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Objective To study the prognosis for pelvic girdle pain, and to explore the association between presence of emotional distress during pregnancy and pelvic girdle syndrome 6 months after delivery.
Design Longitudinal population study.
Setting Norway, for the period 1999–2008.
Population A follow-up of 41 421 women in the Norwegian Mother and Child Cohort who reported pelvic girdle pain at 30 weeks of gestation.
Methods Data were obtained by self-administered questionnaires in weeks 17 and 30 of gestation, and 6 months after delivery.
Main outcome measure Pelvic girdle syndrome 6 months after delivery, defined as pain in the anterior pelvis and on both sides in the posterior pelvis.
Results Six months after delivery, 78.0% of the women had recovered, 18.5% reported persistent pain in one or two pelvic locations, 3.0% reported pelvic girdle syndrome and 0.5% reported severe pelvic girdle syndrome. The recovery rates decreased with increasing levels of pain severity in pregnancy. Being emotionally distressed at two time points during pregnancy was associated with the presence of pelvic girdle syndrome (adjusted OR 1.5, 95% CI 1.2–1.9) and severe pelvic girdle syndrome (adjusted OR 1.9, 95% CI 1.1–3.1), after adjustment for pain severity in pregnancy, other medical conditions, body mass index, age at menarche, previous low back pain, and smoking during pregnancy.
Conclusions In this follow-up of women with pelvic girdle pain in pregnancy, the recovery rates after delivery were high. Our findings suggest that the presence of emotional distress during pregnancy is independently associated with the persistence of pelvic girdle pain after delivery.
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Pelvic girdle pain affects one in five pregnant women, gives rise to functional disability, and is a major cause of sick leave during pregnancy.1,2 Hence, it should be regarded as a major women’s health issue. The reported recovery rates after delivery are high.3 However, in some women, pelvic girdle pain turns into a state of persistent pain and disability,4 and may have substantial individual and socio-economic consequences. The causes and pathogenesis of pregnancy-related pelvic girdle pain remain poorly understood. The diagnosis is based on the woman’s subjective experience, and not from objective findings, and is thus categorized as a subjective health complaint. Nevertheless, the onset of pelvic girdle pain often occurs in the first half of pregnancy,5 and typically resolves shortly after delivery,3 indicating that reproductive factors probably play a significant role.6,7
Although the causes of pelvic girdle pain may differ from the causes of other pain conditions, the factors affecting the recovery process may well have similarities. High pain intensity and the number of pain locations have been indentified as important factors in the transition of acute and subacute pain into chronic pain and disability.8,9 These factors have also been reported to influence the prognosis in pelvic girdle pain.3,10–12 Except for pain severity during pregnancy, knowledge about prognostic factors for pelvic girdle pain is scarce, and most studies have methodological limitations, such as small study samples and/or limitations in design.
Psychological factors are associated with a poor prognosis in other types of musculoskeletal pain.13,14 The direction of the association between psychological factors and chronic pain conditions, however, is debated, leading to calls for longitudinal studies.14,15 It is plausible that psychological factors play a role in the recovery process of pelvic girdle pain, and emotional distress has previously been identified as a risk factor for pelvic girdle pain in pregnancy.7 However, the association of psychological factors with the persistence of pelvic girdle pain after delivery has scarcely been studied, and evidence is inconclusive.10,16–18
In the present study, our aim was to assess the prognosis according to pain severity in 41 421 Norwegian women who reported pelvic girdle pain at 30 weeks of gestation. We also explored the association between the presence of emotional distress during pregnancy and pelvic girdle syndrome (PGS, defined as pain in the anterior pelvis and in the posterior pelvis bilaterally) 6 months after delivery.
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Upon inclusion at 17 weeks of gestation, the mean maternal age was 29.7 years (SD 4.5 years, range 14–46 years). Forty-one percent of the women were first-time mothers, and their mean BMI was 25.4 (SD 4.3). One in five women (21.1%) reported the onset of pelvic girdle pain at 17 weeks of gestation. Emotional distress (SCL-5 ≥ 2.00) at both 17 and 30 weeks of gestation was present in 3.4% of the women, whereas emotional distress at one time point only was present in 8.5%. In women without pelvic girdle pain at 30 weeks of gestation, the corresponding presence of emotional distress was significantly lower, 1.6 and 5.4% (P < 0.001).
