Pregnancy-related low back pain (with and without pelvic girdle pain)
Low back pain in pregnancy is defined as pain in the lower back, located above the lumbosacral junction, with or without radiation in the legs,1 although this is a narrower definition than that used in the general population,2 in which low back pain is usually defined as pain and discomfort localised below the costal margin and above the inferior gluteal folds, with or without leg pain. Pelvic girdle pain (PGP) is musculoskeletal pain located within the pelvic area between the posterior iliac crest and the gluteal folds, particularly in the vicinity of the sacroiliac joints, that develops in relation to pregnancy.3,4 The pain may radiate in the posterior thigh and can also occur in conjunction with or separately from pain in the pubic symphysis.
Low back pain and PGP during pregnancy are common and, although they can occur separately, many women experience both. Although prevalence estimates vary between studies owing to different definitions and diagnostic criteria, low back pain is reported to affect between 45% and 75% of women at some stage during their pregnancy,5,6 with a point prevalence of approximately 34%.6 Prevalence estimates for PGP range widely and include 20% overall,3 35% to 50% in early pregnancy and 60% to 70% in late pregnancy.3,7,8 The pain increases with advancing pregnancy, is usually worse at night and interferes with sleep, daily activities and work.7 It is a common reason for sick leave, with reports suggesting that 20–23% of women take sick leave because of their pain.6,9 Studies have shown that pregnant women with back pain have lower quality of life than pregnant women without back pain.10 Hence, low back pain and PGP in pregnancy negatively affect activities of daily life and quality of life during pregnancy and are an important health problem. Some have reported an increasing number of affected women requesting induction of labour or elective caesarean section before the recommended 39th week of gestation in order to achieve symptomatic relief.11 Although longitudinal data are limited, it has been estimated that in 1 in 10 women the pain becomes long-lasting and disability persists after childbirth.12,13 Pregnancy-related low back pain has been found to reduce soon after delivery but it improves in few women later than 6 months post partum.14 By 2 years after giving birth, the prevalence of back pain has been reported to fall to the same level found pre pregnancy (18%).
A range of biomedical, psychological and social factors may be important predictors of non-recovery from low back pain in pregnancy, but in general these have not been well studied. Cohort studies15,16 suggest that predictors of poor recovery from symptoms post partum include older age, work dissatisfaction and the presence of combined low back pain and PGP in comparison with pain in either location alone. There is some evidence that women with combined pubic symphysis pain and bilateral posterior PGP in pregnancy have a slower recovery than those women with fewer pain locations12,16 and that women with a high number of other bodily pain sites are more likely to have high pain intensity scores and postpartum non-recovery.17 Guidelines3 suggest risk factors for PGP include a previous history of low back pain and previous trauma to the pelvis. Studies of low back pain in general have shown the important role of psychosocial obstacles to recovery18,19 and there is some evidence that psychological factors such as a lack of belief in improvement,20 exaggerated negative thoughts or catastrophising about the pain, fear avoidance beliefs21 and distress (anxiety and depression) are also important predictors of poor outcome in women with pregnancy-related back pain.8
Current clinical management
Women experiencing these problems most often report them to their midwives; for example, in an Australian study 71% reported their pain to their maternity carer,6 but it appears that few receive much in the way of treatment. Pierce et al.6 found that only 25% of women received any treatment. There are no high-quality UK data that describe current treatment for pregnancy-related low back pain or PGP. It is most often accepted as a ‘normal’ discomfort of pregnancy6,11 with some suggesting this may be related to health professionals’ lack of knowledge about available treatments and fear of possible harmful effects of treatment on the developing fetus.11 Women are encouraged to believe that their pain is temporary and self-limiting (which may not always be the case), a part of the normal aches and pains of pregnancy,11 and those involved in their care tend to give women information on how to self-manage7 through postural changes, adaptations in lifting techniques, simple exercises to try at home, rest, heat and cold therapy, supportive belts and pillows, massage and relaxation. Some women, however, do proceed to use a range of treatments, such as physiotherapy-led exercise, manual therapy, acupuncture, massage, transcutaneous electrical nerve stimulation (TENS) and mobility aids as well as safe pharmacological options (mostly paracetamol) and, much less commonly, epidural injections.6,7,11 None of these treatment options has been well researched in women with pregnancy-related back pain.
