Review written by: Dr. Ceara Higgins (for RRS Education)
Title: Can a bothersome course of pelvic pain from mid-pregnancy to birth be predicted? A Norwegian prospective longitudinal SMS-Track study
Authors: Malmqvist S, Kjaermann I, Andersen K, et al.
Publication Information: BMJ Open 2018; 8: e021378. doi:10.1136/bmjopen-2017-021378.
Introduction
Approximately half of pregnant women will experience pelvic girdle pain (PGP) during their pregnancy, with 25%-30% experiencing severe pain. The exact etiology of PGP is unknown; however, it is known to lead to pain-related restrictions on physical activity during and after childbirth, and to have a psychological impact on their perceived health, sexual life and general quality of life. PGP is classified as specific (caused by trauma) or non-specific (multifactorial) and is diagnosed through physical examination. To date, no gold-standard testing exists for the diagnosis of PGP, although the posterior pelvic pain provocation test (P4) for sacroiliac joint dysfunction and the active straight leg raise test (ASLR) for detecting failing force closure have both shown high levels of validity and reliability (both described in methods section below).1
Existing prospective studies on PGP have generally collected data at baseline and at one or two follow-up points, limiting the total amount of data available for analysis. More frequent data collection may allow for a more accurate description of the clinical course of PGP during pregnancy. Collection of longitudinal data through text messages has been shown to be feasible in clinical settings3 and allows for the collection of a much greater data pool. The authors of this study aimed to explore the differences in demographics and clinical characteristics at mid-pregnancy and the weekly amount of days with bothersome symptoms throughout the second half of pregnancy in women sub-grouped based on the results of two valid and reliable clinical tests (P4 and ASLR) at 18 weeks of pregnancy. The authors hypothesized that sacroiliac dysfunction and failing force closure diagnosed at mid-pregnancy could be used to predict a course of bothersome symptoms throughout the second half of pregnancy.
Pertinent Results
503 women were included in the study. Of these, 42% reported pain in the lumbopelvic region. On clinical examination, 39% fulfilled the criteria for a probable PGP diagnosis and 27% had positive findings on both the ASLR and P4 tests. Those women reporting pelvic pain but having no positive clinical findings were placed in the ASLR and P4 negative group.
Demographically, women with positive ASLR and P4 tests had a heavier workload, higher BMI at week 18 and exercised less both before and during pregnancy. Further, just over 1/3 of these women reported feelings of depression during their pregnancy, and almost half had required sick leave during their pregnancy. These women also showed higher levels of physical disability and pain at week 18 than women reporting pain but having negative ASLR and P4 tests. Women with positive ASLR and negative P4 had the highest number of previous pregnancies.
The SMS-Track response rate was 75%, with a decline in response seen at the end of the pregnancy. As a result, the authors stopped their data analysis at week 38 (it would have been very interesting if they were able to collect data after delivery).
Women who showed both positive P4 and ASLR tests reported a high weekly average number of days (five days/week) with bothersome pelvic pain throughout their pregnancies. Women who had both tests negative showed a steady rise in the number of bothersome days, from 0.5 days/week at week 18 to two days/week in week 37. The group with a positive P4 and negative ASLR only showed three bothersome days/week at week 18, but this rapidly increased to match the group with both positive tests from week 29 onward. The group with a positive ASLR and negative P4 also showed three bothersome days/week at 18 weeks, but never reached the level of the group with both tests positive.
Overall, the estimated rate for experiencing bothersome days was 7.5 times higher in women with both ASLR and P4 positive and 1.5 times higher in women with either a positive ASLR or positive P4 when compared to women with both tests negative.
For every additional previous pregnancy, the mean number of bothersome days increased by 13.5% and even slight increases in BMI significantly increased the number of bothersome days, while age had no impact.
Demographic data also showed that women with the highest number of previous pregnancies and highest mean rate of PGP in previous pregnancies also exercised more frequently, both before and during the current pregnancy, than women in the other positive test groups. This may be because they have found exercise to be beneficial for improving muscle activation, recovering function, and decreasing pain4 during previous pregnancies. Finally, women who were able to control their work situation showed better health overall during their pregnancy than women without any ability to control their work situation.
