I first wrote about diastasis recti almost 4 years ago in a post with the oh so creative title What is Diastasis Recti? In the last 4 years, a plethora of fitness personalities have come out with programs promising to close your diastasis recti (DR), but the evidence base for how to do that or even how to define DR has not kept pace with all this new advice. If anything, we have more evidence showing that what we thought worked doesn’t actually work, which has muddied the DR waters. I’ll talk about that in a future post.
However, for now, let’s focus on what should be a simple question: How do you know if you have diastasis recti? The market for those DR programs depends on women assuming they have abdominal gaps that need to be closed. This may or may not be true. They may or may not have DR. The gaps may or may not need to close. And, what these personal trainers prescribe may or may not do anything. As you can see, a lot of uncertainty swirls around the DR world.
Sometimes, I get an email from a mom asking for advice about how to close her abdominal gap. More times than I can count, the mom will reference a gap of 1 or 2 finger-widths, and I’ll write back saying she can see a physical therapist if she is experiencing any bothersome physical problems but that she doesn’t actually have a DR. A gap between the rectus abdominis muscles is normal. Everyone has a gap because it is a paired muscle. Indeed, this gap normalcy is why defining diastasis recti is so hard. At what point does the gap go from a completely normal anatomical setup to a pathological separation? And at what point can we say a gap has been “closed”?
After having my children, I could fit my fist between my rectus abdominis muscles, so I was pretty sure I had out-of-the-norm anatomy. My physical therapist confirmed this. Over time, my gap narrowed (How I Narrowed My Diastasis Recti) but I have no idea at what point the gap transformed from obvious DR to not a DR.
This lack of precision is why many personal trainers and physical therapists suggest focusing on physical symptoms rather than the size of a gap. This is excellent advice. How you feel and move is much more important than an arbitrary cut-off in gap size.
Nonetheless, inquiring minds still want to know “Okay, fine, how you feel is important, blah blah blah, but is the size of my gap normal or not?” Fair enough.
Luckily, researchers have focused on the diastasis recti definition conundrum. This makes sense. How can you study interventions for closing a DR without a good definition? The systematic reviews are frustrating because different researchers use different cut-offs and different ways of measuring. This is a problem when trying to find clarity among studies that can lead to evidence-based advice.
Creating a Cut-Off
Most popular sources will proclaim that anything over a 2 finger-width gap between the rectus abdominis is a diastasis recti. I say the same thing in What is Diastasis Recti? After reading some of the studies, I’d say that’s still a good shorthand, keeping in mind that finger sizes differ and how far you lift your head will also affect the size (the higher you go, the more the rectus abdominis is engaged, the smaller the gap). This doesn’t mean that anything over 2 finger-widths is cause for immediate worry, but it does mean you are venturing into outside “normal” territory. I hung out at about 3 finger-widths for a long time with no problems, so it’s not that big of a deal for many women. Over time, it got smaller and now I’m technically “normal,” but I still have a mushy belly that sticks out some, so DR size isn’t the only thing that creates a postpartum tummy.
Why do I stand by my 2 finger-width measurement? Because it mostly jibes with the studies. A longitudinal study in Musculoskeletal Science and Practice sought to answer the “what is normal” question by measuring inter-recti distance (IRD) in women during the third trimester of pregnancy and then at approximately 6, 12, and 24 weeks postpartum. The measurements were made via ultrasound.
This study showed that the IRD distance varied among women (naturally) but also at different sites of measurement, with the greatest inter-recti distance 2 cm above the belly button and the lowest 2 cm below; this totally coincides with my own experience obsessively measuring my DR. They noted that the average IRD was larger post-pregnancy than in nulliparous women, as measured in previous studies. In other words, when defining DR, don’t look at women who’ve never had babies as the norm.
I made some simple graphs comparing the measurements in this study with the measurements of nulliparous women (from another study that also used ultrasound) to give a rudimentary visual of the max “normal” IRD in nulliparous, pregnant, and postpartum women. These charts are extremely rough because the studies measured in different spots and the longitudinal study didn’t measure at the belly button. But, if you are obsessing about whether you have a DR, the charts might provide some perspective.
Both charts show the same data btw. “Above” and “below” refers to above or below the belly button.
The actual numbers in the charts are the following:
Nulliparous 3 cm above belly button: 22 mm
Nulliparous 2 cm below belly button: 16 mm
Pregnant 2 cm above belly button: 86 mm
Pregnant 2 cm below belly button: 79 mm
6 Months Postpartum 2 cm above belly button: 28 mm
6 Months Postpartum 2 cm below belly button: 21 mm
As a reference point, two of my fingers measure about 26 mm (my fingers are very small though), so this is why I think the 2 finger-widths is a usable, albeit crude, way to make preliminary measurements.
Do not take these numbers as the final word! Breaking out a ruler and trying to figure out the millimeter size of your gap 2 centimeters above your belly button is not going to be helpful. It’s also hard to do by yourself (Don’t ask me how I know). Also, if your gap measures 2.5 finger-widths don’t assume this means, gasp, you are broken. But if you can fit a lot of fingers between your rectus, say 3 or more, you are venturing into deeper DR territory. Then again, not being normal doesn’t mean you are pathological. Make sense?
If you have an IRD that is outside the max ranges from these studies, what can you do to make it smaller? This is the million dollar question! The question that so many people claim to have answered definitively. But, alas, they probably haven’t. I’ll talk about this in a later post. (Subscribe to the newsletter if you want to receive posts by email, or if you are desperate for (non)answers now, check out this essay.)
In the meantime, keep working out smartly, which means paying especial attention to a weak abdomen by making sure an exercise doesn’t balloon your stomach, a sign that you are exerting more intra-abdominal pressure than you can safely manage. I know that advice is boring and doesn’t promise anything, but boring is okay with me. Oh, and if you are one of those women with a one finger-width gap, you don’t have diastasis recti. You might have other problems, but DR ain’t one of them, no matter what the internet says.