Six months after delivery, 22.0% (9099/41 241) of the women reported pain in the pelvic girdle. PGS was present in 3.0% (1252/41 421) and severe PGS was present in 0.5% (196/41 421) of the women (Figure 2). The recovery rate was 82.5% in women reporting pain in one or two pelvic locations at 30 weeks of gestation; it decreased to 68.5% in women reporting PGS and to 45.8% in women reporting severe PGS (Table 1). Nevertheless, 95.0% of women with severe PGS reported an improvement after delivery. The absolute risk of using crutches 6 months after delivery was 5.8% (73/1252) and 29.1% (57/196), respectively, in women with PGS and severe PGS. Likewise, 16.1% (202/1252) of women with PGS and 45.9% (90/196) of women with severe PGS frequently woke up at night 6 months after delivery because of pelvic girdle pain.
Figure 2. Presence of pelvic girdle pain according to subgroups at 30 weeks of gestation and at 6 months postpartum.
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Table 1. Presence of subgroups of pelvic girdle pain 6 months postpartum, according to subgroups at 30 weeks of gestation (n = 41 421)
|Pelvic girdle pain at 30 weeks of gestation||Pelvic girdle pain at 6 months postpartum|
|No pain n (%)||Pain in 1 or 2 locations n (%)||Pain in 3 locations (PGS) n (%)||Severe pain in 3 locations (severe PGS) n (%)|
|Pain in 1 or 2 locations (n = 30 903)||25 505 (82.5)||4932 (16.0)||414 (1.3)||52 (0.2)|
|Pain in 3 locations (n = 8823)||6040 (68.5)||2193 (24.9)||531 (6.0)||59 (0.7)|
|Severe pain in 3 locations (n = 1695)||777 (45.8)||526 (31.0)||307 (18.1)||85 (5.0)|
The presence of emotional distress at one time point during pregnancy was associated with PGS after delivery (crude OR 1.7, 95% CI 1.5–2.0). Likewise, emotional distress at two time points during pregnancy was associated with PGS after delivery (crude OR 2.5, 95% CI 2.0–3.1). The positive association remained after adjustment for potential confounding factors, although the magnitude of the associations was attenuated (adjusted OR 1.3, 95% CI 1.1–1.5, and adjusted OR 1.5, 95% CI 1.2–1.9, respectively; Table 2). Emotional distress at one or both time points during pregnancy was also significantly associated with severe PGS after delivery (crude OR 2.6, 95% CI 1.8–3.9, and crude OR 3.5, 95% CI 2.1–5.9, respectively). After adjustment, the corresponding odds ratios were attenuated, but the positive associations remained (adjusted OR 2.0, 95% CI 1.4–2.9, and adjusted OR 1.9, 95% CI 1.1–3.1, respectively; Table 2). Pain severity at 30 weeks of gestation and the co-morbidity index were the main confounding factors of the associations, but no interactions between these factors and emotional distress regarding the risk of PGS or severe PGS were identified. The associations between emotional distress during pregnancy and PGS were also present in analyses restricted to women with onset of pelvic girdle pain after 17 weeks of gestation (Table 3).