Current NHS practice varies across services and geographical regions. Most women are not referred from their midwives or general practitioners (GPs) to other health professionals for treatment, but are advised to self-manage. The self-management advice tends to follow the guidance from national associations such as the National Childbirth Trust (www.nct.org.uk) or the Association of Chartered Physiotherapists in Women’s Health (ACPWH; http://pogp.csp.org.uk/) and only the most severely affected women are referred to physiotherapists and receive individual assessment, advice or treatment. We estimate that approximately 10–20% of women are likely to be referred to see a NHS physiotherapist for help with severe back pain and/or PGP. In North Staffordshire, for example, 10% of women with back pain in pregnancy are referred by their midwife (and some cases by their GP), to women’s health physiotherapists, who invite them to a group advice and education session, and are offered individual care following the group session only if needed. The referral is left open for the duration of the pregnancy so that the woman can access further physiotherapy support if needed. In other services, physiotherapists offer individual assessment and individualised advice and treatment.
Acupuncture
Acupuncture is based on needle stimulation of points on the surface of the body (acupuncture points) and originates from traditional Chinese medicine (TCM). It encompasses a variety of different procedures and techniques but most often is based on penetrating the skin at anatomical points on the body with thin, solid, metallic needles that are manipulated manually or by electrical stimulation. Since its introduction to the West several hundred years ago, many different styles of acupuncture have developed, including Japanese meridian therapy, French energetic acupuncture, Korean constitutional acupuncture and Lemington five-element acupuncture.22 Although similar to traditional acupuncture, these various styles have their own distinct characteristics. In the past several decades, new forms and styles of acupuncture have evolved, including ear (auricular), hand, foot and scalp acupuncture. As a result of advances in the understanding of the neurophysiology of pain and acupuncture, the boundary between acupuncture and conventional medicine is changing. For example, a simplified and more empirical Western approach to acupuncture of local dry needling at the site of pain or at points in the vicinity of pain, called trigger points, is popular among conventional health professionals (medical doctors and physiotherapists). Modern acupuncturists typically use a combination of both TCM meridian acupuncture points and non-meridial (or extrameridial) points. Once appropriate points are selected, the therapist inserts a needle into each point by gently tapping it into place and rotating it until the patient experiences a needle sensation or de-qi, usually described as a tingling, numbness or dull ache sensation. A typical session with acupuncture includes treatment with a varying number of needles (1–30) inserted and kept in place for 20–30 minutes, during which period the therapist may stimulate the needles by rotating or tapping them. Some therapists may also use electrical stimulation (in which an electrical stimulator is connected to the acupuncture needles), injection acupuncture (herbal extracts are injected into acupuncture points), heat lamps or moxibustion. Although the neurophysiological mechanisms of acupuncture are well established in research for experimental pain, the exact mechanisms underlying the action of acupuncture in clinical practice are still unclear.23 In terms of Western scientific principles, it is uncertain how acupuncture may help musculoskeletal pain such as back pain in pregnancy. Current theories suggest that acupuncture may produce its effects through the nervous system by stimulating the production of biochemicals such as endorphins and other neurotransmitters that influence pain sensation; that acupuncture works through the gate control theory of pain, in which the sensory input is inhibited in the central nervous system by another type of input (the needle); or that the presence of a foreign substance (the needle) within the tissue of the body stimulates vascular and immunomodulatory factors such as mediators of inflammation.22
The use of acupuncture for musculoskeletal problems appears to be increasing and acupuncture has been recommended within recent UK national guidelines for the management of persistent non-specific low back pain.24 One of the few randomised trials conducted within the UK25 concluded that there was weak evidence of an effect of a short course of acupuncture on persistent non-specific low back pain (rather than back pain in pregnancy) at 12 months, but that at 24 months there was stronger evidence of a small benefit compared with usual GP care. The health economic analysis conducted alongside that trial26 concluded that acupuncture confers a modest health benefit for minor extra cost to the NHS. The most recent Cochrane Review of acupuncture for low back pain27 included 35 trials, but only three of these were of acute low back pain. Overall, no firm conclusions could be drawn but there was some evidence of short-term pain relief and functional improvement from acupuncture compared with no treatment or sham treatment. There was also some evidence that acupuncture, added to other conventional therapies, relieves pain and improves function better than conventional therapies alone.
