz) / Tall (12 oz)50 mg / 70 mg
Starbucks Green Tea LatteShort (8 oz) / Tall (12 oz)25 mg / 55mg
Soft Drinks
DrinkServing SizeCaffeine (mg)
Coca-Cola12 oz30-35 mg
Coke Zero12 oz35 mg
Diet Coke12 oz38-47 mg
Pepsi12 oz32-39 mg
Diet Pepsi12 oz27-37 mg
Dr. Pepper12 oz36 mg
Mountain Dew12 oz46-55 mg
Barq's Root Beer12 oz18 mg
Energy DrinksServing SizeCaffeine (mg)
Red Bull8 oz76 mg
Full Throttle8 oz70-72 mg
Monster8 oz80 mg

Does Chocolate Contain Caffeine?

Yes, chocolate does contain caffeine but it depends on the type of cocoa beans and the degree of fermentation as to how much caffeine is present.  Typically, chocolate has caffeine levels typical to decaffeinated teas and coffees. 5 Caffeine is not typically listed as an ingredient in chocolate because it is a part of the cocoa itself and not an added ingredient, much the same way as water would not need to be listed as an ingredient in a whole watermelon.

Chocolate also as theobromines which have a similar impact on the body’s nervous system as caffeine. 6   But, as with caffeine, the levels in chocolate are quite low.  One oz of milk chocolate has 6 mg and 1 oz. of dark chocolate has 20 mg. 7 Chocolate does not usually cause problems in breastfeeding babies.

Marijuana and Breastfeeding

The use of marijuana (cannabis) is on the rise in the United States.  Two states – Colorado and Washington – legalized cannabis by state referenda in the 2012 elections and nearly half of the remaining 50 states have laws legalizing its use in various ways.  Whether as an illegal drug of abuse or for medical purposes, more and more people are using marijuana to varying degrees.

The National Institute on Drug Abuse has published research based on national surveys showing that 19% of 18-25 year olds have used marijuana in the past month and 4.8% of those ages 26 or older have done so in the past thirty days.1 This, coupled with the fact that up to half of all pregnancies in North America are unplanned, has lead many pregnant and lactating women to want accurate information about whether or not marijuana has negative effects on a fetus or nursing baby.2

Is marijuana safe to use while breastfeeding?

The American Academy of Pediatrics states that since marijuana can be found in breast milk and there is concern about a baby’s neurobehavioral development over the long-term, marijuana should not be used during pregnancy or breastfeeding.3 THC, the active component in marijuana, is highly lipid soluble, which means it readily passes into breast milk.  The body also stores THC for weeks to months, so babies will continue to show trace amounts of the drug in their bodies for several weeks after a breastfeeding mother no longer uses it.

While cannabis readily passes from breast milk to a baby’s system, the amounts found in breast milk are still considered insignificant to producing psychoactive affects in a baby even with mothers who are chronic users.4 The effects of THC in breastfed babies have not been well studied, though the potential for high concentrations of accumulation are possible with chronic use.5

How does marijuana impact a breastfeeding mother?

A mother’s breast milk supply may be negatively impacted by marijuana use.  Prolactin, a hormone that is responsible for both initiating and maintaining lactation, is reduced with marijuana use.6 Since prolactin is essential for milk production, a low milk supply could be yet another negative side effect.  And, while using marijuana, a mother may experience hallucinogens, euphoria, and then deep sleep – all of which could prevent her from taking care of her baby’s needs.

How does marijuana use impact a baby?

Though the impact of maternal marijuana use is greater while a baby is in utero than during breastfeeding, a newborn baby’s brain is rapidly growing and developing and there is a significant chance that marijuana can negatively impact this growth.  Not only can the THC in breast milk have a negative effect on a baby, but the environmental exposure will also impact an infant.  However, in this case, breast milk will have a more ameliorating affect with its living antibodies than manufactured formula.

Regardless, a mother who is breastfeeding and using marijuana should speak with her health care provider and seek appropriate counseling and help so she can continue to breastfeed her baby.  Breastfeeding promotes bonding and security and its unique makeup of vitamins, minerals, and immunological properties can help a baby achieve optimum growth and development – something especially important if they have been exposed to marijuana in utero.