Table 2. Prognostic factors for pelvic girdle syndrome and severe pelvic girdle syndrome at 6 months postpartum (n = 41 421)
|Variables|| n ||Pelvic girdle syndrome||Severe pelvic girdle syndrome|
|Cases (%)||Adjusted OR (95% CI)||Cases (%)||Adjusted OR (95% CI)|
| Emotional distress |
|No||36 517||1161 (3.2)||1.0||140 (0.4)||1.0|
|Yes, at one time point||3512||187 (5.3)||1.3 (1.1–1.5)**||38 (1.1)||2.0 (1.4–2.9)***|
|Yes, at two time points||1392||100 (7.2)||1.5 (1.2–1.9)***||18 (1.3)||1.9 (1.1–3.1)*|
| Level of severity in pregnancy |
|Pain in 1 or 2 locations||30 903||466 (1.5)||1.0||52 (0.2)||1.0|
|Pain in 3 locations||8823||590 (6.7)||4.2 (3.7–4.8)***||59 (0.7)||3.5 (2.4–5.1)***|
|Severe pain in 3 locations||1695||392 (23.1)||16.3 (14.0–18.9)***||85 (5.0)||24.0 (16.8–34.3)***|
| Co-morbidity index |
|No diseases||11 075||235 (2.1)||1.0||31 (0.3)||1.0|
|1 disease||14 238||425 (3.0)||1.3 (1.1–1.6)**||54 (0.4)||1.2 (0.8–1.9)|
|2–3 diseases||14 018||625 (4.5)||1.8 (1.5–2.1)***||84 (0.6)||1.6 (1.1–2.5)*|
|≥4 diseases||2090||163 (7.8)||2.4 (1.9–3.0)***||27 (1.3)||2.3 (1.3–3.9)**|
| BMI at inclusion (kg/m2)|
|<25||21 576||588 (2.7)||1.0||72 (0.3)||1.0|
|25–29||12 527||450 (3.6)||1.1 (1.0–1.3)||60 (0.5)||1.1 (0.7–1.5)|
|≥30||5449||353 (6.5)||1.8 (1.5–2.0)***||52 (1.0)||1.6 (1.1–2.4)*|
|Missing||1869||57 (3.0)||1.0 (0.8–1.4)||12 (0.6)||1.6 (0.9–3.1)|
| Age at menarche (years)|
|≤10||982||62 (6.3)||1.3 (1.0–1.8)*||17 (1.7)||3.1 (1.8–5.3)***|
|11||4239||198 (4.7)||1.2 (1.0–1.4)*||33 (0.8)||1.7 (1.2–2.6)**|
|12||10 592||396 (3.7)||1.1 (0.9–1.2)||58 (0.5)||1.4 (1.0–2.0)*|
|≥13||25 144||780 (3.1)||1.0||86 (0.3)||1.0|
|Missing||464||12 (2.6)||0.8 (0.4–1.5)||2 (0.4)||1.2 (0.3–4.9)|
| Previous low back pain |
|No||32 215||941 (2.9)||1.0||126 (0.4)||1.0|
|Yes||9206||507 (5.5)||1.5 (1.4–1.7)***||70 (0.8)||1.4 (1.0–1.9)*|
| Smoking during pregnancy |
|Non-smoker||36 930||1244 (3.4)||1.0||168 (0.5)||1.0|
|Occasional smoker||1935||98 (5.1)||1.3 (1.0–1.6)*||10 (0.5)||0.7 (0.4–1.5)|
|Daily smoker||1926||90 (4.7)||1.0 (0.8–1.3)||15 (0.8)||1.2 (0.7–2.1)|
|Missing||630||16 (2.5)||0.8 (0.5–1.3)||3 (0.5)||1.1 (0.4–3.7)|
Table 3. The associations of emotional distress with pelvic girdle syndrome and severe pelvic girdle syndrome at 6 months postpartum in 32 680 women with onset of pelvic girdle pain after 17 weeks of gestation
| || n ||Pelvic girdle syndrome||Severe pelvic girdle syndrome|
|Cases (%)||Adjusted OR (95% CI)||Cases (%)||Adjusted OR (95% CI)|
| Emotional distress |
|No||28 966||556 (1.9)||1.0||61 (0.2)||1.0|
|Yes, at one time point||2671||91 (3.4)||1.4 (1.1–1.7)**||18 (0.7)||2.3 (1.3–4.0)**|
|Yes, at two time points||1043||54 (5.2)||1.9 (1.4–2.6)***||8 (0.8)||2.3 (1.1–4.9)*|
The level of pain severity at 30 weeks of gestation was the strongest prognostic factor (Table 2). The adjusted ORs for reporting PGS after delivery were 4.2 (95% CI 3.7–4.8) and 16.3 (95% CI 14.0–18.9) in women who reported pain in three locations and severe pain in three locations, respectively, at 30 weeks of gestation, as compared with the reference group. Other factors associated with PGS were a high co-morbidity index, early menarche, BMI ≥ 30, previous low back pain, and occasional smoking during pregnancy. All of these factors, with the exception of smoking, were also associated with severe PGS (Table 2). Accordingly, a high level of pain severity at 30 weeks of gestation was the strongest predictor for severe PGS after delivery, but early menarche and a high co-morbidity index were also strongly associated with severe PGS. Maternal age, number of deliveries, and educational level were not important confounding factors of the associations of emotional distress with PGS, nor were they associated with the outcomes, and were not included in the final models.