A small number of trials have evaluated acupuncture for low back pain and PGP during pregnancy.28–33 To date, two rigorously conducted systematic reviews have been published.7,34 The first of these was a Cochrane Review of eight studies (1305 participants) testing the effects of adding various pregnancy-specific exercises, physiotherapy, acupuncture and pillows to standard pre-natal care.7 That review found positive results for the additional benefit of strengthening exercises, pelvic tilt exercises and exercise in water for women with low back pain. Both acupuncture and stabilising exercises relieved PGP more than usual pre-natal care, and acupuncture provided more relief from evening pain than exercise. One study found that acupuncture was more effective than physiotherapy for pain reduction,28 although it was unclear if this was a result of the type of treatment delivery (acupuncture was individually delivered while the physiotherapy was delivered in groups). A further study showed that 60% of those who received acupuncture reported less intense pain, compared with 14% who had standard pre-natal care.31 The second systematic review34 focused on randomised trials of needle acupuncture for back pain and PGP in pregnancy and included only three trials (448 women), all from Sweden.28,31,32 The conclusions were similar to the Cochrane Review by Pennick and Young.7 Overall, there was limited, though promising, evidence for the effectiveness of acupuncture. Both systematic reviews highlighted the need for further high-quality trials given the weaknesses in the available evidence. Most previous trials have a moderate to high risk of bias, with unclear randomisation and allocation concealment and lack of full intention-to-treat analyses, and only one trial reported work outcomes, despite these clearly being an important outcome for both pregnant women and society more generally. The one trial with low risk of bias32 focused on Swedish women with PGP at 12–31 weeks’ gestation, and randomised them to standard treatment (information, advice about activities, a pelvic belt and a home exercise programme), standard treatment plus acupuncture (twice per week over 6 weeks using 10 local acupuncture points and seven extrasegmental points with the needles manipulated to evoke a de-qi sensation and left in situ for 30 minutes and stimulated every 10 minutes) or standard treatment plus stabilising exercise (individual stabilising exercises modified for pregnancy for a total of 6 hours over 6 weeks). Since the publication of the two systematic reviews in 2008, a small number of further studies were published. One small pilot study35 found auricular acupuncture to be more effective than either sham acupuncture or a waiting list control. Another further high-quality trial by Elden et al.33 from Sweden compared standard treatment plus acupuncture with standard treatment plus sham (non-penetrating) acupuncture for women with PGP. In that trial, 12 acupuncture treatments were provided over 8 weeks and results showed no differences between groups on pain or sick leave, questioning the importance of needle penetration in the reported beneficial effects of acupuncture. The existing research clearly highlights the need for a high-quality randomised trial in the UK NHS setting, testing the clinical effectiveness and cost-effectiveness of the addition of acupuncture to standard care (SC) for pregnant women with low back pain (with or without PGP). It also highlights the importance of including a sham or non-penetrating acupuncture intervention.
Key methodological issues for the EASE Back study
Given the known limitations of previous trials of acupuncture, we followed published recommendations about methods and reporting trials of acupuncture,36 non-pharmacological interventions37 and sham interventions in trials of physical medicine and rehabilitation23 for our pilot trial. This was informed by the results of our pre-pilot work in phase 1 of the Evaluating Acupuncture and Standard carE for pregnant women with Back pain (EASE Back; a national survey and interviews) study and includes the rationale for acupuncture type, the details of the needling, the intervention protocol, other components of the treatment, practitioner background and experience, full details of the treatments, similar protocols for the true and sham acupuncture treatments and data on participants’ treatment preferences and expectations before they are randomised. There are several key methodological issues relevant to conducting trials of acupuncture (and, more broadly, non-pharmacological interventions for pain); these include sham treatment considerations, issues of blinding, safety, protocolising or standardising what is usually a highly individualised acupuncture treatment for the purposes of a trial and choosing the most appropriate package of SC for comparison. Each of these is discussed along with the implications for the EASE Back study.
Sham acupuncture
A key discussion in the existing research on acupuncture focuses on the challenge of adequate sham or placebo acupuncture treatments.23 In fact, some believe that it is virtually impossible to construct a completely inert placebo that sufficiently mimics the insertion and manipulation of acupuncture needles; hence we use the term ‘sham’. The use of sham intervention helps to ensure participant blinding and reduces the risk of potential bias that can interfere with the observed outcomes.23 We believe that any future large trial should include a treatment group that receives sham acupuncture to enable us to better understand the possible basis of acupuncture effects. Previous trials have used different methods of sham and there is little agreement on the best sham, given that some methods appear to induce physiological effects (e.g. inserting needles at non-acupuncture points or superficial needling at acupuncture points).23 A perfect sham for acupuncture would induce the needle or de-qi sensation,23 but it is increasingly clear that inducing this needling sensation regardless of the stimulation point is associated with the physiological effects of acupuncture. A recent review38 concluded that the effect of acupuncture seems to be unrelated to the type of sham acupuncture used as control and that non-penetrating acupuncture shams are thought to be least likely to have physiological effects. We believe that using non-penetrating needles on a small number of the same acupuncture points that would be used for true acupuncture alongside the inclusion of acupuncture-naive participants are the best solutions to this challenge. Similar approaches have been used successfully in previous trials of acupuncture for musculoskeletal problems39 and pregnant women with PGP.33 Thus, we included three treatment arms in the pilot EASE Back trial: SC, SC plus true acupuncture and SC plus sham acupuncture using non-penetrating needles. The use of sham in trials of acupuncture remains a matter of debate, and some may consider it an ethical dilemma. However, by ensuring that all our pilot trial participants received a package of SC, and that the acupuncture treatment (either true or non-penetrating) was in addition to this SC, we are confident that all participants received appropriate treatment for their pain.
