The stretching of the abdomen during pregnancy often causes diastasis recti (DR), the separation of the main vertical abdominal muscles. This condition occurs when the rectus abdominis muscles, commonly called the “six-pack” muscles, pull apart from the midline connective tissue. Diastasis recti is a common occurrence that allows the abdominal wall to expand to accommodate a growing fetus. Understanding the prevalence and risk factors associated with this separation is important for those affected.
Defining and Measuring Diastasis Recti
Diastasis recti is characterized by the widening of the linea alba, the fibrous structure connecting the two sides of the rectus abdominis muscles. Hormonal changes during pregnancy soften this connective tissue, making it more elastic and prone to stretching under the pressure of the expanding uterus. The separation is diagnosed by measuring the inter-rectus distance (IRD) at various points along the midline.
A clinical diagnosis is generally made when the separation measures 2 centimeters or greater, or approximately two finger-widths, at the umbilical level. Measurement is typically performed by a healthcare provider using palpation, or with tools like ultrasound or calipers. While the 2 cm criterion is widely accepted, the distance considered abnormal can vary depending on the measurement location, the patient’s gender, and the time elapsed since delivery.
Statistical Prevalence Across Populations
Diastasis recti is a frequent condition in the pregnant and postpartum population, with prevalence rates changing significantly over time. During the third trimester of pregnancy, the condition is nearly universal; studies report that 82.5% to 100% of women experience some degree of separation by the 35th week. This high rate reflects the physical accommodation the body makes for the fetus.
The prevalence begins to drop in the immediate postpartum period as the body recovers and the uterus shrinks. Within six weeks after childbirth, approximately 60% of new mothers still meet the criteria for diastasis recti. This natural resolution continues over the next several months.
By six months postpartum, the prevalence typically falls to a range between 39% and 45.5%. Studies tracking women for a full year show that the separation persists in about 32.6% to 33% of new mothers. Although most commonly associated with pregnancy, DR can also affect premature newborns and men who experience excessive abdominal strain, such as from heavy weightlifting or chronic coughing.
Key Factors Increasing Susceptibility
Several factors can increase the likelihood of developing a separation that persists after childbirth. One prominent factor is multiparity, meaning a woman has had multiple pregnancies, as the abdominal wall is repeatedly stretched and weakened. Similarly, carrying multiples, such as twins or triplets, places a greater strain on the abdominal wall due to increased fetal size and volume.
Advanced maternal age, often cited as over 35 or 38, is also associated with greater susceptibility. The elasticity of connective tissues naturally decreases with age, making the linea alba less capable of fully recovering its tension. Other physical factors include large fetal size, which maximizes outward pressure, and a genetic predisposition related to collagen strength and structure.
Activities that create high intra-abdominal pressure can also contribute to the condition. This includes chronic, forceful actions like heavy lifting, strenuous abdominal exercises, and chronic coughing or straining. Obesity and a lack of pre-pregnancy core strength can also contribute to the pressure and overall weakness of the supporting abdominal muscles.
Next Steps After Diagnosis
If a separation is suspected, the first step is to seek a professional assessment to confirm the diagnosis and severity. Consulting a pelvic floor physical therapist or a healthcare provider is the most appropriate action. These specialists can determine the exact width and depth of the gap and assess the functional stability of the core.
Management of diastasis recti often involves a targeted rehabilitation program focused on restoring core function. This specialized approach aims to strengthen the deep core muscles without exacerbating the separation. Patients are typically advised to avoid traditional, high-pressure abdominal exercises, such as crunches or sit-ups, which can worsen the condition.