Sometimes when I am nursing in the mornings, I have the very strong urge to have a bowel movement. There are even times I have to stop nursing completely and run to the toilet, leaving my baby looking confused and still hungry. What’s going on?
If you’re not interested in talking about poop, I recommend skipping this newsletter! If you’re like me and are always interested in talking about poop, let’s dig in, shall we?
There are random internet pages (like this one) that talk about how breastfeeding can exacerbate constipation because it can contribute to dehydration. Clearly, this is not my problem. However, I also found this old reddit post titled, “Urge to poop while breastfeeding?” Hooray! I’m not alone!
Unfortunately, I could not find a study that examined what I was interested in (“Can breastfeeding increase the urge to have a bowel movement?”) When it comes to the research literature, there are a lot of studies that examine how breastfeeding affects infants and their bowel movements. But that doesn’t answer my question!
Eventually, I came across this study that examined whether administering oxytocin could help treat chronic constipation in women1. I’ve written about oxytocin before (see below), a hormone that is released during, among other things, uterine contractions throughout labor and milk release during lactation. If oxytocin is released when I am breastfeeding, maybe it’s also responsible for my need to go number 2?
In the Introduction, Ohlsson and colleagues (2005, Neurogastroenterology and Motility, p. 698) write:
“We have noticed clinically that women with constipation have been improved during lactation, a state in which the levels of oxytocin in plasma are high.”
INTERESTING!
This Swedish2 research team were doing the precise type of science I was hoping to find. In another study by the same team titled, “Oxytocin stimulates colonic motor activity in healthy women,” they found that administering oxytocin in women led to colonic peristalsis (i.e., involuntary constriction and relaxation of muscles in the colon, which is responsible for pooping!) Specifically, the authors note that oxytocin administration led to specialized contractions that “have been proposed to be important for mass movements, as they have been associated with an urge to defecate” (Ohlsson et al., 2004, Neurogastroenterology and Motility, p. 237).
So there you have it. While the evidence remains circumstantial, I am grateful for Dr. Ohlsson and their team for helping me better understand my body. Oxytocin was the culprit for why I had uterine cramps when my first baby cried. Now, it seems like it is responsible for my urge to poop during my morning nursing sessions. Bodies are fascinating.
Unfortunately, the authors did not find a difference between oxytocin administration and a placebo in helping these women with their chronic constipation. However, women who were administered oxytocin reported improvements in abdominal pain, discomfort, and depression.
I remain incredibly amused at the coincidence that my decision to make a reference to The Girl With the Dragon Tattoo was before I realized that all the research I found was from Sweden!