Blinding
A further methodological challenge is the need to ensure adequate blinding: ideally, patients, therapists, outcome assessors and data analysts should be adequately blinded. In a trial of SC and acupuncture, clearly, the therapist cannot be blinded to treatment, but it is possible to blind acupuncture-naive patients to the type of acupuncture (true or non-penetrating), as well as those involved in collecting data and data analysis. Successful blinding has been achieved in a previous trial of acupuncture within the NHS39 and we incorporated this level of blinding into the EASE Back pilot trial. In particular, by gaining ethics approval to explain to potential participants that they would all receive SC and some would receive one of two forms of acupuncture, we were able to ensure that all participants expected to receive good treatment, thus maximising expectation and treatment credibility effects. We included measures of treatment preference and expectation in our pilot trial data set and captured information on treatment credibility at follow-up.
Safety/risks of acupuncture
Despite promising evidence for the effectiveness of acupuncture for relief of back pain and PGP in pregnant women, some clinicians express concerns about safety. One concern is that acupuncture might induce pre-term labour, but available data show this not to be the case. The normal risk of pre-term labour (before 37 weeks’ gestation) is 7–10%. In one of the Swedish trials, Elden et al.40 assessed the adverse effects of acupuncture on the pregnancy, mother, delivery and fetus/neonate. Acupuncture that may be considered strong was used and treatment was started in the second trimester of pregnancy. Adverse effects were recorded during treatment and throughout the pregnancy. The results showed that there were no serious adverse events (SAEs) after any of the treatments, in either babies or mothers. Minor adverse events were common in the acupuncture group, but women rated acupuncture favourably despite this. Therefore, acupuncture administered with a stimulation that may be considered strong led to minor adverse complaints from the mothers and had no observable severe adverse influences on the pregnancy, mother, delivery or fetus/neonate. In addition, acupuncture in early pregnancy (for nausea and vomiting) has been shown to be safe, with no adverse effects on perinatal outcome, congenital abnormalities, pregnancy complications and other infant outcomes.41 In the wider literature, most side effects associated with acupuncture are minor and transient, such as dizziness/light-headedness and slight bleeding after the needles are removed.42 Although there have been reports of fatal events following acupuncture (14 cases in a review of literature over the last 50 years),43 these appear to have been related to cases of clear malpractice and negligence (e.g. as described by Halvorsen et al.44). In the UK, acupuncture training for health professionals, including physiotherapists, is set at a high level, and in trained hands acupuncture is a safe intervention. In our pilot trial in phase 2 of the EASE Back study, the participant information leaflet and consent procedures made the known risks clear and explained the frequency of these risks where these data were available while reassuring pregnant women that even strong acupuncture stimulation has been shown to have no adverse effects on the pregnancy, mother, delivery or developing baby. In addition, the trial design ensured that all women received SC and that acupuncture was in addition to this SC. Therefore, we did not withhold SC from any woman in the EASE Back trial.
Standardising acupuncture treatment for a randomised controlled trial
Since the location and manipulation of the needles in acupuncture are thought to be important in achieving successful outcomes, the therapist usually individualises the treatment for each patient in clinical practice. For the purposes of a trial, however, some degree of standardisation is needed in order to be able to describe the treatment that participants were expected to receive (the intervention protocol) and then to be able to judge whether or not patients received the treatment as expected (protocol adherence). Previous trials of acupuncture have been criticised for lack of clarity about the acupuncture intervention provided as well as for being overly prescriptive with the selection of acupuncture points and needle manipulation to the point that those using acupuncture in clinical practice do not feel that the acupuncture provided in the trial reflects their practice. We believe the best solution to this challenge, for the purposes of a randomised controlled trial (RCT), is to agree a semiflexible acupuncture protocol, in which therapists assess the individual patient’s pain type and location, they palpate for tender points and then they select points from a large number of points that have been agreed to be suitable for inclusion in the protocol (including acupuncture and tender points). This approach has been used successfully in previous trials33,39 ensuring that the acupuncture treatment is individualised, reflecting clinical practice, and that it can be amended over a course of treatment sessions but can also be clearly described in publications.