Clinical Application and Conclusions
If a clinical examination in mid-pregnancy shows both positive ASLR and P4 tests, it is possible to predict a course of bothersome PGP for more than five days per week throughout the pregnancy. The number of predicted days of bothersome PGP can be expected to increase for every added pregnancy but may be decreased by individual control over work situation and regular exercise through a positive impact on optimal force closure of the pelvis, reduced risk of instability in the pelvic joints, and enhanced overall well-being. The results of this study allow clinicians to better identify women at risk of bothersome pelvic pain, which can allow proper tailoring of both treatment and exercise interventions.
Further research is still needed to identify the gold standard for diagnosing PGP, but at the very least, clinicians should employ the ASLR and P4 tests.
Study Methods
The authors preformed a prospective, longitudinal cohort study of pregnant women from the obstetric outpatient clinic at Stavanger University Hospital in Norway who received their 18-week ultrasound examination between mid-March and mid-June 2010. Midwives screened patients using inclusion criteria of current lumbopelvic pain or isolated pelvic pain, singleton (single fetus) pregnancy, and proficiency in the Norwegian language. Women meeting these criteria were told about the study, given a letter of consent to fill in if interested in participating, and an envelope containing questionnaires on demographics and clinical data (including pain intensity rated on a numerical rating scale from 0 = no pain to 100 = unbearable pain, the Oswestry Disability Index to evaluate disability, a scale from the Stockholm Public Health questionnaire to measure physical workload from sedentary to heavy, and a five-point Likert scale from very bad to very good to evaluate job satisfaction) to complete at home. They were then booked to see a chiropractor for a physical examination and asked to bring the completed questionnaires to that consultation. Women without pain who met the other criteria were told about the study and given the same letter of consent and the questionnaire on demographic data to complete and leave at reception.
Clinical Testing Procedures:
Women in the pain group saw one of two chiropractors for a physical examination of the pelvic region including diagnostic tests recommended by the European guidelines for the diagnosis and treatment of PGP and a lower extremity neurological examination.
This testing included the ASLR, where the patient was placed supine with their legs straight and feet 20 cm apart. The patient was then instructed to try to raise their legs, one after another, above the couch to about 20 cm without bending their knees. The patient was then asked to score their impairment on a six-point scale: 0 = not difficult at all; 1 = minimally difficult; 2 = somewhat difficult;3 = difficult; 4 = very difficult; 5 = unable to do. Scores from both sides were then added to give a total score from 0-10.2 The other important test performed was the posterior pelvic pain provocation test (P4), where the patient was placed in a supine position with the hip on the side to be examined flexed to 90 degrees. The examiner then applied a light manual pressure to the patient’s flexed knee along the longitudinal axis of the femur while using the other hand to stabilize the patient’s pelvis by resting it on the patient’s contralateral superior anterior iliac spine. The P4 test is considered positive if the patient feels a familiar, well localized pain deep in the gluteal area of the provoked side. Additional testing included Gaenslen’s test, Long dorsal sacroiliac ligament test (palpation in side-lying), modified Trendelenburg’s test, Patrick’s FABER test, and the symphysis palpation test (note, these test results were not utilized in the predictive model).
All consenting women received weekly, automated text messages (SMS-Track) on Sundays from 18 weeks of pregnancy through birth. They were asked how many days in the previous week they had experienced bothersome pelvic pain. If there was no reply, the question was repeated 24 hours later. Responses were automatically entered into a database.
Study Strengths / Weaknesses
Strengths:
- The use of text messages to collect data resulted in a high response rate, allowing for a large data pool.
- Having responses immediately recorded in a datasheet minimized data handling and risk of human error.
Weaknesses:
- The retrospective collection of information on pain during previous pregnancies and pain before pregnancy may have produced biased results.
- The researchers had trouble reaching women through some mobile phone service providers, which led to some missing data.
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Additional References:
- Gutke A, Hansson ER, Zetherstrom G, et al. Posterior pelvic pain provocation test is negative in patients with lumbar herniated discs. Eur Spine J 2009; 18: 1008-1012.
- Mens JM, Vleeming A, Snijders CJ, et al. Reliability and vaidity of the active straight leg raise test in posterior pelvic pain since pregnancy. Spine 2001; 26: 1167-1171.
- Axen I, Bodin L, Bergstrom G, et al. The use of weekly text messaging over 6 months was a feasible method for monitoring the clinical course of low back pain in patients seeking chiropractic care. J Clin Epidemiol 2012; 65: 454-461.
- O’Sullivan PB, Beales DJ. Diagnosis and classification of pelvic girdle pain disorders—Part 1: a mechanism-based approach within a biopsychosocial framework. Man Ther 2007; 12: 86-97.
