Sacroiliac Pain in Pregnancy: Causes and Treatment

Title: Sacroiliac Pain in Pregnancy: Hormonal, Biomechanical Causes and Physiotherapy

Frequently Asked Questions

What is sacroiliac pain in pregnancy?

Sacroiliac pain in pregnancy is a common condition affecting 20-45% of pregnant women, causing debilitating symptoms in the posterior pelvic region. It typically localizes around the sacroiliac joints and can radiate to the buttocks and thighs, impacting quality of life and mobility.

What causes sacroiliac pain during pregnancy?

Sacroiliac pain in pregnancy is multifactorial, primarily due to hormonal changes and biomechanical alterations. Hormones like relaxin increase ligament laxity in the pelvis, reducing the stability of the sacroiliac joint. This forces surrounding muscles to overcompensate, often leading to pain.

How does the sacroiliac joint normally function?

The sacroiliac joint connects the sacrum to the iliac bones, primarily providing stability and transmitting loads from the trunk to the lower limbs. Its stability relies on ‘form closure’ from its irregular shape and strong ligaments, and ‘force closure’ from the synergistic contraction of surrounding muscles.

What are the common symptoms of sacroiliac pain in pregnancy?

Symptoms typically include pain in the posterior pelvic region, specifically corresponding to the sacroiliac joints. This pain can radiate towards the buttocks and the posterior portion of the thighs, potentially compromising a pregnant woman’s quality of life, mobility, and work capacity.

What should I do if I experience sacroiliac pain during pregnancy?

It is essential to consult your doctor or a physical therapist if you experience symptoms of sacroiliac pain during pregnancy. They can provide an accurate diagnostic assessment, rule out any strictly obstetric or medical conditions, and develop an appropriate, evidence-based treatment plan.

Sacroiliac pain in pregnancy represents one of the most frequent and debilitating clinical manifestations affecting the musculoskeletal system during the gestational period. This condition, often framed within the broader spectrum of Pelvic Girdle Pain (PGP), affects a significant percentage of women, with estimates varying from 20% to 45% depending on epidemiological studies (Kanakaris et al., 2011). The symptomatology typically localizes in the posterior region of the pelvis, corresponding to the sacroiliac joints, and can radiate towards the buttocks and the posterior portion of the thighs, severely compromising the pregnant woman’s quality of life, mobility, and work capacity. The management of this problem requires a multidisciplinary and evidence-based approach. It is essential to emphasize that, should such symptoms appear, it is always necessary to consult your doctor or physical therapist for an accurate diagnostic assessment and to rule out any strictly obstetric or medical conditions.

Anatomy and Biomechanics of the Sacroiliac Joint

Sacroiliac pain in pregnancy is a common musculoskeletal condition affecting 20-45% of pregnant women, characterized by posterior pelvic pain at the sacroiliac joints that may radiate to the buttocks and thighs. To fully understand the pathological dynamics that lead to the development of painful symptoms, it is essential to analyze the anatomy and biomechanics of the pelvis. The sacroiliac joint (SIJ) is an atypical diarthrodial joint that connects the sacrum to the iliac bones. Its primary function is not mobility, but rather stability and the transmission of loads from the trunk to the lower limbs.

The articular surfaces are characterized by an irregular conformation, with complementary ridges and depressions that ensure a mechanical interlocking defined as “form closure”. This intrinsic stability is further reinforced by a complex ligamentous apparatus, among the most robust in the human body, which includes the anterior, interosseous, and posterior sacroiliac ligaments, as well as the sacrotuberous and sacrospinous ligaments (Vleeming et al., 2012).

In addition to form closure, joint stability is ensured by “force closure”, a dynamic mechanism generated by the synergistic contraction of the surrounding musculature and fascial tension. The muscles primarily involved in this active stabilization system include the transversus abdominis, lumbar multifidus, pelvic floor muscles, gluteus maximus, and biceps femoris. During gestation, alterations in these two closure systems represent the primary pathophysiological substrate for the onset of pain.

