During pregnancy the linea alba, a vertical line of connective tissue which runs from the base of the sternum to the pubic bone and separates the left and right Rectus abdominis muscles ("six-pack muscles") becomes "stretched” to accommodate the growth of the fetus and supporting structures. This is a NORMAL adaptation to pregnancy with the literature having found that 27-100% of women exhibit a Diastasis Recti Abdominis (DRA) during the middle and late stages of pregnancy respectively. (1) According to the literature at 6 weeks postpartum the prevalence of DRA is 60% with ~33% of women still exhibiting a DRA at 12 months postpartum. (2) So to summarize, DRA is a NORMAL adaptation during pregnancy and commonly persists during the postpartum period.
But, what if I was to tell you that Diastasis Recti Abdominis postpartum may actually be protective in nature and your body's way of protecting the pelvic floor postpartum while it heals?
Myth-Busting Diastasis Recti Abdominis
Per the literature, there is NO DIFFERENCE in reported low back pain in women with and without DRA 12 months postpartum. (2, 3) At this time, with the research we have available, we cannot definitively show causation with regards to the simultaneous presence of DRA and low back pain or even stress urinary incontinence. (4) Additionally, there has been no difference in the occurrence of urinary incontinence and pelvic organ prolapse (POP) when comparing those women with and without a DRA postpartum, even when taking into consideration the severity, or width, of the DRA. (1)
Now for the mind blowing...
Diastasis Recti Abdominis (DRA) may not only be null-in-void, but may actually be PROTECTIVE during the postpartum period. At this time there has been more and more literature that has been coming out that has been showing that a DRA postpartum may actually help to reduce the incidence and severity of pelvic organ prolapse (POP) and stress urinary incontinence.
The Proposed Physiological Mechanism Behind the Protective Nature of a Diastasis Recti Abdominis Postpartum
To answer this question, first you must understand the anatomy of the inner core musculature and how the coordination and use of these muscles influence intra-abdominal pressure management and secondarily pressure generation.
You may have either tried this before or seen someone else attempt to do it – The contents of a soda can are non-compressible if you attempt to do so when the can is full and sealed. This is secondary to the amount of pressure within the can, with the external pressure needing to be greater than the internal pressure to successfully crush the can.
This same analogy can be applied to the inner core musculature and the content of the abdominopelvic region. As shown in the picture to the left (5), the inner core muscles make up a cylindrical structure similar to the aluminum structure of a soda can with the pelvic floor the ‘base’ of the can and the respiratory diaphragm the ‘top’ of the can.
When you inhale or bear down (as shown below), your diaphragm contracts and “flattens” thus increasing pressure within the abdominal cavity and causing the pelvic floor muscles to descend or “lengthen”.
During a vaginal delivery the muscles of the pelvic floor are stretched up to 3X THEIR RESTING LENGTH. Not taking into consideration any potential complications, the recovery time frame of the pelvic floor muscles is believed to be 4-6 months postpartum. During this time it may be advantageous to reduce strain through the pelvic floor musculature to help optimize healing. One way in which the body may inherently do this is by temporarily lengthening the abdominal wall (picture on the left above) to allow for greater dispersion of pressure with increases in intra-abdominal pressure to thus reduce strain on the pelvic floor. And, do want to know one way the body inherently "lengthens" the abdominal wall during pregnancy and postpartum... A Diastasis Recti Abdominis!
So what does all of this mean?
Pregnancy and postpartum can be a beautiful time during one’s life but can also be a time with associated fear of the unknown as your body physiologically changes to accommodate the growth of your unborn child. No matter if you are pregnant, immediately postpartum or 5+ years postpartum do not let this fear overcome you! Most of these anatomical adaptations are a normal part of the pregnancy and postpartum experience but a pelvic physical therapist has the knowledge, education and experience to educate you regarding your body and most importantly help you take back control of your body and your life!
References:
Fei, H., Liu, Y., Li, M. et al. The relationship of severity in diastasis recti abdominis and pelvic floor dysfunction: a retrospective cohort study. BMC Women's Health 21, 68 (2021). https://doi.org/10.1186/s12905-021-01194-8
Goom, T., Donnelly, G. and Brockwell, E. (2019) Returning to running postnatal – guideline for medical, health and fitness professionals managing this population. [https://mailchi.mp/38feb9423b2d/returning-to-running-postnatal-guideline]
Sperstad, J. B., Tennfjord, M. K., Hilde, G., Ellström-Engh, M., & Bø, K. (2016). Diastasis recti abdominis during pregnancy and 12 months after childbirth: Prevalence, risk factors and report of Lumbopelvic Pain. British Journal of Sports Medicine, 50(17), 1092–1096. https://doi.org/10.1136/bjsports-2016-096065
Braga, A., Caccia, G., Nasi, I., Ruggeri, G., Di Dedda, M. C., Lamberti, G., Salvatore, S., Papadia, A., & Serati, M. (2020). Diastasis recti abdominis after childbirth: Is it a predictor of stress urinary incontinence? Journal of Gynecology Obstetrics and Human Reproduction, 49(10), 101657. https://doi.org/10.1016/j.jogoh.2019.101657
Massery M. Musculoskeletal and neuromuscular interventions: a physical approach to cystic fibrosis. J R Soc Med. 2005;98 Suppl 45(Suppl 45):55-66. PMID: 16025768; PMCID: PMC1308809.