Causes of Diastasis Recti Abdominis
Diastasis recti abdominis results from weakening and stretching of the linea alba due to increased intraabdominal pressure, hormonal changes during pregnancy, obesity, aging, and impaired motor control of the transversus abdominis muscle.
Primary Etiological Factors
Pregnancy-Related Causes
Pregnancy remains the most well-documented cause, though it is not the sole mechanism. During pregnancy, hormonal changes cause ligament relaxation and the growing uterus creates sustained intraabdominal pressure that stretches the linea alba 1. Multiple pregnancies increase risk substantially 2. However, the evidence clearly shows this is not exclusively a postpartum condition—diastasis recti affects men and nulliparous women at similar rates when other risk factors are present 3.
Increased Intraabdominal Pressure
Any condition causing chronic elevation of intraabdominal pressure can lead to diastasis recti 4. This includes:
- Obesity and visceral adiposity (particularly significant in males) 5, 2
- Chronic cough or respiratory conditions
- Heavy lifting with poor core mechanics
- Ascites or abdominal masses
Age-Related Degeneration
Aging independently contributes to diastasis recti through progressive weakening of the linea alba collagen structure 6. In males, prevalence increases significantly after age 60, with reported rates of 25-30% 5, 7. The quality of linea alba deteriorates with fewer intercrossing fibers 5.
Impaired Motor Control
A critical and underappreciated mechanism: impaired motor control of the transversus abdominis muscle appears to be a primary causative factor, not merely a consequence 3. This study of 849 back pain patients found no gender difference in inter-rectus distance above the umbilicus (45% of women vs 43% of men), suggesting motor control dysfunction rather than pregnancy alone drives pathology 3.
Metabolic and Systemic Factors
- Diabetes mellitus is an independent risk factor, particularly in younger women 2
- Smoking adversely affects linea alba quality 5
- Menopausal hormonal changes increase susceptibility 6
Clinical Pitfalls to Avoid
Do not assume diastasis recti is purely a postpartum cosmetic issue—this outdated view misses the functional implications and male prevalence. The condition causes core instability, low back pain (highly significant association 2), and when severe, can impair quality of life 6.
In males presenting with ventral hernias, always assess for concomitant diastasis recti—47% have other abdominal wall hernias and 67% with aortic aneurysm have diastasis recti 5. Yet only 4-14% of affected males receive treatment, suggesting massive underdiagnosis 5.
Risk Stratification
Young women (<30 years): Pregnancy is the dominant risk factor, with twice the incidence compared to young men 3
Women and men >30 years: No gender difference in prevalence; focus on obesity, diabetes, smoking, and core dysfunction 3, 2
Males specifically: Visceral obesity, aging, low physical activity, and smoking are primary drivers 5, 7
The evidence demonstrates that continuing aerobic exercise like walking during pregnancy decreases odds of developing diastasis recti, while abdominal strengthening exercises (e.g., abdominal curls) should be avoided as they worsen the condition 1.