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In this follow-up study of 41 421 pregnant women reporting pelvic girdle pain in pregnancy, 78.0% had recovered 6 months after delivery. Nevertheless, 3.5% of the women still reported significant complaints. The recovery rates decreased with increasing levels of pain severity at pregnancy week 30. Women who experienced emotional distress during pregnancy were at an increased risk of reporting PGS after delivery, even after adjustment for pain severity.
In accordance with previous studies, the recovery rates of pelvic girdle pain were high, and the risk of non-recovery increased with pain severity in pregnancy.3,11,17 A previous study has reported a substantially poorer prognosis in women with PGS compared with other subgroups.3 A poorer prognosis has also been found in women with combined low back and pelvic girdle pain, than in women with either low back pain or pelvic girdle pain.11
An association between depressive symptoms and pelvic girdle pain after delivery has previously been reported in a cross-sectional study.16 For a better understanding of the nexus of cause and effect between psychological factors and chronic pain, longitudinal studies are needed.14,15 Only three previous longitudinal studies have assessed the association between emotional distress and persistence of pelvic girdle pain, finding none.10,17,18 The lack of a significant association in these studies may be explained by methodological limitations, such as low statistical power or insufficient control for confounding. To our knowledge, this longitudinal study is the first to confirm an association between the presence of emotional distress during pregnancy and persistent pelvic girdle pain in a large population that enabled control for several confounding factors.
Although we used a longitudinal design and measured emotional distress at two time points during pregnancy, we cannot rule out bidirectional causality. It is likely that the presence of pain during pregnancy induced increased levels of emotional distress. Nevertheless, the association between emotional distress during pregnancy and PGS after delivery was also present in women who did not report pain at the first measurement point of emotional distress at 17 weeks of gestation. In the analyses, we adjusted for several potential confounding factors, including the level of pain severity in pregnancy and co-morbidity, but the effect of emotional distress on PGS remained, suggesting a true relationship. It is also possible that PGS at 6 months after delivery has been over-reported by women with high levels of emotional distress. Therefore, it may be argued that the analyses should be adjusted for emotional distress 6 months after delivery. We performed additional analyses, adjusting for emotional distress after delivery, but the results remained the same (data not shown). However, adjusting for emotional distress at the end point may lead to over-adjustment because persistence of pain may have affected the level of emotional distress after delivery.
The location and intensity of pelvic girdle pain were based on self-reports and not on clinical examination. Self-reports of pelvic girdle pain have been reported to correlate well with the number of positive clinical tests.27 Even though attempts have been made,1 there is no international gold standard for clinical signs and symptoms that should result in a diagnosis of pelvic girdle pain. To ensure that the outcome measure had high specificity for pelvic girdle pain, we used pain in the anterior pelvis and on both sides in the posterior pelvis as our outcome. This subgroup has been associated with greater functional disability, more frequent sick leave, and significantly worse prognosis than pain in one or two pelvic locations.2,3,28 Furthermore, it has previously been shown that the number of pain sites has a strong predictor utility.9 This strengthens our classification of severity level during pregnancy, which was based on pain intensity, pain location, and the number of pain sites.