While individual mothers may need to discuss the risks and benefits of marijuana use during pregnancy or lactation with their health care provider, the overall message to women is that marijuana use during pregnancy and lactation should be avoided.  Any woman of childbearing age should consider the potential impact of marijuana usage and either take precautions against pregnancy or discontinue its use during this time in her life.

Smoking and Breastfeeding

Is it safe to smoke while breastfeeding?

Everyone knows that smoking cigarettes is hazardous to their health.  And while the risks of smoking during pregnancy are well documented with increased incidences of preterm birth, low birth weight, and increased risk of abortion or stillbirth, much less is publicized about smoking and breastfeeding. Many mothers who smoked in the past want to make changes now that they have a baby, but change can be hard and take time.

They understand the importance of breast milk for their babies but wonder if the benefits are negated if they still use nicotine.  The bottom line is that even though nicotine does pass into breast milk, and mothers should seek to stop smoking or at least use a nicotine patch, breastfeeding is still a better option than formula feeding, for a variety of reasons.

The CDC states the following:

“Mothers who smoke are encouraged to quit, however, breast milk remains the ideal food for a baby even if the mother smokes.  Although nicotine may be present in breast milk, adverse effects on the infant during breastfeeding have not been reported.  AAP [AmericanAcademy of Pediatrics] recognizes pregnancy and lactation as two ideal times to promote smoking cessation, but does not indicate that mothers who smoke should not breastfeed.”1

What are the various forms of nicotine?

  • Cigarettes – Smoking 17/day is proportional to the 21 mg nicotine patch.  The 14 mg and 7 mg patches have significantly less nicotine than cigarette smoking.
  • Patch – This is considered a safer option than smoking.  Nicotine amounts don’t have a sharp rise and decrease as with cigarettes or gum so timing breastfeeding is less important.
  • Inhaler – Dispenses low levels of nicotine and even habitual users will typically incur less nicotine than smoking a pack of cigarettes each day.  There is minimal transfer of nicotine to breast milk.
  • Gum – Maternal serum levels fluctuate as with smoking cigarettes.  The faster the gum is chewed the greater the peak levels of nicotine.
  • E-cigarette – Considered safer than smoking a cigarette. Peak blood nicotine levels similar to the nicotine inhaler and minimal in breast milk.2

How can I reduce the levels of nicotine my baby is exposed to?

Smoking (or using gum, inhaler, etc.) immediately following breastfeeding and then waiting a couple of hours before nursing again allows the nicotine in breast milk to decrease before each breastfeeding.  The half-life of nicotine is 95 minutes – that means it reaches its peak in the maternal blood stream at this time.  It takes 5 half-lives to clear a drug completely.  (You can read more about this on how medications affect baby.)

Smoking and then breastfeeding right afterwards greatly increases the amount of nicotine in breast milk.  However, if your baby wants to nurse after smoking it is better to breastfeed than give formula.

It is important to smoke away from your baby.  Smoking in a separate, well ventilated room can greatly reduce the amount of second hand smoke your baby is exposed to.  Decreasing the number of cigarettes a mother smokes or switching to a nicotine patch is also beneficial.

What effect does smoking have on a mother’s breast milk?

Smoking cigarettes can have a detrimental effect on a mother’s milk supply, milk ejection reflex, and a baby’s weight gain.3  In a mother with an ample supply of milk this may not be as much of a concern, but with a mother with smaller breasts or less glandular tissue (breast size does not equal breast milk capacity) this could mean the difference of being able to provide enough milk for her baby versus having to supplement.  Slow weight gain in a baby could lead to failure to thrive, a very serious diagnosis.  Babies of mothers who smoke should have their weight watched diligently to ensure adequate growth.

The fat content of breast milk in mothers who use nicotine is also lower.4  Fat in breast milk is something that is affected by maternal diet and mothers who smoke not only have lower fat content but the fat has nicotine in it.  Fat is important for infant growth and brain development.  But, just because nicotine affects the fat content of breast milk does not mean the alternative – formula – is superior; it’s not.

What are the infant concerns when a mother smokes?

Mother’s who smoke are less likely to breastfeed.  Those that do breastfeed are more likely to breastfeed for a shorter duration than mothers who don’t smoke.5  Breastfeeding has tremendous health benefits for mothers and benefits for babies so anything that decreases the duration of a mother-baby breastfeeding relationship is significant.

