During pregnancy and the postpartum period, many women suffer from both functional and cosmetic issues caused from the widening of the abdominal wall from stretch and pressure generated from the growing uterus. This stretching can result in a separation of the rectus abdominis muscle, known as a diastasis recti (DR). Diastasis recti occur in approximately 66% of women in their third trimester of pregnancy 1, many of which continue to suffer even 1-year postpartum, despite physical therapy or exercise programs designed to close this gap. In addition to the pregnant/postpartum population, others can suffer from this as well, including athletes, babies, and even patients who have undergone laparoscopic surgery such as hysterectomy, endometriosis, and prostatectomy.
Malinda wrote a great blog all about DR that you can read here that discusses functional limitations a DR could impose, how to check for it, and some basics on how to close it. This blog will focus on the ongoing debate of what researchers and clinicians believe is the best way to rehabilitate diastasis recti.
Is it really important that there is a wider gap than before pregnancy or surgery? Should we focus on crunches, abdominal bracing, or surgery? What should be done when exercise is not enough? And ultimately, how does one know when someone may require surgical intervention?
Anatomy of diastasis recti
The rectus abdominis is what we commonly think of as our six-pack muscle that connects from our sternum all the way to our pubic bone. We have two of them, one on the right and one on the left, that are separated by a dense band of connective tissue known as the linea alba. The linea alba is made from a continuation of our internal obliques, external obliques, and the transverse abdominal muscles.
What is the function of our abdominal muscles?
The function of the abdominal musculature is to resist changes in intra-abdominal pressure (IAP), and transfer forces between our right and left sides during movement such as lifting our legs, twisting, etc. When there is a widening of these muscles and the linea alba becomes lax, we lose this ability, and it is possible that we may experience low back pain, weakness, pelvic girdle pain, urinary incontinence, and in time, even pelvic organ prolapse may occur.
What is normal?
In general, there is debate about how wide the inter-rectus distance (IRD) can be, and researchers have performed imaging in cadavers, as well as in women who have not had children (nulliparous), to determine what is “normal.” How wide and at which points to measure vary in the literature, and currently there is no international consensus in the best way to measure. Most recently, there was a study performed on nulliparous women that suggested a normal linea alba should be less than 15mm at the xiphoid level, 33mm at 3 cm above the umbilicus and 16mm at 2 cm below the umbilicus.3
Most physical therapists, trainers, and exercise programs that currently exist tend to focus on closing the gap between the rectus abdominis muscle bellies. At PHRC and many other clinics, we teach patients to pull the bellybutton to the spine (a draw-in maneuver that activates our transverse abdominis muscle also called a TrA contraction) and then with a towel wrapped around the widest part of the gap, do a mini abdominal crunch which activates the rectus abdominis muscle bellies and pulls them closer together. It has generally been thought that the TrA contraction will draw the muscle bellies of the rectus abdominis together and improve stability of the core, while abdominal crunches alone have been considered a risk for the development of DR. 4
There was a recent journal article released from the Journal of Orthopedic and Sport Physical Therapy (JOSPT) that actually looked at the effect of a drawing-in maneuver (or TrA contraction) and the abdominal crunch in its ability to decrease the IRD. Surprisingly, it showed that doing a draw-in maneuver caused a slight widening of the IRD, while the abdominal crunch in both the gestational period (during pregnancy) and postpartum periods showed a narrowing of the IRD 2 – which has been the focus of rehab!
This was interesting because like I said before, abdominal crunches tend to not be the exercise of choice and have been thought to be a risk factor for DR. This also led to the question – does closing the gap really matter as much as we previously thought?
Technically, we do not just have patients do a draw-in maneuver, nor do we have them just do crunches or sit ups to correct the DR, we actually teach them a very specific way to do this correction exercise, and it involves a combination of the two exercises. In a very recent study by Diane Lee and Paul Hodges, they did look at what happens at the IRD with an abdominal crunch alone, and an abdominal crunch with pre-activation of the transverse abdominis muscle or a “draw-in” maneuver. What they found was that doing a draw-in maneuver with a crunch decreased the narrowing of the IRD compared to what would occur with an abdominal crunch alone. This still technically does not close the DR as well as we’d like, but it does increase the tension on the linea alba, which they propose is necessary to support the abdominal contents and to transfer force between the two sides of the abdominal wall.5
Currently, the goal of rehabilitating a DR is to reduce the IRD. This is based on the assumption that closing the gap will restore the function of the core and improve cosmetic appearance. Lee and Hodges showed the opposite in their study, and demonstrated that while we are closing the gap, we are creating more laxity or distortion on the linea alba, which makes us less likely to restore the function of our abdominal wall; this will lead to potentially poorer cosmesis of the abdominal wall.
What to do now?
It seems that closing the gap may not matter as much as we previously thought, and instead of focusing on the width of the gap, we should be focusing on optimizing the functional ability of our abdominal wall to generate enough tension to stabilize us in order to perform the activities we do on a regular basis and this will vary individually.
If you suffer from a DR and have not been assessed by a physical therapist, start there! During their evaluation, the physical therapist will be able to identify functional and structural impairments that may be contributing to ongoing symptoms, and can either help you to continue to improve your function, or have the resources to refer you to a surgeon if conservative approaches have been exhausted.
Below is a list of criteria that would identify a good surgical candidate, your physical therapist can help determine if you would benefit from a surgical consult. To find out more about pregnancy and postpartum physical therapy, visit our website or our Pinterest page.
Who actually needs surgical intervention?
According to Dianne Lee, the criteria for referral to a surgeon are summarized below:
- The woman should be at least 1 year postpartum and has failed appropriate therapeutic approaches to restore function, resolve lumbopelvic pain and/or urinary incontinence.
- The inter-recti distance is greater than mean values, and the abdominal contents are easily palpated through the midline fascia.
- Multiple vertical loading tasks reveal failed load transfer through the lumbopelvis.
- The active straight leg raise test is positive, and the effort to lift the leg improves with both approximation of the pelvis anteriorly, as well as approximation of the lateral fascial edges of rectus abdominis.
- The articular system tests for passive integrity of the joint of the low back and/or pelvis (mobility and stability) are normal.
- Diastasis Rectus Abdominis & Postpartum Health Consideration for Exercise training: http://dianelee.ca/article-diastasis-rectus-abdominis.php
- Mota P, Pascoal AG, Carita AI, Bo K. The immediate effects on inter-rectus difference of abdominal crunch and drawing-in exercises and during pregnancy and the postpartum period. J Orthop Sport PhysTher. 2015; 45(10):781-788.
- Beer GM, Schuster A, Seifert B, Manestar M, Mihic-Probst D, Weber SA. The normal width of the linea alba in nulliparous women. Clin Anat. 2009;22:706-711. http://dx.doi.org/10.1002/ ca.20836
- Blanchard PD. Diastasis recti abdominis in HIV-infected men with lipodystrophy. HIV Med. 2005;6:54-56. http://dx.doi. org/10.1111/j.1468-1293.2005.00264.x
- Lee D, Hodges PW. Behavior of the linea alba during a curl-up task in diastasis rectus abdominis: an observational study. J Orthop Sports Phys Ther. 2016;46(7):580-589.