The human pelvis is a structure of bones designed to support the upper body and facilitate movement. At the front of the pelvis, the two pubic bones are joined by a piece of fibrocartilage, creating a joint known as the pubic symphysis. During pregnancy, hormonal changes cause this joint and its connecting ligaments to soften and widen to prepare for childbirth. In a non-pregnant state, the gap is 4 to 5 millimeters, and this can increase by another 2 to 3 millimeters during gestation.
Pubic symphysis diastasis occurs when this separation becomes excessive. This over-separation transforms a normal physiological process into a source of pain and instability, impacting mobility and quality of life. The condition is distinct from the more common pelvic girdle pain, as diastasis involves a measurable dislocation of the joint itself.
Causes and Risk Factors
The development of pubic symphysis diastasis is rooted in a combination of hormonal and mechanical factors that exert pressure on the pelvis. The primary hormonal driver is relaxin, a hormone produced early in gestation. Working alongside progesterone, relaxin increases the laxity of pelvic ligaments, softening the pubic symphysis to create more space for delivery. This hormonal softening, while beneficial for birth, makes the joint inherently less stable and more susceptible to injury.
This ligamentous laxity is then compounded by mechanical forces. The increasing weight of the growing fetus places downward pressure on the pelvic girdle throughout the pregnancy. During labor, this pressure intensifies as the baby’s head descends and engages with the pelvis. A rapid second stage of labor, severe abduction of the thighs, or the use of instruments like forceps can also apply traumatic force directly to the joint.
Certain individuals are at a higher risk of developing this condition.
- Macrosomia, which refers to delivering a baby that is significantly larger than average, as this increases the mechanical strain on the pelvis.
- Multiparity, meaning they have had multiple pregnancies, may also be more vulnerable as their ligaments may have been repeatedly stretched.
- Pre-existing pelvic misalignments or a history of pelvic injury can predispose the joint to excessive separation.
- The use of epidural anesthesia is also considered a risk factor, as it can diminish the mother’s ability to sense and react to damaging movements during labor.
Recognizing the Symptoms
The symptoms of pubic symphysis diastasis are centered around pain and functional impairment. The main symptom is sharp, stabbing, or shooting pain located directly over the pubic bone at the front of the pelvis. This pain frequently radiates outwards to the groin, inner thighs, lower back, and perineum. The intensity can range from a nagging discomfort to severe pain that significantly restricts movement.
Beyond the pain, a defining characteristic of the condition is a sensation of pelvic instability. Many individuals report hearing or feeling an audible clicking, popping, or grinding sound from their pelvis during movement. This sensation is often accompanied by a “waddling” gait, as the body alters its walking pattern to minimize painful motion and compensate for the lack of stability.
These symptoms are exacerbated by specific activities that place asymmetrical loads on the pelvis. Actions that require lifting one leg at a time, such as climbing stairs, getting in and out of a car, or turning over in bed, can become painful. The difficulty with these everyday movements underscores the functional impact of the joint separation.
Diagnosis and Treatment Approaches
The diagnostic process for pubic symphysis diastasis begins with a physical examination. A healthcare provider will inquire about the specific nature and location of the pain, as well as any functional difficulties. During the physical assessment, the provider may palpate the pubic symphysis to check for tenderness and a palpable gap. Specific maneuvers, like having the patient stand on one leg, can be used to assess the instability of the joint.
To confirm the diagnosis and quantify the extent of the separation, imaging studies are used. A standard anteroposterior (AP) X-ray of the pelvis is a common method used to visualize the pubic symphysis and measure the distance between the bones. An ultrasound can also be used, offering a non-radiation alternative to assess the joint space. A separation greater than 10 millimeters on these images is considered diagnostic for pubic symphysis diastasis.
Most cases are managed effectively with conservative, non-surgical treatments. The initial focus is on rest and pain management, which may include applying ice packs to the affected area and using prescribed analgesics. A primary component of conservative care is the use of a pelvic support belt or binder. These devices work by providing external compression to the pelvis, squeezing the bones closer together to promote stability and reduce pain.
Specialized physical therapy is another component of treatment. Surgical intervention is rarely needed and is reserved for cases involving extreme separation and persistent instability that do not respond to months of conservative management.
Recovery and Management Strategies
The recovery period for pubic symphysis diastasis varies, but most individuals see significant improvement within several weeks to a few months postpartum. The healing process is gradual and requires adherence to specific management strategies designed to protect the joint from further strain. The primary goal is to allow the stretched ligaments to heal and shorten while building muscular support around the pelvis.
Daily life must often be modified to minimize pain and prevent re-injury. A key technique is “log rolling” in bed—keeping the knees and shoulders aligned and moving the entire torso as a single unit to avoid twisting the pelvis. When getting in or out of a car, it is advised to keep the knees together and pivot on the buttocks. Activities that place stress on the pelvis, such as heavy lifting or prolonged standing, should be avoided.
Physical therapy plays a large role in long-term recovery and management. The exercises prescribed are highly specific to strengthen the transverse abdominis, multifidus, pelvic floor, and hip muscles. Strengthening this network of muscles creates a “natural corset” that actively pulls the pelvic bones together, providing dynamic stability to compensate for the ligamentous laxity. This targeted muscle re-education is what ultimately restores function and helps prevent future episodes of pelvic pain.