Causes of sacroiliac pain in pregnancy

The etiology of sacroiliac pain in pregnancy is multifactorial and results from a complex interaction between endocrine modifications, biomechanical alterations, and postural adaptations that physiologically occur to accommodate fetal development and prepare the body for childbirth.

Hormonal Factors

From an endocrine perspective, pregnancy is characterized by a massive release of hormones, including progesterone, estrogen, and, in particular, relaxin. Relaxin, produced by the corpus luteum and placenta, has the specific task of remodeling collagen, inducing greater laxity of the pelvic ligaments and pubic symphysis (Wu et al., 2004). While this process is essential to facilitate the passage of the fetus through the birth canal, the increase in ligamentous laxity compromises the “form closure” of the sacroiliac joint. The reduction in passive stability forces the neuromuscular system to overwork to maintain “force closure”, often leading to muscle overload, spasms, and nociceptive pain resulting from the stretching of the joint capsules and ligaments themselves.

Biomechanical and Postural Factors

Parallel to hormonal changes, uterine growth induces drastic biomechanical changes. The increase in abdominal volume and weight shifts the body’s center of gravity forward and upward. To compensate for this shift and maintain balance, the pregnant woman physiologically adopts a posture characterized by an increase in lumbar lordosis and pelvic anteversion (Franklin & Conner-Kerr, 1998).

This new postural configuration alters the force vectors acting on the sacroiliac joint. Pelvic anteversion increases shear stress on the sacroiliac articular surfaces. Furthermore, the distension of the abdominal musculature (particularly the rectus abdominis and transversus abdominis) reduces its contractile efficiency, further compromising the dynamic stability of the pelvis. The overload consequently transfers to the posterior musculature (spinal erectors, quadratus lumborum, piriformis), which experiences hypertonicity and chronic fatigue.

Risk Factors and Occupational Impact: INAIL Data

The onset of symptoms does not affect all pregnant women equally. Scientific literature has identified several predisposing risk factors, including a history of low back or pelvic pain, previous pelvic trauma, generalized joint hypermobility, high pre-pregnancy body mass index (BMI), and multiparity (Albert et al., 2006).

A fundamentally important, often underestimated, aspect is the impact of work activity. According to INAIL (National Institute for Insurance against Accidents at Work) data and guidelines regarding the protection of working mothers (Legislative Decree 81/08 and subsequent amendments), exposure to specific biomechanical risks significantly increases the incidence of musculoskeletal disorders during pregnancy. Workers employed in sectors such as healthcare (nurses, healthcare assistants), large-scale retail (cashiers, sales assistants), manufacturing, and cleaning services are particularly vulnerable.

INAIL highlights how prolonged standing, manual handling of loads (even light but repetitive), incongruous postures, and whole-body vibrations are aggravating factors for biomechanical overload of the spine and pelvis. Company risk assessment must mandatorily take into account the physiological changes of the pregnant woman, providing for the adaptation of the workstation, frequent breaks, and, where necessary, a change of duties to prevent the exacerbation of sacroiliac and lumbar pain.

Symptomatology and Differential Diagnosis

The clinical picture typically presents with a dull, deep, or stabbing pain localized in the region of the sacral dimples (often described by patients as corresponding to the “dimples of Venus”). The pain can be unilateral or bilateral and tends to radiate towards the gluteal region, the posterior aspect of the thigh, and sometimes towards the pubic symphysis or groin. Unlike true radiculopathies, pain of sacroiliac origin rarely extends below the knee and is not accompanied by neurological deficits (alterations in sensation, strength deficits, or altered deep tendon reflexes).

Activities that exacerbate the symptomatology are those that require asymmetrical load transfer on the pelvis. These include:

• Walking long distances or climbing stairs.
• Maintaining prolonged standing.
• Transitioning from sitting to standing.
• Turning in bed (trunk rotation with fixed pelvis).
• Bearing weight on one leg (e.g., while dressing).

Differential diagnosis is a critical step that must be performed by qualified healthcare personnel. It is imperative to distinguish this condition from lumbosciatica (compression of lumbar nerve roots, often due to a herniated disc), pubic symphysis dysfunction (which presents predominantly anterior pain), and obstetric, renal, or rheumatological conditions. For this reason, the importance of always consulting your doctor or physical therapist before undertaking any therapeutic path is reiterated.