Maternal smoking also exposes a baby to the dangers of second-hand smoke.  This can cause increased allergies and respiratory illness as well as unsafe carbon monoxide levels.6

These infant concerns continue to exist when a mother formula feeds her baby while smoking.  In fact, formula feeding while smoking is even more harmful than breastfeeding and smoking.  A baby receives the vast majority of smoking side effects from second-hand smoke rather than nicotine in breast milk.  In fact, the nicotine that does pass through breast milk is easily outweighed by the living, changing, and unique qualities of breast milk that impart antibodies and immunities to a baby to help him fight disease, infection, and illness, as well as equipping his immune system to maturity so it will be strong and prepared to work to its full potential over the course of a lifetime.

A baby who is regularly exposed to second-hand smoke especially needs the benefits of breast milk!

So, while it is important for a mother to try to decrease or cease smoking, it is far better for a mother to smoke and breastfeed than to stop breastfeeding in order to continue smoking.

How Medications Affect Baby


Knowledge of how a drug enters breast milk is important to understanding how a particular medication can affect your baby, but it is only part of the picture.  It is also critical to evaluate how a baby’s body metabolizes the drug.  Some medications, though they enter the baby’s system via breast milk, are still not able to circulate throughout his body.  Others, though only small amounts may be ingested, are fully utilized and should be used with greater caution.  Therefore, understanding what happens in a baby’s body once the drug enters via breast milk will help in selecting the best medication with the least risk to your baby.  Understanding a drug’s oral bioavailability and half live, as well as evaluating the amount of breast milk consumed and age of baby are all important factors.

What is oral bioavailability?

A drug’s ability to pass into breast milk is only part of the picture.  It is also important to know what happens to the medication once it enters the baby’s system.  A drug’s oral bioavailability is the amount of medication that can reach a baby’s systemic circulation.  This is the only amount of a drug that will usually have an impact.  Some drugs are so poorly absorbed in the infant they are unlikely to cause any problems what so ever.  Therefore, choosing drugs with poor bioavailability is a good strategy.  (Others, though not well absorbed, can become concentrated in the gastrointestinal system and can cause diarrhea, thrush, etc.)

What drugs have poor bioavailability in infants?

According to Breastfeeding and Human Lactation, 4th ed. by Riordan and Wambach, there are a variety of medications with poor bioavailability, thus having a low risk in babies.  These medications are as follows:

  • Heparin
  • Insulin
  • Large molecular weight proteins
  • Interferons
  • Infliximab
  • Etanercept
  • Omeprazole
  • Lansoprazole
  • Aminoglycoside antibiotics
  • Third generation cephalosporins
  • Inhaled beta agonists
  • Inhaled steroids
  • Most topical preparations
  • One-time injection of local anesthetic
  • Acute use of medications (as the overall dose transferred to infant over time is so low)

Half Life

A drug’s “half life” is the time it takes a drug to reduce its plasma concentration by half. So, from the time of ingestion, how long does it take the drug to reduce by half?  Some drugs have a short half life, just a few minutes or hours.  Others have a much longer half life – a few days even.  With breastfeeding, drugs with a shorter half life are better.  It takes five half lives to fully clear a drug from maternal plasma – reducing 50% each time.

A drug with a short half life of say 1-3 hours, could be strategically taken between feeds.  Nursing your baby and then taking the medication could mean the drug is already reduced by half before your baby nurses again.  (Think:  even at the maximum amount of the drug in maternal serum it is probably less than 1% that the baby will ingest via breast milk.  Add to this the ability to time feedings and the amount ingested by the baby will be even less.)

If given the choice between a medication that you take every few hours versus a long-lasting dose ingested less frequently, select the dose you can take more often.

Age and Stage of Baby

The ability of a baby to metabolize a drug is different based on his age. Newborns generally metabolize a drug more slowly than a six month old.  Older infants, 6-18 months, can usually metabolize and handle drugs much more efficiently.  Caffeine is a good example.  It’s half-life in a newborn is 97.5 hours, but 2.6 hours by the time a baby reaches 6 months.

Not only is the age of the baby important, but the quantity of breast milk ingested.  Though more of a medication is able to pass into breast milk during the first few days postpartum, the amount of milk a baby is able to drink is so small he is not ingesting a greater volume of a medication.  Also, a toddler who is only drinking milk a couple times a day is receiving much less of a medication via breast milk than a two month old solely fed on breast milk.

