Glowing Green Milk

Mammograms aren’t fun for a variety of reasons. Perhaps the most obvious is that they involve smashing the breasts between two plates so that they resemble — as much as is possible for semi-spherical body parts — pancakes. I have a mammogram coming up shortly, and to be honest, I’m less concerned about the former, and am more bothered by the fact that I’m old enough to be on my second mammogram. Apparently, however, doctors don’t like it when mammograms converge with lactation in space-time. For instance, the health provider who prescribed my upcoming mammogram told me, “You may want to pump and dump afterward, because of the radiation.” When I actually called to schedule the procedure, I was told that they would be doing an ultrasound instead, because I was lactating and they didn’t want to “expose my milk to the radiation.”

Now, I teach chemistry, so I’m well aware of how common are fears and misconceptions about radiation. I have to admit, however, that I didn’t think doctors’ offices would share (or propagate) those fears and misconceptions. In any case, I thought it would be worth addressing why mammograms (and MRIs, and x-rays) won’t make your milk glow green (as cool as that would be), and why you don’t need to pump and dump if you have to have one of these procedures. (Incidentally, Kellymom has lots of information on what is and what is not safe during lactation.)

We tend to think of anything called “radiation” as being bad, and generally associate exposure to radiation with things like cancer, Chernobyl, and Spiderman. Thankfully, most radiation can’t produce cancer, and unfortunately, no radiation has the ability to produce Spiderman. “Radiation” is really just a term for radiant energy, which is even more technically referred to as electromagnetic radiation, or EMR. EMR encompasses many different types of phenomena that we don’t necessarily think of as related to one another. These include — but are not limited to — x-rays, visible light, and radio waves. Without getting too deep into the physics, all EMR has a frequency, and the frequency of the EMR determines the type of radiation. It’s possible to draw a limited analogy to sound here; the pitch of a sound is a function of its frequency, so frequency determines the “type” of sound. The analogy between sound and EMR doesn’t take us far, however, and the important point here is that high-frequency EMR has high energy.

From Wikipedia, Philip Ronan

The reason all this matters is that some EMR can interact with molecules, and the way EMR interacts with a molecule depends upon the type of EMR. Think of a molecule as being made up of particles (called atoms) connected by springs (bonds). The springs (bonds) naturally bend and stretch, and very high energy EMR can “overstretch” the springs and make them break, like this:

From Hendrickson, K. "Chemistry In The World" 2010.


Break the bonds, and you destroy the function of the molecule. If the molecule that gets broken is, say, DNA — your genetic material — then bad things happen, including disease, cancer, aging, and so forth. The only types of EMR with enough energy to break bonds in molecules are UV light, x-rays, and gamma rays (collectively called “ionizing radiation”). These are the only types of EMR that, consequently, can cause cancer and so forth (note that despite their bad reputation in some circles, microwaves have completely insufficient energy to cause cancer). Ok, so x-rays can cause cancer, as can mammograms (which rely upon x-rays). MRIs can’t, since they don’t use ionizing radiation, and rely instead upon the behavior of atoms in a magnetic field.

If x-rays fall into the category of ionizing radiation, why shouldn’t we worry about the milk that gets shot full of x-rays? The answer to this is simply that very, VERY few phenomena can actually make things radioactive. X-rays, and even gamma rays (which come from nuclear reactions and can cause a variety of cancers, radiation poisoning, and so forth) can’t make the things exposed to them radioactive. If you were exposed to nuclear fallout (like from the Chernobyl disaster), you could temporarily “become radioactive,” but only because nuclear fallout includes bombardment with subatomic particles called neutrons (among other things). If you have certain types of radioactive material introduced into your body, you can emit radiation due to the presence of the radioactive material. However, it is impossible for you (or your fluids) to become radioactive as a result of x-ray exposure. The only thing the x-rays could theoretically do to your milk would be to break down some of the proteins and other molecules (though they’re unlikely to, because the dose is so small), and furthermore, this wouldn’t affect the quality — or the safety — of the milk.

I Googled lactation and mammography, because I wanted to know what it was (assuming most medical professionals know there’s no risk of radioactive milk from a mammogram) that would cause a health practitioner to put off a mammogram on a lactating woman (which, according to Google, happens quite often). It turns out that practitioners worry about the “goo-factor.” Breast milk is a bodily fluid, and apparently the staff of imaging clinics is concerned that it will, well, squirt on things. Not that it does, generally speaking…but regardless, this appears to be a major motivating factor with regard to lactating women and the medical profession’s desire to keep them, and their squirting milk, away from those hard-to-clean mammography machines.


Science Bottom Line:* There is no danger to your milk if you have to have a mammogram or x-ray while you’re lactating. There is, as always, some danger to you personally any time you’re exposed to ionizing radiation, which is why it’s always important to weigh the risks against the benefits when you need to have imaging done. You don’t need to pump and dump unless you’re engorged.


What medical procedures have you wondered (or worried) about during lactation?



6 Comments (+add yours?)

  1. Ashley @ C is for Cockerham
    Nov 17, 2011 @ 02:18:33

    Thank you so much for this well-written and factually correct article addressing common misconceptions about medical procedures and radiation. I am appalled that the health professionals you mentioned don’t understand the basic radiation principles of mammography enough to know that milk does not activate or become radioactive as a result of such a procedure. As a medical health physics professional, I am frequently frustrated by the rampant misinformation published about radiation, so this post was a refreshing read. You are correct that there is absolutely no need to pump and dump following a mammogram, x-ray, or MRI. As a matter of fact, there are rarely times when pumping and dumping is necessary at all. Would you mind if I linked your post to my blog?


  2. Megyn @Minimalist Mommi
    Nov 17, 2011 @ 05:16:30

    Thank you for such great info! I too had x-rays & MRI’s while breast feeding. I was told that the only reason I would need to pump & dump is if I received contrast dye. I just avoided the dye to avoid the pump & dump.

    It’s truly is SO nice to read real, well researched information from a blog!!! It’s such a change from the blogs I’ve been reading that add research to support their claims, when it’s obvious that they have not read the article or didn’t quite understand it. So refreshing!!


    • SquintMom
      Nov 17, 2011 @ 16:27:08

      Thank you! And actually, even most contrast dye is ok. Kellymom has great info on this. Some dye is injected IV, and that’s a bigger concern (though the radiation is very short-lived), and may warrant a few hours or so without breastfeeding, depending upon the specifics. Dye that isn’t injected IV (like the gadolinium I’m having injected into my shoulder) enters the bloodstream very, very slowly and in only very small amounts at once, and is therefore considered safe during lactation per several studies..


  3. Alice Callahan (@scienceofmom)
    Nov 26, 2011 @ 06:55:42

    On a somewhat related note, I had my wisdom teeth pulled when BabyC was 4 months. I was shocked at the differences of opinion as to how to handle nursing if I took the sedation drugs for the procedure. The oral surgeon suggested that I pump and dump for 4 days to A WEEK! I talked to him on the phone before the procedure, and he told me to start storing milk or consider using formula during that time. I think I started crying when he told me that. I am so glad that I didn’t take his word for it. After talking to my pediatrician and talking to someone at the OTIS hotline and reading a few papers myself, I decided to pump and dump 4 hours after the drugs, and that was being conservative. BabyC took her only successful bottle during that time (not for lack of trying before), so even that amount of time was nerve-racking for me. I found the OTIS person SO helpful – that’s a great service if you ever have questions about exposures during breastfeeding or pregnancy. I used it to check lab exposure questions during my pregnancy, too.


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