Research Review By Dr. Ceara Higgins©


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Date Posted:

May 2013

Study Title:

Is pregnancy related pelvic girdle pain associated with altered kinematic, kinetic and motor control of the pelvis? A systematic review


Aldabe D, Milosavljevic S, Bussey MD

Author's Affiliations:

School of Physical Education, School of Physiotherapy, and Centre for Physiotherapy Research, University of Otago, New Zealand

Publication Information:

European Spine Journal 2012; 21: 1777-1787.

Background Information:

Research has shown that approximately 20% of all pregnant women will experience pelvic girdle pain during their pregnancy and have continuing symptoms into the postpartum period. It is commonly accepted that this is a result of hormonal changes and mechanical changes associated with pregnancy. High levels of relaxin have long been suggested to have an impact on pregnancy related pelvic girdle pain (PPGP). However, a recent systematic review investigated the relationship between pregnancy related PPGP and relaxin levels, finding a low level of evidence to support such a relationship, with the highest quality studies all showing no association between relaxin levels and PPGP (1). This leaves the possibility of a connection between PPGP and mechanical changes during pregnancy. The purpose of this review was to review the existing literature on this connection.

Pertinent Results:

Mechanics of the Pelvis:

One of the first studies on this topic was performed by Abramson et al. in 1934 (2)! In that study, they compared the symphysis pubis width of 25 PPGP patients, as measured by radiograph, to a control group of 136 primipara and multipara women without PPGP and showed a 15% greater width in the symphysis pubis of those with PPGP. However, it should be noted that no statistical analysis was performed.

In a similar study published in 1968 by Gwozdz and Oko (3), the control group and women with PPGP showed similar symphysis pubis widths. The authors suggested that the shape of the symphysis may play a more significant role, as the majority of the individuals studied with severe cases of PPGP were identified as having sysmphysis type 4 or 5 (those having edges or pubic bones that diverge downward or upward).

Bjorklund et al. conducted two studies (4, 5) using ultrasonography to assess the width of the symphysis pubis. In their first study, four groups in the 12th and 35th weeks of pregnancy were assessed. Those with severe pain and no postpartum symptoms showed a greater symphyseal width than those with no or mild pain and no postpartum pain, or those with severe pain during pregnancy and pain postpartum. In the second study, a group of women with PPGP at 35 weeks were compared with a group of women with no pain at 35 weeks of pregnancy. Those with pain were found to have greater symphyseal widths than those with no pain.

Damen et al. conducted two studies (6, 7) on PPGP and asymmetric SI joint laxity. In the first study, 37% of women with PPGP showed asymmetric SI joint laxity while only 4.4% of those with no pain demonstrated laxity. In the second study, more SI joint laxity was found in women with moderate to severe PPGP during pregnancy and postpartum.

Motor Control:

Sihvonen et al. (8) performed a cohort study on the flexion relaxation phenomena in the paraspinal muscles (FLR) during the 20th week of pregnancy and its correlation to PPGP in the 30th week of pregnancy. Patients with activation of the paraspinal muscles during flexion during the second trimester were much more likely to show pain during the last trimester in this study.

de Groot et al. (9) also studied muscle activity and PPGP. They looked at activity of the rectus femoris, external oblique, psoas, and adductor longus bilaterally and their force production during the active SLR test. Individuals with PPGP showed higher levels of muscle activation during the ASLR.

Dumas et al. (10) looked at muscle fatigability and whether this variable could be used to predict low back pain. Measurements were taken at 14, 24, and 34 weeks with regard to muscle fatigability. The occurrence and severity of low back pain was also assessed at these time points as well as weeks 19 and 29. There seemed to be no connection between increased fatigability and predicting LBP during pregnancy, although it was noted that the study involved a very small sample size.

Finally, Wu et al. (11) compared mobility of the pelvis, lumbar and thoracic regions during gait in pregnant women with no pain and those with PPGP using a 3D kinematic analysis. Subjects with PPGP showed increased mobility of the pelvis, lumbar and thoracic regions.