In the Norwegian Mother and Child Cohort Study, the women’s answers to SCL-5 were the only available measure of mental health. Generally, questionnaire studies enable the evaluation of larger study populations than studies using clinical interviews for data collection. A clinical interview, however, remains the gold standard for assessing emotional distress. It is important to note that SCL-5 cannot be used for diagnosing depression, anxiety, or other psychiatric disorders. The advantage of using SCL is that it is designed to measure symptoms of anxiety and depression in population surveys.20–22 It has been validated in several populations and is documented as an acceptable screening instrument for depression, as defined by the ICD-10.23,24 Furthermore, the presence of emotional distress at two time points during pregnancy is likely to have a higher specificity for emotional distress than the presence of emotional distress at one time point only.
The participation rate in the Norwegian Mother and Child Cohort Study was rather low, which is a common problem in large epidemiological studies.29 A low participation rate may result in skewed selection of participants and affect the prevalence estimates of the disease under study. However, the exposure–disease associations are more robust to selection bias than the prevalence estimates.29,30 A recent study on the potential biases of skewed selection in the Norwegian Mother and Child Cohort found the prevalence estimates, but not the exposure–disease associations, to be influenced by the selection.30 Compared with the general pregnant population in Norway, first-time mothers and women with a high socio-economic status were over-represented, whereas young mothers were under-represented. In a previous study, we found that the number of previous deliveries, a low educational level, and young maternal age were independent risk factors for pelvic girdle pain in pregnancy.7 Hence, the women included in our study sample may not be representative for the general population because the prevalence of pelvic girdle pain may have been underestimated. The women lost to follow-up after delivery had higher levels of emotional distress and reported more pelvic girdle pain at 30 weeks of gestation than the women making up our study sample. Consequently, our estimated recovery rates may have been overestimated, whereas the estimated association of emotional distress with PGS may have been underestimated as a result of selective attrition, although the direction of the association is not likely to be biased.30 Random errors associated with imprecise reporting may also have deflated the estimated association. On the other hand, this is probably counteracted because women with high levels of emotional distress during pregnancy may be more prone to report pain symptoms.
In the present study, women experiencing emotional distress during pregnancy were at an increased risk of reporting PGS 6 months after delivery. This finding may be explained by cognitive, behavioural, and neurophysiological factors.31 Emotionally distressed women may have an increased awareness of pain symptoms,32 and their interpretation of pain may differ from that of women without emotional distress. Patients with depression are more likely to catastrophize about pain.33 Thus, pain in emotionally distressed women may promote adaptation of dysfunctional movement patterns, physical inactivity, and hinder participation in social activities. Such behaviour may further increase the risk of chronic pain. Depression has also been suggested to promote central sensitisation and to influence endogenous pain inhibition,31 mechanisms likely to interfere with the recovery process of pelvic girdle pain. Furthermore, dysfunctions of the hypothalamic–pituitary–adrenal axis may represent a link between emotional distress and the persistence of pain.34
Although emotional distress during pregnancy affected the recovery process of PGS in our study, the level of pain severity in pregnancy was the most important prognostic factor. High pain intensity and a high number of pain sites during pregnancy and the postpartum period may cause central sensitisation,35 and increase the risk of persistent pain.36 In contrast, an increased risk of persistence of pain after delivery may result from individual differences in pain sensitivity. Most pain conditions are associated with an increased sensitivity to pain, with typically little correspondence between pathological findings and reported pain.37,38 Hence, normal changes in the pelvic girdle may be perceived as painful only in women with increased pain sensitivity. An influence of central pain mechanisms in the persistence of pelvic girdle pain is supported by the associations with a high co-morbidity index and previous low back pain. The increased risk of non-recovery in women with high co-morbidity is supported by a previous study.17 We also found associations of high BMI and early menarche with the presence of PGS after delivery. Obese women and women with early menarche have higher morbidity and mortality,39,40 and the increased risk of disease may be linked to hormonal and metabolic factors. Such factors are also likely to be associated with pelvic girdle pain. Therefore, women with persistent pelvic girdle pain may represent a group more susceptible to disease than the general female population.