Clinical Assessment of sacroiliac pain in pregnancy

The clinical assessment of sacroiliac pain in pregnancy requires specific expertise. Since the use of diagnostic imaging investigations employing ionizing radiation (such as X-rays or CT scans) is strictly contraindicated during gestation to protect fetal health, diagnosis relies almost exclusively on accurate anamnesis and physical objective examination.

The healthcare professional (doctor or physical therapist) will use a battery of clinical tests validated in the literature. The cluster of pain provocation tests described by Laslett (Laslett et al., 2005) represents the clinical gold standard for identifying sacroiliac dysfunctions. However, during pregnancy, some of these tests must be adapted or avoided due to abdominal bulk and the inability to assume a prone position in the second and third trimesters.

The most frequently used and safe clinical tests include:

• Distraction Test (Gapping Test): With the patient supine, the examiner applies cross-pressure on the anterior superior iliac spines (ASIS), pushing them outwards, thereby tensioning the anterior sacroiliac ligaments.
• Compression Test (Approximation Test): With the patient in a side-lying position, downward pressure is applied to the iliac crest, compressing the sacroiliac articular surfaces.
• Thigh Thrust: With the patient supine, the hip is flexed to 90 degrees, and the examiner applies an axial force along the femur, inducing a shear force on the sacroiliac joint.
• Active Straight Leg Raise (ASLR): Developed by Mens et al. (2001), this test assesses load transfer capacity. The supine patient is asked to actively lift a straight leg approximately 20 cm. If the movement elicits pain or is impossible, the examiner applies manual compression to the pelvis (simulating a pelvic belt). If compression facilitates lifting and reduces pain, the test indicates a “force closure” deficit and a favorable prognosis for the use of pelvic orthoses and motor stabilization.

Physiotherapy Treatment and Conservative Management

The management of the clinical picture must be strictly conservative, personalized, and progressive. The primary goal of physiotherapy treatment is not the complete resolution of ligamentous laxity (which is physiological and hormonally induced), but rather pain modulation, restoration of correct lumbopelvic biomechanics, and improvement of dynamic stability through the optimization of “force closure”.

Manual Therapy

Manual therapy, performed exclusively by a specialized physical therapist, proves extremely useful for alleviating painful symptoms. The techniques employed must be gentle, non-invasive, and respectful of the pregnant woman’s physiology. High-velocity, low-amplitude (HVLA – thrust) vertebral manipulations at the lumbopelvic level are absolutely contraindicated due to ligamentous hyperlaxity. Instead, the following are preferred:

• Low-intensity joint mobilizations: Grade I and II techniques (according to Maitland) to modulate pain through neurophysiological mechanisms (gate control theory) without stressing the ligaments.
• Soft tissue treatment: Therapeutic massage, myofascial release, and trigger point inhibition techniques directed at overloaded musculature, particularly the piriformis muscle, quadratus lumborum, glutes, and thoracolumbar fascia.
• Muscle Energy Techniques (MET): Used to gently correct any positional asymmetries of the pelvis by utilizing the patient’s active isometric muscle contractions.

Use of Orthoses: The Pelvic Belt

In cases where the ASLR test is positive and a marked stability deficit is evident, the use of a pelvic (or sacroiliac) belt represents a highly effective therapeutic aid. The belt, correctly positioned below the anterior superior iliac spines and above the greater trochanter of the femur, provides external mechanical compression that temporarily compensates for the lack of “form closure”. This support reduces shear forces during walking and weight-bearing activities, offering immediate relief. It is essential that the indication, choice of model, and instructions on usage time be provided by your doctor or physical therapist, to avoid improper use that could lead to muscle deconditioning.

Recommended Therapeutic Exercises

Therapeutic exercise represents the central pillar of medium- and long-term rehabilitation. The program must focus on the specific recruitment of deep stabilizing musculature (core stability) and strengthening of the gluteal muscles, avoiding exercises that increase intra-abdominal pressure or cause asymmetrical shear forces on the pelvis. Below are some types of exercises frequently integrated into rehabilitation protocols, whose execution must always be supervised and approved by the referring healthcare professional.