Clinical Application & Conclusions:

With consideration to the quality of the included studies, this review found only a moderate level of evidence for a relationship between PPGP and altered pelvic mechanics and/or motor control. As a result, clinicians would be well served to consider and investigate for changes in their pregnant patients’ pelvic mechanics and motor control as possible causes of their pelvic pain. For the moment, the level of evidence cannot provide us with general recommendations, requiring that each patient be approached on an individual basis, carefully considering their history of pain and injury, biomechanics, activity level, and so on.

Study Methods:

The authors searched for cohort, cross-sectional, or case controlled observational studies in Medline, Amed, EMBASE, Proquest, Web of Science, and Scopus (1966 to 2011). To be included, studies had to investigate the association between PPGP and mechanical factors, and motor control of the pelvis. Studies were included in the review regardless of the age of the participants and stage of the pregnancy. This review included studies written in English, Spanish, French, and Portuguese. Any studies found that were related to literature or systematic reviews, were theses or dissertations, or did not consider PPGP as a musculoskeletal disorder were excluded from the review. Once the initial search was performed one author scanned the reference lists for additional articles. Then one reviewer screened articles based on the inclusion and exclusion criteria, followed by a second review by two of the authors. Selected studies were analyzed with the Newcastle-Ottawa scale by two of the authors to determine the risk of bias in each study and determine study quality. Studies scoring five or more points out of a maximum of nine points were considered high quality.

Study Strengths / Weaknesses:

Strengths: The study was performed by a number of authors who independently assessed the included studies, which helps avoid researcher bias. Moreover, the authors searched a variety of databases in order to maximize their returned results and avoid search limitation.

Weaknesses: Two of the higher quality studies had a high risk of bias related to the selection of participants, lack of clear definition of the assessment for PPGP, appropriate control of the non-pain groups, or control for known risk factors for low back pain, such as history of LBP or PPGP, BMI, parity, smoking, or stress levels.

Additional References:

  1. Aldabe D et al. Pregnancy-related pelvic girdle pain and its relationship with relaxin levels during pregnancy: a systematic review. Eur Spine J 2012; 21: 1769-1776.
  2. Abramson D, Roberts S, Wilson PD. Relaxation of the pelvic joints in pregnancy. Surg Gynecol Obstet 1934; 58: 595–613.
  3. Gwozdz A, Oko S. Radiological evaluation of the changes of pubic symphysis during pregnancy and puerperium. Gynaecologia 1968; 165(1):31–37
  4. Bjorklund K, Nordstrom ML, Bergstrom S. Sonographic assessment of symphyseal joint distention during pregnancy and post partum with special reference to pelvic pain. Acta Obstet Gynecol Scand 1999; 78(2): 125–130.
  5. Bjorklund K et al. Symphyseal distention in relation to serum relaxin levels and pelvic pain in pregnancy. Acta Obstet Gynecol Scand 2000; 79(4): 269–275.
  6. Damen L et al. Pelvic pain during pregnancy is associated with asymmetric laxity of the sacroiliac joints. Acta Obstet Gynecol Scand 2001; 80(11):1019–1024.
  7. Damen L et al. The prognostic value of asymmetric laxity of the sacroiliac joints in pregnancy-related pelvic pain. Spine 2002; 27(24): 2820–2824.
  8. Sihvonen T et al. Functional changes in back muscle activity correlate with pain intensity and prediction of low back pain during pregnancy. Arch Phys Med Rehabil 1998; 79(10): 1210– 1212.
  9. de Groot M et al. The active straight leg raising test (ASLR) in pregnant women: differences in muscle activity and force between patients and healthy subjects. Man Ther 2008; 13(1): 68–74.
  10. Dumas GA et al. Fatigability of back extensor muscles and low back pain during pregnancy. Clin Biomech 2010; 25(1): 1–5.
  11. Wu WH et al. Gait in pregnancy-related pelvic girdle pain: amplitudes, timing, and coordination of horizontal trunk rotations. Eur Spine J 2008; 17(9):1160–1169.