Journal of Womens Health, Issues and Care ISSN: 2325-9795

All submissions of the EM system will be redirected to Online Manuscript Submission System. Authors are requested to submit articles directly to Online Manuscript Submission System of respective journal.

Research Article, J Womens Health Issues Care Vol: 5 Issue: 2

Physiological Evaluation of Neck and Shoulder Pain (Katakori in Japanese) in Postpartum Japanese Women

Keiko Koyasu1*, Naomi Ueyama2, Yuko Tanikawa3, Mineo Yamasaki4 and Hiroya Matsuo5
1Kansai University of Nursing and Health Sciences, Awaji, Japan
2Takarazuka University School of Nursing, Osaka, Japan
3Takenoko midwifery center, Kobe, Japan
4Palmore Hospital, Kobe, Japan
5Kobe University Graduate School of Health Sciences, Kobe, Japan
Corresponding author : Keiko Koyasu
Kansai University of Nursing and Health Sciences, 1456-4 Shizuki Awaji, Hyogo, 656-2131, Japan
Tel:
+81-799-60-120
E-mail: [email protected]
Received: March 09, 2016 Accepted: March 22, 2016 Published: March 27, 2016
Citation: Koyasu K, Ueyama N, Tanikawa Y, Yamasaki M, Matsuo H (2016) Physiological Evaluation of Neck and Shoulder Pain (Katakori in Japanese) in Postpartum Japanese Women. J Womens Health, Issues Care 5:2. doi:10.4172/2325-9795.1000224

Abstract

Objective: Neck and shoulder pain (NSP) is the most common symptom in Japanese women. NSP is often accompanied by unpleasant symptoms. The objective of this study is to elucidate the pathophysiology of NSP in relation to specific mental and physical states in postpartum women.
Methods: Data was collected by questionnaire, It consisted of the subject’s characteristics, details of NSP and degree disturbance of daily life due to NSP (level 0 (none) to 10). Evaluation of psychological stress was using the Profile of Mood States - Brief Japanese version (POMS-B). Moreover, we examined measurement of muscle hardness, blood flow, autonomic nervous system (ANS) activity and angles of breastfeeding posture. Participants were 62 postpartum women from one month to six months after delivery.
Results: The worsening of NSP after birth was associated with psychological distress by POMS-B. ANS activity was compared with “less than 25% of the quartile” and “more than 75% of the quartile” of POMS-B score, using t-test. High-Frequency (HF) tended to be lower in “more than 75%” than in “less than 25%” score for Fatigue. The mean score of “disturbance of daily life due to NSP” in postpartum women with NSP was 4.7±2.3. The surface skin temperatures in “disturbance of daily life due to NSP ? 4.7” were significantly lower than those in “< 4.7”. LF/ HF ratio in “? 4.7” was significantly higher than that in “< 4.7”. Breastfeeding posture angles showed significant differences in head angle between “worse after birth” and “no-change/relief after birth”.
Conclusions: The results suggested that psychological stress in postpartum women might be related to worsening of NSP through the modification of ANS activity and worsening of NSP after birth was associated with breastfeeding posture.

Keywords: Neck and shoulder pain; Postpartum women; Psychological state; Breastfeeding posture; Autonomic nervous system (ANS) activity

Keywords

Neck and shoulder pain; Postpartum women; Psychological state; Breastfeeding posture; Autonomic nervous system (ANS) activity

Introduction

Neck and shoulder pain (NSP) is the most common symptom experienced by Japanese women according to a comprehensive survey of living conditions conducted by the Ministry of Health, Labour and Welfare in 2010 [1]. NSP is often accompanied by unpleasant symptoms, which result in the reduction of QOL [2]. On the other hand, postpartum women are in a psychologically stressful condition [3,4]. Moreover there is a possibility that specific postures during breastfeeding may increase load on the shoulders, resulting in NSP. We have reported that the prevalence of NSP at one month after delivery in postpartum Japanese women was 78% and its related factors might be breastfeeding, mental states such as anxiety and tension, and past history of premenstrual syndrome (PMS). Particularly, breastfeeding was identified as one of the daily living activities which worsen NSP in postpartum women [5]. It is speculated that NSP in postpartum women may be superimposed by specific physical and mental states in the postpartum period.However, there is lack of reports on the pathophysiology of the inducement and the worsening of NSP by specific states in postpartum women. Therefore, to elucidate the pathophysiology of NSP in relation to specific mental and physical states in postpartum women, we measured muscle hardness, blood flow, autonomic nervous system (ANS) activity and angles of breastfeeding posture.

