The Science of Breastfeeding on Meds, or Formula is Not Neutral

“The mistake many doctors make is in thinking that formula is neutral. It’s not.”

I am fairly certain that those were Dr. Christina Smillie‘s exact words when she began to explain to me (and my husband) the benefits of breastfeeding and why they could outweigh the risks my medication might pose. I came to her because I wanted to breastfeed my baby, at least during our hospital stay. She wasn’t trying to change my mind or convert me. The appointment lasted over two hours. It was pretty amazing! She was able to give me exactly what I wanted: a scientific explanation for abandoning the fear I carried that my milk would hurt my child.

Dr. Smillie recommended breastfeeding because, from her perspective, the benefits of breastfeeding a baby make even less-than-perfect breastmilk healthier than formula. I am not saying that formula is bad. I already wrote that we use formula. But breastmilk is pretty amazing stuff, and nothing we manufacture can measure up to it.

I didn’t just take the doctor’s word for it; I read the article she gave us from the journal Pediatrics, published by the American Academy of Pediatrics called “Breastfeeding and the Use of Human Milk.” This is a ten-page academic article, not including notes and citations, so I’ve included the link. The article addresses both the benefits of breastfeeding and the risks of taking meds while nursing, go and check it out if you want to read the benefits. Basically, breastmilk is good for babies in every possible way, from supporting the immune system to lowering an infant’s risk of contracting a respiratory infection.

But what about those risks because of my medication? There’s a whole section on “Maternal Medications,” and they state first that there are very few medicines that are “contraindicated” (the AAP recommends that you not breastfeed because of them). There are many, and they specifically mention psych meds, that we just know very little about, especially when it comes to how much medicine is in a mom’s blood stream or milk supply. But then, there’s what we do know: of the drugs that we do have data on, Zoloft is one of the most-studied and “least problematic.” Effexor and Zoloft are not the same. They are similar enough for me to feel ok about taking that risk. Klonopin? We just don’t know enough to say that it is probably not problematic. The combination of the two? No data.

That’s kind of scary, I admit. But the same article offers some perspective by listing the classes of drugs that are dangerous enough for the AAP to recommend formula over breastmilk. There are four: amphetamines, chemotherapy agents, ergotamines, and statins. Why does this offer perspective? Because these drugs have extremely intense side effects, unlike the anti-anxiety meds and anti-depressants that I takeThey also directly effect basic body functions, unlike my meds.

Speaking of basics, Dr. Smillie offered some perspective in the midst of all this science by explaining the way that alcohol enters breastmilk as a point of comparison. Alcohol enters everyone’s blood stream and every lactating woman’s milk supply at exactly the same rate (unlike antidepressants). A great resource for breastfeeding moms is the website Kelly Mom, which supports Dr. Smillie’s assertion that “less than 2% of the alcohol consumed by the mother reaches her blood and milk.” The example the doctor used was that of a mother who is legally drunk here in Connecticut, with a blood alcohol level of .08. If she nurses her baby at that blood alcohol concentration (BAC), her baby will end up consuming 2% of the alcohol in her blood and will have a BAC of less than 2% of .08. While a fetus shares his mother’s blood stream and would also share her BAC, a baby is just taking a drink of a liquid that contains less than 2% of the alcohol in his mother’s blood stream. That baby would then have a negligible amount of alcohol in his blood stream, even though his mom was very drunk when she fed him.

My medication is metabolized differently than alcohol, but even if my baby got 2% of it at its peak concentration in my body, he would still be getting a tiny amount. In fact, one study that did look at breastfed infants whose mothers took Klonopin found that “ten of eleven … had no detectable” levels of the medication. Studying eleven infants is not exactly conclusive. But in the database Lactmed’s summary of research on Klonopin and breastfeeding, only one infant seemed to show any side effects from Mom’s meds. There’s more research on Effexor, but Dr. Smillie’s point was clear: it’s probably safe, watch the baby for side effects, don’t worry too much.

We supplemented with donor milk to reduce the amount of medication Walt got in the early days for our own peace of mind, because as his body gets bigger, the same amount of medicine has a smaller impact on that body. It also gave me time to see whether or not Walter was exhibiting any symptoms after consuming my milk. By the time we ran out of donor milk, I had watched him and couldn’t find any sign of any symptom.

Please, ask questions. It took me a long time to absorb all of this information, and I’m really not sure I have reached the point where I can explain it to other people.


