Postpartum low back pain and sacroiliac joint dislocation

The most common complications of pregnancy are back pain and urinary incontinence, both of which are closely related to changes in the pelvis. The incidence of back pain after childbirth is 50-70% [1]. The main symptom is lumbar pain. The location of the back pain is often on the inside or outside of the affected limb, making walking difficult and coughing painful. In traditional Chinese medicine, this is called "arthralgia", which refers to pain, soreness, numbness, and heaviness in the limbs, waist, knees, and joints during the postpartum period. Arthralgia is a disease caused by wind, cold, and dampness invading the bones and muscles, blocking the meridians and causing pain. Because women's qi and blood are severely damaged after childbirth, their defense against external pathogens are insufficient, and they are more susceptible to external pathogens and are more susceptible to this disease. [2] After most women give birth, their back pain will gradually ease as their hormone levels return to normal. If the pain persists, they should seek medical attention immediately.

Why does lower back pain occur after childbirth?

Many studies have shown that the sacroiliac joint is the source of low back and leg pain in women after childbirth. [3,4] The sacroiliac joint is the base of the spine and the hub connecting the upper and lower limbs. It is the joint that transmits gravity. When the sacroiliac joint is dislocated, the tension of the surrounding ligaments and muscles will increase, the stress on the joint will increase, and cause pain. [5,6]

Why is sacroiliac joint dislocation more likely to occur after childbirth?

① Changes in the body's force line, ② Weakness of the core muscles, ③ Ligament relaxation.

① Changes in the body's force line (spinal biomechanics and morphology) are important factors. In the second trimester, the abdomen increases due to the enlarged uterus and fetal weight (the weight increases by about 30%), and the body's center of gravity moves forward. In order to compensate for this change in center of gravity, the curvature of the waist, chest, and cervical spine increases, the pelvis tilts forward, the knee joints hyperextend, and the static stability of the spine decreases. [7] During this process, the sacroiliac joint, as an unstable part of the pelvis, is very easy to dislocate. [8]

②The transverse abdominal muscles and pelvic floor muscles are equally important for female lumbar-pelvic stability. After pregnancy, the abdominal muscles and pelvic floor muscles will weaken or even be damaged, resulting in insufficient core muscle strength, reduced control of normal movement patterns, increased load between joints during exercise, and easy to cause muscle strain pain. [9,10] ③Under normal circumstances, the gravity transmitted from the upper limbs is borne by the bones and ligaments at the sacroiliac joint and transmitted to the lower limbs. However, after childbirth, due to hormone secretion*, the ligaments relax, the force that the sacroiliac joint needs to bear increases, and the stability of the sacroiliac joint decreases. If coupled with improper postpartum rest (standing or sitting too long) and various injuries to the mother's pelvis during childbirth, the relaxed sacroiliac ligaments can be damaged and cannot recover their elasticity in time. [11]

* Before a woman gives birth, her ovaries secrete relaxin, which relaxes the ligaments and soft tissues around the pelvis, widens the pelvis, and separates the pubic symphysis to open the pelvic cavity and facilitate childbirth. [12]

Relaxin: It can relax the pelvic ligaments, loosen the pubic symphysis, and dilate the cervix and vagina

Other complications of sacroiliac joint dislocation

Urinary incontinence; pubic pain; widening of the hips; constipation; scoliosis; chest tightness and shortness of breath*, etc.

*This chest tightness and shortness of breath is caused by thoracic facet joint disorder[13], which can be caused by changes in pelvic position.

References

[1]Bastiaanssen JM, de Bie RA, Bastiaenen CHG, et al. A historical perspective on pregnancy-related low back and/or pelvic girdle pain[J]. European Journal of Obstetrics & Gynecology and Reproductive Biology, 2005, 120(1): 3–14.

[2] Chen Quanhan, Ma Zhijie, Wu Xiaopeng. Research progress on the treatment of postpartum low back pain with traditional Chinese medicine [J]. Chinese Journal of Traditional Chinese Medicine Traumatology, 2014, 22(10): 73–74.

[3]Stuge B. Evidence of stabilizing exercises for low back- and pelvic girdle pain – a critical review[J]. Brazilian Journal of Physical Therapy, 2019, 23(2): 181–186.

[4]O'Sullivan PB, Beales D J. Diagnosis and classification of pelvic girdle pain disorders—Part 1: A mechanism based approach within a biopsychosocial framework[J]. Manual Therapy, 2007, 12(2): 86–97.

[5]Bussey MD, Milosavljevic S. Asymmetric pelvic bracing and altered kinematics in patients with posterior pelvic pain who present with postural muscle delay[J]. Clinical Biomechanics, 2015, 30(1): 71–77.

[6]Vleeming A, Schuenke MD, Masi AT, et al. The sacroiliac joint: an overview of its anatomy, function and potential clinical implications[J]. Journal of Anatomy, 2012, 221(6): 537–567.

[7]Biviá-Roig G, Lisón JF, Sánchez-Zuriaga D. Changes in trunk posture and muscle responses in standing during pregnancy and postpartum[J]. JL McCrory. PLOS ONE, 2018, 13(3): e0194853.

[8]Aldabe D, Milosavljevic S, Bussey M D. Is pregnancy related pelvic girdle pain associated with altered kinematic, kinetic and motor control of the pelvis? A systematic review[J]. European Spine Journal, 2012, 21(9): 1777–1787.

[9]Sakamoto A, Gamada K. Altered musculoskeletal mechanics as risk factors for postpartum pelvic girdle pain: a literature review[J]. Journal of Physical Therapy Science, 2019, 31(10): 831–838.

[10] Li Zhen, Zhang Xilin. Research progress on postpartum lumbar-pelvic complex pain syndrome[J]. International Journal of Obstetrics and Gynecology, 2020, 47(05): 579–583.

[11] Tang Jianhua, Chen Jianfeng, Tian Xiaowu. Observation on the efficacy of manipulation in treating sacroiliac joint-induced low back pain after lumbar spine surgery[J]. Modern Journal of Integrated Traditional Chinese and Western Medicine, 2011, 20(13): 1577-1578+1686.

[12]Xu Zilian, Wang Deqiang. Analysis of diagnosis and treatment of postpartum low back and leg pain[J]. Journal of Binzhou Medical College, 2004(04): 310.

[13] Zhou Xuelong. A review of the related diseases of thoracic facet joint disorder[J]. Guangxi Journal of Traditional Chinese Medicine, 2006(05): 4–6.