How much of a drug is considered safe?

For most drugs, ingesting 10% of the maternal dose is considered safe. 1  With some drugs (for example, fluconazole and metronidazole) the dose can be much higher than this.  And usually, the dose ingested is less than 1%.  Thus, most medications truly are compatible to take while breastfeeding.  This is especially true in light of the 1000s of studies that show the detrimental side effects of formula.

Is Breast Milk Compatible with Medications?

woman holding pillsIntroduction

Most mothers will take some sort of medication while breastfeeding.  Whether it is an herb, high-dose vitamins, prescribed medication, or something else, finding accurate information as to the safety and efficacy of continued breastfeeding is important.  The good news is that most drugs are completely compatible with breastfeeding!  The following information will help you maneuver through the landmines of finding reliable information.

Are drug inserts reliable?

Drug inserts are not a reliable form of information as to the drug’s impact on baby via breast milk as the drugs are not tested on breastfeeding women.  To protect them from litigation, drug manufacturers place a blanket statement that their drug is not compatible with breastfeeding.  The Physician’s Desk Reference (PDR) is based on these drug inserts.  This can make finding correct information challenging and frustrating for both a breastfeeding mother and her doctor.

Are there any drugs which are safe to take while breastfeeding?

Yes! In fact, most medications are safe to take while breastfeeding.  There are some that are safer than others.  And there are typically multiple medications which can be prescribed for the same illness, so understanding which drug will have the least impact on a mother’s breast milk and baby are important considerations for a breastfeeding mother.

The benefits of taking a medication should always be weighed against its potential harm to a breastfeeding baby.  The known risks of formula should be weighed against the potential risk of the medication.  If a drug is not essential, delay its use until later.  This is true for many herbs as well.  Yet, when a mother has a need for medication, understanding how medications pass into breast milk and how a baby’s body metabolizes the drug can help a mother and her doctor make the most informed decision possible.

What is considered a safe amount of medication to receive via breast milk?

For most drugs, ingesting 10% of the maternal dose is considered safe. 1  With some drugs (for example, fluconazole and metronidazole) the dose can be much higher than this.  And usually, the dose ingested is less than 1%.  Thus, most medications truly are compatible to take while breastfeeding.  This is especially true in light of the 1000s of studies that show the detrimental side effects of formula.

Where can I go for accurate information?

If you doctor recommends weaning or “pumping and dumping” your milk while taking a medication, make sure you talk with a lactation consultant first.  There are many great resources with research and information on drugs and their impact on babies via breastfeeding.  Arming yourself with knowledge, you can then share research and information with your doctor to select the most appropriate medication for your needs that will also allow you to continue nursing your baby.

Medications and Mother’s Milk by Thomas W. Hale, Ph.D. is an excellent resource book.  This website is another great resource for accurate breastfeeding and medications information as is the LactMed search on the sidebar of this article.

When treatment is truly not compatible with breastfeeding…

This is a difficult time and breastfeeding mothers need lots of love, support and encouragement.  Is it possible to pump and dump (or freeze) your milk?  Sometimes breastfeeding need only be interrupted for a time (hours or days) and then can be resumed.  During this time, it is important to keep up your milk supply by pumping each time your baby feeds.  If you don’t have enough breast milk for your baby, you could use human donor milk or formula.  By pumping and keeping up your supply, you can then return to nursing as soon as it is safe to do so.

Other times mothers need help and support in weaning.  Usually in this circumstance there is not time to wean slowly.  Care not only needs to be made at keeping the mother comfortable but supporting both mother and baby emotionally.  If you find yourself in this circumstance, rejoice in the wonderful nursing relationship you were able to have with your baby.  Every drop of breast milk was a precious gift and you should be very proud of yourself!  Also, remember that this is not the end of your relationship with your baby but the beginning of a new era.  With the warm and loving bond you have already forged, this next phase can be even better.

If your baby is under a year and you are concerned about giving formula, check to see if there is a human milk bank you can get donor milk from.  Alternatively, there may be friends in your local community who informally share human milk.

Click here to read more about how medications affect breast milk and how drugs in breast milk affect your baby.