1. Activation of the Transversus Abdominis and Pelvic Floor

The transversus abdominis muscle acts as a natural corset, stabilizing the sacroiliac joints and the lumbar spine. Simultaneous activation of the pelvic floor enhances its stabilizing effect.

• Position: Quadruped (on all fours), with hands under shoulders and knees under hips. The spine should be in a neutral position.
• Execution: Inhale deeply, relaxing the abdomen. During exhalation, gently draw the navel towards the spine (as if pulling the belly away from the floor) and simultaneously contract the pelvic floor muscles (as if holding back urine).
• Parameters: Hold the contraction for 5-8 seconds while continuing to breathe normally. Repeat 10 times.

2. Gluteus Maximus Strengthening (Modified Glute Bridge)

The gluteus maximus is a key muscle for “force closure” of the sacroiliac joint, thanks to its insertions on the thoracolumbar fascia and the sacrotuberous ligament.

• Position: Supine, with knees bent and feet flat on the floor, hip-width apart. (Note: if the supine position causes dizziness or discomfort due to inferior vena cava compression in the third trimester, this exercise should be avoided or performed with the torso elevated on pillows).
• Execution: Contract the glutes and slowly lift the pelvis off the floor until a straight line is formed between the knees, pelvis, and shoulders. Avoid excessively arching the lower back.
• Parameters: Hold the position for 3-5 seconds, lower slowly. Perform 3 sets of 10 repetitions.

3. Gluteus Medius Strengthening (Clam Shell)

The gluteus medius is fundamental for lateral pelvic stability during ambulation.

• Position: Side-lying, with knees bent at approximately 45 degrees and feet together. A pillow can be placed under the abdomen for support.
• Execution: Keeping the heels in contact and the pelvis stable (avoiding rolling backward), lift the top knee towards the ceiling, opening the legs like a clam shell.
• Parameters: Slow and controlled movement. 3 sets of 12 repetitions per side.

Prevention and Daily Ergonomics

Pain management inevitably involves postural education and modification of daily living activities (ADLs). Adopting correct ergonomic strategies minimizes repeated microtraumas and reduces the load on the pelvic joints.

Postural Hygiene and Daily Movements

• Night rest: It is recommended to sleep in a side-lying position (preferably on the left side to promote venous return), placing a thick pillow between the knees and ankles. This precaution keeps the hips in neutral alignment, preventing internal rotation and adduction of the femur which would tension the sacroiliac ligaments.
• Positional changes: To get out of bed, it is essential to use the “log roll” technique. From a supine position, bend the knees, roll onto one side keeping shoulders and pelvis aligned, let the legs swing off the bed, and push up with the arms. This avoids torsional forces on the pelvis.
• Walking and stairs: Avoid excessively long strides. When climbing stairs, proceed slowly, placing the foot on the step first and then extending the hip, avoiding “pulling oneself up” with the back. If the pain is severe, tackle stairs one step at a time, bringing both feet onto the same step before proceeding to the next.
• Dressing: Avoid bearing weight on one leg. Put on pants, socks, and shoes while seated.
• Lifting weights: Minimize lifting loads. If unavoidable, bend the knees while keeping the back straight and hold the load as close to the body as possible, preemptively activating the core musculature.

Postpartum Considerations

Although in most cases the symptoms tend to regress spontaneously in the weeks or months following childbirth, thanks to the restoration of normal hormonal levels and the reduction of mechanical load, a percentage of women (approximately 7-10%) continue to experience chronic pain. The postpartum period presents new biomechanical challenges, such as repeated lifting of the newborn, breastfeeding in prolonged postures, and carrying strollers and car seats.

It is essential not to neglect persistent postpartum pain. A physiotherapy rehabilitation program aimed at recovering rectus abdominis diastasis (if present), pelvic floor re-education, and global restoration of lumbopelvic strength and stability is strongly indicated. Even at this stage, consulting your doctor or physical therapist is the first step to ensure optimal recovery and prevent

Sources and Scientific References

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