Copy of the Health Technology Assessment commissioning brief (Health Technology Assessment number 10/69/05)
Question: what is the clinical effectiveness and cost-effectiveness of acupuncture in pregnant women with back pain, in comparison to SC?
Technology: a 6-week acupuncture package, as may plausibly be delivered in the NHS.
Patient group: pregnant women with back pain (including women attending antenatal clinics and outpatients clinics because of back pain).
Control or comparator treatment: sham acupuncture.
Design: a feasibility study to assess the acceptability and design of a trial in the NHS. Methods are likely to include a survey of current practice and qualitative work with clinicians, patients and commissioners. Researchers should identify an appropriate acupuncture intervention and control. They should explore the merits of a sham acupuncture arm.
Important outcomes of main study: pain.
Other outcomes: adverse events, consumption of analgesics, obstetric outcomes, absence from work, functional status, health-related quality of life and cost-effectiveness.
Outcome of the feasibility study: outline plan for a randomised controlled study with evidence supporting its design and delivery.
Minimum duration of follow-up of main study: 6 months after delivery.
Appropriate standard care comparison
The choice of the comparison treatment in acupuncture trials is critically important. Previous trials that compare acupuncture with waiting list controls, ongoing stable medication or minimal care packages tend to show that acupuncture is superior, whereas those that compare acupuncture with more intensive or active interventions have tended to conclude that there are no differences between acupuncture and comparisons.39 We wanted to include a SC comparison that accurately reflected what currently happens in the UK for pregnant women with low back pain. Thus, we followed the recommendations of Ee et al.34 that some form of consensus about treatments for these women is essential to inform clinical trials. Although usual care differs in different services and geographical regions, our interview and survey results from the phase 1 pre-pilot work in the EASE Back study provide the most useful information on which to base a trial protocol for SC. These data ensured that the pilot trial protocol for SC reflected current care in the UK and thus is a fair comparison in the trial.
Rationale for the EASE Back study
A high-quality randomised trial in the NHS is needed to test the clinical effectiveness and cost-effectiveness of adding acupuncture to SC for pregnant women with low back pain (with and without PGP). Before such a large trial can be conducted, however, a feasibility and pilot study was commissioned by the National Institute of Health Research (NIHR) Health Technology Assessment (HTA) programme to inform the design, recruitment, interventions and outcomes. A feasibility study is a research study carried out prior to a main study in order to answer the question ‘Can this study be done?’, and it is used to estimate important parameters needed to design the main study.45 In the EASE Back study we wanted to find out whether or not pregnant women with low back pain would be willing to try acupuncture as a treatment and whether or not they had concerns about acupuncture or being involved in a trial. We also wanted to find out the likely proportions of eligible women from all of the pregnancies overseen by a large maternity centre and whether or not clinicians (community midwives and physiotherapists in particular) would be willing to recruit to, and treat, this patient population in a trial of acupuncture. We needed to test out all the processes of a future main trial and, therefore, the EASE Back study also involved a pilot RCT. A pilot study is a version of the main study run in miniature to test whether or not all the components of the main study can work together.45 The EASE Back pilot RCT therefore tested the inclusion and exclusion criteria, the processes of identification of potentially eligible women, screening and recruitment, randomisation, training of participating research staff and physiotherapists, delivery of treatment, treatment fidelity and credibility of treatment. It allowed us to test whether or not pregnant women with back pain would be willing to be randomised, to test out the outcome measures that might be used in a future main trial, to explore the short-term effects of treatment on these outcomes, to determine short-term follow-up rate, to select a primary outcome measure for a future main trial and to estimate the sample size for a future main trial.
The EASE Back study was a mixed-methods feasibility and pilot study, designed in two phases over 24 months (June 2012 to May 2014), combining survey research (of current practice), qualitative research (focus groups and individual interviews) and a pilot randomised trial with pregnant women with back pain (with and without PGP) with short-term follow-up and audio-recordings of screening and consent meetings with a subsample of women. The results were shared at a dissemination event with stakeholders in May 2014 and consensus achieved about the feasibility and desirability of a main trial. provides a summary of the EASE Back study design.
Summary of the EASE Back study design. AACP, Acupuncture Association of Chartered Physiotherapists; MIMDTP, McKenzie Institute of Mechanical Diagnosis and Therapy Practitioners; NP, non-penetrating.
Overall aim of the EASE Back study
The overall aim of the EASE Back study was to assess the feasibility of a future RCT to test the addition of acupuncture to SC in women with pregnancy-related low back pain.
