Core Dysfunction Series Part II: Causes of Diastasis Recti in Pregnancy and the Postpartum

Continuing our core dysfunction series with diastasis recti.  In Part I of this series we defined diastasis recti as the separation of the two halves of the rectus abdominus (six pack muscles) and noted that nearly 100% of pregnant women will develop diastasis.  It is a normal part of pregnancy, as our abdominal cavity needs to make room for a growing baby!  As a reminder, these blog posts are not medical advice and are for educational purposes only.  We recommend that you consult your medical practitioner or pelvic floor physical therapist for any concerns that you may have. 

Causes of Diastasis Recti During Pregnancy & What May Be Preventing Healing in the Postpartum

While there are a multitude of things that may cause diastasis, we are going to highlight three main factors that Mama has control over (mostly at least): Posture, Breathing, and Activity.  In the next blog post, we will discuss how to use these three categories to heal in the postpartum. 

There are other factors that Mama might not have control over, such as genetics or physical and emotional support during pregnancy or the postpartum. However, we will not touch upon those in this post. 

While the following three factors might not seem to be directly related to diastasis, we need to remember that diastasis is a symptom for a bigger problem, not necessarily the problem itself. 

1. Posture

As pregnancy progresses, there is an increased weight on our front side (belly & breasts).  This increased front load tends to contribute towards less effective posture and may be forcing your body to compensate to remain upright.  These compensations can prevent proper healing and potentially encourage poor pressure management strategies for the abdominal cavity. 

So, what are less effective postures that usually occur during pregnancy?

  • Sway back position

  • Rib thrust & pelvic anterior tilt

  • Increased lumbar spine curvature

  • Forward head position & round of the upper back

  • Decreased mobility of the thoracic

Sway Back Position: Posterior Tilt of the Pelvis, Ribs pushed backwards. Common position for resting or holding babies, as it is easier to collapse into joints than to support with muscles.

Sway Back Position: Posterior Tilt of the Pelvis, Ribs pushed backwards. Common position for resting or holding babies, as it is easier to collapse into joints than to support with muscles.

Rib thrust posture: Pelvis is usually tilted forward, and ribs lift upwards. Increases distance between ribs and pelvis, and aggravates the linea alba.

Rib thrust posture: Pelvis is usually tilted forward, and ribs lift upwards. Increases distance between ribs and pelvis, and aggravates the linea alba.

Forward Head & Rounded Upper Back Posture: Head is pushed forward, lengthening in the back of the neck and shoulders. Ribs sometimes pushed downwards.

Forward Head & Rounded Upper Back Posture: Head is pushed forward, lengthening in the back of the neck and shoulders. Ribs sometimes pushed downwards.


Think of posture as the foundation for our home; if the foundation is off, then everything we build from there will be off as well. 

Now regarding diastasis, the linea alba (connective tissue between our six pack abs) runs vertically along our torso.  The more our ribs and pelvis are misaligned in poor posture (particularly in postures where the distance between the front of the ribs and front of the pelvis is increased, such as ribs thrusted upwards and pelvis tilted forward), the more aggravated this tissue becomes and the harder it must work to help stabilize.  This is all compounded once you add the mandatory stretching that the linea alba must already do to allow your baby to grow! 

2. Breathing

Breathing is the next step toward stabilization in our core, and poor breathing patterns can be a cause of diastasis. 

As pregnancy progresses, the diaphragm’s movement is restricted, and can lead to poor breathing patterns.  Two prevalent poor breathing habits that may occur are:

  • Chest Breathing

  • Belly Breathing

During chest breathing, the chest rises upwards during an inhale and drops during an exhale.  This utilizes secondary breathing muscles (think of all the muscles in your upper chest, shoulders, and neck that now must work to lift your chest up to take an inhale) and can cause a ripple effect towards causing poor postural habits and movement patterns. 

During belly breathing, only the belly expands forward during inhales.  This comes back to the same principle that, the greater the distance between the ribs and the pelvis, the more aggravated the linea alba will become.  This breathing pattern is also a pressure management issue. 

During an inhale, the pressure within the abdominal cavity increases.  This increase in pressure is due to the decrease in volume caused by the diaphragm moving downwards during an inhale.

If the abdominal wall and pelvic floor cannot manage pressure, that pressure will leak out somewhere.  Examples of pressure leakage include: through the linea alba with diastasis; a hernia; or even prolapse in the pelvic floor.  A poor pressure management strategy could contribute to persistent diastasis in the postpartum or even an in increase in symptoms and severity during pregnancy.          

3. Activity

Exercise during pregnancy can help Mama adapt to postural changes, relieve aches and pains, and ultimately meet the demands of labor!  It is so necessary for a prenatal Mama and her growing baby. Not all exercises are created equal when it comes to pregnancy, and some exercises should even be avoided all together during pregnancy and the early postpartum.

As pregnancy progresses, three out of the four major muscles of the core’s function are affected: the diaphragm is restricted; the transverse abdominals are stretched; and the pelvic floor takes on an additional load.  Since the core is already in such a compromised state during pregnancy, it is crucial to approach fitness with alignment and breath in mind.

Exercises that bring Mama out of alignment over and over again will continue to aggravate her linea alba and potentially contribute towards a more severe diastasis and prevent it from healing properly or altogether in the postpartum. 

Activities such as; kipping pull ups, sit ups, isolated core movements, or movements that involve excessive flexion or extension of the spine may contribute towards issues with diastasis. 

There is not a list of “good” and “bad” movements that we can offer you because it matters more HOW you do the movement rather than WHAT the movement is. 

Movements that you can perform while in optimal positioning which utilize a great breathing and pressure management strategy, feel good during and after, are great movements to engage in during pregnancy and the postpartum.  If you cannot maintain optimal positioning, the pressure cannot be managed, and/or once the movement is uncomfortable or causes pain then it is time to reevaluate the movement and determine if we need to modify or omit it all together. 

In our small group training, it is not uncommon to have two Mamas in the exact same week of pregnancy who must take different variations of the same workout. 

For example, the workout may have rowing listed in the conditioning.  Mama A still can manage the pressure in the abdominal cavity, and experiences no coning, while Mama B has reached a point in her pregnancy when rowing is no longer comfortable, and she experiences coning during rowing.  In the latter situation, we would remember what the goal of the movement is (in this instance it is cardio), and progress towards another movement that Mama can utilize to meet the same intent but have no symptoms of coning. 

The controllable factors which can contribute towards diastasis recti and prevent healing in the postpartum are: Posture, Breathing, and Activity.  Optimal positioning, a great breathing pattern/pressure management strategy, and appropriate movements are all key towards helping a prenatal or postpartum Mama navigate their motherhood journey without dysfunction in their bodies.