Methods

Subjects
This study was conducted at two obstetrical hospitals in Kobe city, during April 2012 and February 2013. Subjects were postpartum women from one month to six months after delivery with term birth, excluded if they had orthopedic diseases. The purpose, methods and risks of this study were explained to the subjects who visited the hospitals for medical checkups one month after delivery or seminar attendance (baby massage). The following examinations were conducted for the women who consented to this study.
This study was approved by the Ethics Committee of Kobe University Graduate School of Health Sciences.
Method
Self-administered questionnaire
The questionnaire consisted of the subject’s characteristics and details of NSP and breastfeeding. Characteristics included age, height, history of previous pregnancy, weight, period after birth, mode of delivery, anemia during pregnancy and after delivery, past history of premenstrual syndrome (PMS) and Hiesho, and supports. Concerning NSP present history, onset (before and during pregnancy, after birth, other), change after birth (five levels: worse, slightly worse, no change, a little relief, relief), daily living activities which worsen NSP, and degree disturbance of daily life due to NSP (level 0 (none) to 10) were examined. On breastfeeding methods (breastfeeding only, breastfeeding and bottle-feeding, bottle-feeding only), posture during nursing, frequency and duration of breastfeeding were examined.
Evaluation of psychological stress
Psychological stress was evaluated using the Profile of Mood States - Brief Japanese version (POMS-B). POMS-B consists of into six mood states (30-items): “Tension-Anxiety” (T-A), “Depression” (D), “Anger-Hostility” (A-H), Fatigue” (F), “Vigor” (V), and “Confusion” (C). POMS-B is able to measure temporary changes in feeling according to the condition. The subjects responded concerning each items on her mood over the past one week. The answer to each questions was described using a 5-point scale : not at all, a little, moderately, quite a bit or extremely. A score of 0 to 4 was then assigned to each answer. The scores were the sums of the items in each mood state and these were calculated as a T-score. T-score = 50+10×(score‐mean) / SD.
Physiological evaluations
The measurements were conducted in a quiet environment at between 23 and 25 degrees centigrade. To avoid the influence of room temperature on the measurement, we maintained the same conditions for at least 20 minutes before the measurements.
Muscle hardness of the shoulder: Muscle hardness data were obtained from both shoulders of each subject (at the midpoint between the acromion and seventh cervical vertebra (C7) spinous process (SP)) using a Tissue Hardness Meter (PEK-1, Imoto Machinery Co., Ltd, Kyoto, Japan). The measurements were conducted three times and the mean value was assessed as muscle hardness.
Blood flow of the shoulder: Surface skin temperatures were measured using a Radiation Thermometer (IT-550, Horiba, Ltd., Kyoto, Japan) and Thermography (FLIRi5, FLIR Systems, Tokyo, Japan). The points of the temperature measurements using the Radiation Thermometer were at the midpoint between the acromion and the C7 SP. The measurements were conducted three times and the mean value was assessed as blood flow. The area of measurement using Thermography was the upper part of the back (from both armpits to both shoulders). The data were transferred to a notebook computer using the Therma CAMTM Quick Report software (FLIR Systems Japan K.K, Tokyo, Japan) and analyzed with it (maximum, minimum and mean temperatures).
Autonomic nervous system (ANS) activity: ANS activity was assessed as heart rate variability. After a few minutes of supine rest, recordings were obtained from immobile participants using a Model FX7302 ECG (Fukuda Denshi Inc., Kobe, Japan) for 2 minutes without conversation in a quiet environment at 25°C. We performed frequency analysis using the Lab VIEW fast fourier transformation program (National Instruments Corporation, Kobe, Japan) and calculated the low-frequency (LF, 0.04~0.15Hz) and high-frequency(HF>0.15Hz) components from the data. LF is considered to be a marker of both sympathetic and parasympathetic modulation. HF is generally defined as marker of parasympathetic modulation. The ration between the powers of the LF and the HF components (LF/HF ratio) was used to evaluate sympathetic nerve activity.
Evaluation of the breastfeeding posture
The angles of breastfeeding posture were measured using photographs from lateral, above and front of the subject. Participants changed their clothes to shirts which fitted their bodies and were instructed to sit in their usual breastfeeding posture. Reflective markers were placed on their acromion, elbow and earlobe. Image J Japanese version (Lisit, Co., Ltd, Tokyo, Japan) was used to measure the following angles as shown in Figure 1, ① C7 SP angle;between the C7 SP and the vertical line, ② Shoulder angle;between the acromion and the vertical line, ③ Head angle;between the occiput and the vertical line, a vertical line was drawn through the subject’s buttock grounded on the floor, ④ Shoulders rotation; the left acromion and the horizontal line through the right acromion, ⑤ Shoulder tilt; between the left acromion and the horizontal line through the right acromion, ⑥ Head tilt; between the midpoint of the forehead and the horizontal line through the right acromion.
Figure 1: Illustration of breastfeeding postural angles
Arrows indicate the angles measured. Dashed lines indicate the vertical or horizontal.
①C7 SP angle, ②Shoulder angle, ③Head angle, ④Shoulders rotation (Above),⑤Shoulder tilt (Front),⑥Head tilt (Front)
The results were compared among three groups: with NSP and without NSP, worse after birth (worse, slightly worse) and no-change/ relief after birth (no change, a little relief, relief), and more than and less than mean score of “ disturbance of daily life due to NSP”.
Statistics
The differences in background, POMS-B score and measured values among the three groups were tested using the t-test. Moreover the association between POMS-B score and ANS activity was also analyzed. ANS activity was compared with “less than 25% of the quartile” and “more than 75% of the quartile” of POMS-B score, using t-test. Statistical significance was expressed as p values at 95% confidence intervals. All statistical analyses were carried out using SPSS for Windows(20J).

