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Research Review By Dr. Ceara Higgins©


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Date Posted:

January 2013

Study Title:

Adverse events from spinal manipulation in the pregnant and postpartum periods: A critical review of the literature


Stuber KJ, Wynd S & Weis CA

Author's Affiliations:

Division of Graduate Education and Research, Canadian Memorial Chiropractic College, Toronto, ON; Texas Chiropractic College, Pasadena, TX

Publication Information:

Chiropractic & Manual Therapies 2012; 20: 8.

Background Information:

Musculoskeletal pain during pregnancy is common, with low back pain reported in 50-85% of women. Of these women, 8-20% report persistent symptoms two to three years postpartum – it can become a lasting problem! During pregnancy, LBP could be the result of increased stress on the sacroiliac joints, intervertebral discs, and facet joints due to increased anterior weight carriage and the resultant increase in lumbar lordosis (1). In addition, the potential consequences of pregnancy of soft tissues should also be considered as possible mechanisms of pain generation.

Previous studies of chiropractic care during pregnancy have shown positive outcomes for patients. In a 2009 study by Murphy, Hurwitz, and McGovern, 51% of patients with pregnancy related lumbopelvic pain treated by a health team including chiropractors, physicians, and physical therapists showed clinically significant improvements in disability, while 67% showed clinically significant improvements in pain (2). However, like most studies involving pregnant patients, a small sample size limited the amount of data obtained, making it less likely that adverse events or complications would be observed.

When surveyed, chiropractors report frequently consulting pregnant patients as well as believing spinal manipulative therapy (SMT) to be a safe treatment for musculoskeletal pain during pregnancy. Therefore, the authors of this review attempted to study the potential risks of SMT in this specific subset of patients, so evidence-informed clinicians can offer a balanced perspective when discussing treatment options.

Literature Synthesis:

Observational Cohort Study:

The one observational cohort study included 78 subjects suffering from pregnancy-related lumbopelvic pain. The study reported 3 adverse events, all in the form of increased pain following treatment. In 2 of these cases, the pain was reported to resolve in less than 48 hours, while in the third case the pain was reported to resolve one week after treatment.

Case Studies:

Four cases were identified via the literature search. Two cases reported adverse events during pregnancy, while the other two dealt with post-partum issues. The first case featured a woman who was 15 weeks pregnant, who presented to a general medical practitioner. She received a single cervical manipulation and a paravertebral injection. Five days later, she reported swelling and neck pain, and was found on MRI to have a pathological type II fracture of the odontoid with ventral displacement, spinal cord compression, and paravertebral displacement secondary to a C2 vertebral body tumor.

In the second case, a woman presented to a chiropractor at 29 weeks of pregnancy with a complaint of low back pain. She received a cervical manipulation and reported having numbness and pain in the neck and arms during treatment. She then felt several seconds of transient paralysis in the upper extremities and numbness in the lower extremities. A subsequent MRI showed an epidural hematoma on the right side creating a mass effect on the spinal cord. After 2 weeks she was discharged from hospital with minimal residual parestheias affecting the posterior neck.

The third case study reported on a woman who presented to a chiropractor 5 weeks post-partum with a complaint of right-sided neck pain. Thirty minutes after receiving a cervical manipulation, she reported memory loss - which later resolved. One day subsequent to the manipulation, she patient reported poor coordination in her right hand, difficulty articulating, and an unsteady gait. An MRI showed a right-sided cerebellar infarct and a wedge shaped area of increased T2 signal intensity in the right antero-superior cerebellar cortex. The patient recovered fully within one month.

The final case study reported on a patient who presented to a physiotherapist 2 weeks post-partum with a complaint of head and neck pain. The physiotherapist performed a non-described provocative test and vertical traction coupled with lateral head rotation. This resulted in vertigo within seconds. After immediate discontinuation of the procedure the patient stood and experienced ataxia, dysarthria, and right-sided numbness affecting the entire body. A cerebral angiography showed total occlusion of the left vertebral artery and a large thrombus in the basilar artery. The patient was discharged after 2 months in hospital. However, she had persistent issues with coordination, sensation, ataxia, and left-sided paralysis affecting the palate and tongue.

Systematic Reviews:

No adverse effects were noted in either of the systematic reviews.

Clinical Application & Conclusions:

The low number of reported adverse effects following spinal manipulation in both pregnant and post-partum patients indicates that SMT could be considered to be a safe method of treatment for musculoskeletal pain. However, due to the seriousness of the reported adverse effects following cervical manipulation, it is important to fully assess pregnant and post-partum patients for possible risk factors to cervical manipulation and consider the possibility that this treatment may be contraindicated in this patient group – more specific research is required on this topic. (EDITOR’S NOTE: it was interesting that all of the case reports included here discussed adverse events after cervical manipulation/procedures. In one case where this occurred, the initial complaint was low back pain, which begs the question of why the neck was manipulated! In any event, perhaps adverse reactions relating to neck manipulation are more likely to be written and/or published, or there may be more to this issue. It is also important to remember that in one of these cases, the practitioner was a medical doctor, not a chiropractor or physiotherapist.)

Improved reporting of adverse events in pregnant and post-partum patients is needed and further research on this topic is essential to determine the safety of SMT for pregnant patients.

It is important to keep in mind that certain contraindications to manual therapy in pregnancy have been noted and should be accounted for before beginning a treatment plan. These include vaginal bleeding, rupture of the amniotic membranes, cramping, pelvic pain of sudden onset, premature labour, ectopic pregnancy, placenta previa or abruption, and moderate-to-severe toxemia. As well, the use of electrical modalities such as stimulation and ultrasound and any forms of radiodiagnostic imaging are all contraindicated during pregnancy (1).

Study Methods:

The authors searched PubMed (including MEDLINE), CINAHL, and the Index to Chiropractic Literature (ICL) from the earliest date included in the database through October of 2011. Clinical studies published in peer-reviewed journals that studied female patients during pregnancy or up to six weeks postpartum who received treatment for musculoskeletal pain that included SMT were included in the study. Four case reports, 1 prospective observational cohort study, and 2 systematic reviews were included in the critical review. Each study included was rated using the Scottish Intercollegiate Guidelines Network (SIGN).

Study Strengths / Weaknesses:

The authors included the major medical literature databases in their literature search and presented a balanced summary of the existing research on this topic.

The authors found very few studies to include in their analysis, and those that were discovered included case studies and a prospective cohort study, both of which represent lower levels of evidence. The study was also potentially limited by the exclusion of articles in any languages other than English and French. Finally, the study was limited by the variability of practitioners reporting adverse effects. Since the studies reviewed included manual therapies performed by chiropractors, physiotherapists, and medical doctors, it is hard to determine the safety of SMT in pregnancy and post-partum patients specifically treated by chiropractors or physiotherapists.

Additional References:

  1. Borggren, CL. Pregnancy and chiropractic: a narrative review of the literature. Journal of Chiropractic Medicine. 2007; 6: 70-74.
  2. Murphy, DR, Hurwitz, EL, & McGovern EE. Outcome of pregnancy-related lumbopelvic pain treated according to a diagnosis-based decision rule: a prospective observational cohort study. Journal of Manipulative Physiological Therapy. 2009; 32(8): 616-624.

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