  1. I didn’t have to consider those things when my youngest (who just turned 23, Heaven help me) was a baby because I wasn’t on meds at the time but Lord knows I understand the desire to breastfeed and the fear that I wouldn’t be able to. He was already a miracle child as we were infertile for 10 years before him and he was a total surprise. Difficult, high risk pregnancy followed by C section. And then … I had flat nipples (never heard of such a thing before then) and he had an extraordinarily high palate. He lost a lot of his birth weight and became very jaundiced over the first couple of weeks, The doctor finally sat me down and told me breastfeeding was not worth risking my baby’s life. Now I wish I had know that I could try doing both. At that time everyone was indicating that it was an either or. You breast feed or you bottle feed. Not both! Oh well … he’s 6’5″ and remarkably well grounded so I think he turned out ok! And he doesn’t care in the least whether or not he was breast fed. LOL!

    Good for you for researching and finding support and answers! Proud of you!

    January 16, 2013
    • Anne-Marie said:

      Honestly, I’ve heard stories like that from women who have given birth in the last year. I had heard of “supplementing” but it seemed very all-or-nothing to me, too, at first. It’s a really difficult position to negotiate from if a doctor or nurse thinks they have the answer for your baby’s health; they are genuinely concerned and Mom has no medical training, just a strong instinct. It’s a shame that they didn’t encourage you to keep trying or get in touch with support people! But as you say, your miracle boy grew up big and strong. My hope is just that putting my story out there gives someone else some support or a new idea. Thanks for reading!

      January 16, 2013
  2. Misty said:

    Great to read this, as I just started back on Zoloft (my daughter is 3 months too – I first took zoloft after my first daughter was born for PPA). So far it’s been 2 weeks and I’ve been increasing the dosage really slowly, but have not noticed any improvement yet (I’m still not up to the full dosage). I started getting worried about whether I might need to try Effexor again, which really worked in the past. However, as you’ve mentioned, not a lot of data on effexor and breastfeeding. Anyway, hoping that the zoloft takes effect soon and I can find some relief!

    January 21, 2013
  3. Marla said:

    Did your baby go through withdrawal when you stopped breastfeeding while taking klonopin? My ex husband kidnapped my daughter for a week and I was pumping and my butt off and my supply became low and due to all this stress I got prescribed klonopin. I got her back and due to the ugly custody battle am choosing to stay on the medication as well as therapy and obviously a psychiatrist. Please please please email me back I know this thread is old but I’m desperate to know my daughter will be okay

    April 10, 2017
    • Anne-Marie said:

      First: please, please consult a pediatrician! Blog posts , especially old ones, are not reliable sources of medical advice. I will do my best to tell you about my experience, and hope it gives you some comfort. I am so sorry for what you’ve been through.

      We didn’t stop breastfeeding until my son was almost 3, so it was obviously a really gradual weaning.

      Withdrawal for someone getting an adult’s therapeutic dose can be painful, yes, but the amount of medication in any given feeding is far less that. What I was told was this: imagine cutting your pill into 100 pieces–your baby is probably getting something like less than two of those crumbs. And even that isn’t consistent, because breastmilk is mostly fat, protein, and water, and psychiatric medication is designed to get to your brain, NOT get absorbed into fat or protein cells along the way.

      Second, it is much more likely to see withdrawal in a newborn, if medication is taken during pregnancy. I took a fairly high dose during pregnancy, which means that my son shared that medication, because we shared a blood stream. If he went through withdrawal, we would have seen the symptoms immediately after his birth, and while a pediatrician at the hospital thought “maybe” no one could say for sure, because they had seen babies behave just the same way whose mothers had taken no medication during pregnancy. I am highly skeptical of “withdrawal syndrome” alarmists, because my baby was so wonderfully healthy, and I have yet to read about babies born *without other factors* whose symptoms clearly point to withdrawal. But again: that’s withdrawing from sharing the same dose via bloodstream, NOT MILK.

      If you aren’t seeing any major changes in your daughter’s behavior or body, and you didn’t mention any, then she is more than likely fine! But again, if you are worried, ask her pediatrician to look for signs of withdrawal syndrome. That won’t hurt anyone. Throw the “mom guilt” out the window–I cannot imagine a more stressful situation. There is perhaps a huge risk for you if you DO NOT medication prescribed to you at a time like this!!! You cannot sacrifice your health for your child; it simply does not work that way.

      April 10, 2017

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