Results

Characteristics of subjects
Table 1 shows the subject characteristics. The mean of days after delivery was 66.0 ± 31.8 (28-143 days). The percentages of primipara and multipara were 77.4% (48/62) and 22.6% (14/62). Concerning the mode of breastfeeding, breastfeeding only, breastfeeding and bottle-feeding, and bottle-feeding only were 85.5% (53/62), 14.5% (9/62), and 0.0% (0/0), respectively.
Table 1: Subject characteristics
Prevalence and present history of NSP in postpartum women
The prevalence of NSP in postpartum women was 85.5%(53/62). Onset of NSP was categorized into four categories: before pregnancy, during pregnancy, after birth and the others. These were 66.0% (35/53), 0.0% (0/53), 26.4% (14/53) and 7.5% (4/53), respectively. Change of NSP after birth: “Worse” and “slightly worse” were 41.5% (22/53), “no change” 43.4% (23/53), “a little relief” 9.4% (5/53) and “relief” 5.7% (3/53).
NSP and daily living activities in postpartum women
The mean score of “disturbance of daily life due to NSP” in postpartum women with NSP was 4.7 ± 2.3 (Figure 2A). The frequently daily living activities which worsen NSP were breastfeeding 66.0% (35/53), holding the baby 56.6% (30/53), and using a personal computer 34.0% (18/53) (Figure 2B).
Figure 2a: Disturbance of daily life due to NSP in postpartum women.
Figure 2b: Disturbance of daily life due to NSP in postpartum women.
Psychological evaluation on NSP in postpartum women
Regarding the T-scores of POMS-B, the mean score for F was significantly higher in “with NSP” than in “without NSP” (p=0.044). But there were no significant differences in the mean score for T-A, D, A-H, V and C between the groups. On the change of NSP after birth, the mean score for T-A was significantly higher in “worse after birth” than in “no-change/relief after birth” (p=0.009). And the mean score for C tended to be higher in “worse after birth” than in “no-change/ relief after birth” (p=0.068). The mean scores for A-H and F in “disturbance of daily life due to NSP ≧ 4.7” were significantly higher than those in “disturbance of daily life due to NSP < 4.7”(p=0.047, p=0.017) (Table 2).
Table 2: Neck and shoulder pain (NSP) and the Profile of Mood State Brief(POMS-B) scores in postpartum women.
Psychological state and ANS activity
HF tended to be lower in “more than 75% of the quartile” than in “less than 25% of the quartile” score for F (p=0.085). There were no significant differences between “more than 75% of the quartile” than in “less than 25% of the quartile” for T-A, D, A-H, V and C (Table 3).
Table 3: Psychological state and autonomic nervous system (ANS) activity in postpartum women.
Physiological evaluation on NSP in postpartum women
Table 4 shows the results of shoulder muscle hardness, surface skin temperature and ANS activity in postpartum women. Concerning the mean score of “disturbance of daily life due to NSP”, the mean and maximum surface skin temperatures in “disturbance of daily life due to NSP ≧ 4.7” were significantly lower than those in “disturbance of daily life due to NSP < 4.7” (p=0.042, p=0.024). LF/HF ratio in “disturbance of daily life due to NSP ≧ 4.7” was significantly higher than that in “disturbance of daily life due to NSP < 4.7” (p=0.042). HF tended to be lower in “disturbance of daily life due to NSP ≧ 4.7” than in “disturbance of daily life due to NSP < 4.7” (p=0.077). As for muscle hardness and surface skin temperatures by radiation thermometer, there were no significant differences between “disturbance of daily life due to NSP ≧ 4.7” and “disturbance of daily life due to NSP < 4.7”.
Table 4: Neck and shoulder pain(NSP) and the physiological measurements in postpartum women.
The effect of breastfeeding posture on NSP in postpartum women
We evaluated breastfeeding posture by six angles (C7 SP, shoulder, head, shoulders rotation, shoulder tilt and head tilt), shown in Figure 1. The mean head angle of “worse after birth” was 15.3 ± 5.2 degree and that of “no-change/relief after birth” was 11.6 ± 4.9 degree. There were significant differences in the angle between “worse after birth” and “no-change/relief after birth” (p=0.019). The mean shoulder angle and head angle in “disturbance of daily life due to NSP ≧ 4.7” were significant larger than those in “disturbance of daily life due to NSP < 4.7” (p=0.030,p=0.044) and the mean angle of C7 SP in “disturbance of daily life due to NSP ≧ 4.7” tended to be larger than that in “disturbance of daily life due to NSP < 4.7”(p=0.077). There were no significant difference in the angles of shoulders rotation, shoulder tilt and head tilt between “disturbance of daily life due to NSP ≧ 4.7” and “disturbance of daily life due to NSP < 4.7” (Table 5).
Table 5: The angles of breastfeeding posture and neck and shoulder pain(NSP) in postpartum women

Discussion

We reported that breastfeeding was one of the most common daily living activities which worsen NSP after birth, and that psychological stress might be associated with NSP after birth [5]. In this study, to evaluate the pathophysiology of NSP in relation to the specific mental and physical states after birth, we examined muscle hardness, blood flow in shoulder, ANS activity and breastfeeding posture in postpartum women. It was demonstrated for the first time that over-flexion of breastfeeding posture and stressful psychological state in postpartum might worse NSP through the modification of ANS and blood flow.
Several studies have reported that musculoskeletal pain such as NSP is related to psychological factors [6-9]. It was found in our study that “Disturbance of daily life due to NSP” might be associated with stressful psychological state, which resulted in predominant sympathetic nerve activity in ANS and the following decrease in surface skin temperature. Pichon et al. [10] reported that the depressive mood of undergraduate students in physical education was associated with changes in total rhythmic power of HRV. Sakuragi [11] demonstrated that both laughing and weeping in healthy female college students increased the LF/HF ratio of HRV and decreased the HF amplitude of heart rate variability(HRV). These studies suggest that the change of psychological state is directly related to ANS activity. Postpartum women are under psychologically stressful states, such as the anxiety about child-care, depression, feeling of chronic fatigue and so on. Thus the psychological state in postpartum women might be related with the worsening of NSP through the modification of ANS activity
We showed that the maximum and mean temperatures of the surface skin in “disturbance of daily life due to NSP ≧ 4.7” were significantly lower than those in “disturbance of daily life due to NSP <4.7”. Sakai et al. [12] measured the deep hemodynamics (tissue oxygen saturation : StO2, total hemoglobin concentration: total Hb) in the scapular region on the bilateral shoulders using a deep hemodynamics measurement system (PAS-IIIN, Biomedical science), and reported that patients with stiff shoulder showed a significant decrease in total Hb and StO2 in scapular region (midpoint C7 SP and acromion) compared with healthy volunteers. Taking them into account in our findings, decreased blood flow in the shoulder may result in the lower skin temperature of shoulder in postpartum women compared with severe NSP. Therefore it is important that the reduction of psychological stress and keeping balance of ANS activity will be provided in caring for prevention and mitigation of NSP in postpartum women. On the other hand, to assess the influence of breastfeeding on NSP in postpartum women, the angles in some body parts during breastfeeding posture were measured. Tilt angle of breastfeeding posture was associated with worse NSP after birth and “disturbance of daily life due to NSP”. Brink et al. [13] reported that an extreme cervical angle, and a combination of extreme cervical and thoracic angles among high school students using desktop computer were postural risk factors for the development of upper quadrant musculoskeletal pain. Szeto et al. [14] showed that there might be trends for increased head tilt and neck flexion postures in the symptomatic subjects, compared to the asymptomatic subjects of neck and shoulder pain based on video capture and two-dimensional motion analyses. As head tilt and flexion of the upper cervical, lower cervical and upper thoracic spinal segments increase, the magnitude of the sustained isometric muscle activity of paraspinal extensors increases in order to balance the increasing gravitational moments imposed. [15]. Muscles around the neck and the shoulder girdle of mothers support the baby’s head and arms during breastfeeding. Babies usually weigh more than 4 kg and have unstable neck between 1month and 4month at for birth. Besides, while breastfeeding, postpartum women keep holding their babies and strike tilt posture. Postures of postpartum women during breastfeeding tend to become unbalanced because of holding the not-held-head babies. As the baby’s weight increases rapidly, its load on shoulder muscles in postpartum women also increases. This finding indicated that breastfeeding posture might be one of the crucial factors in worsening NSP in postpartum women. It was speculated that the increased flexion posture during breastfeeding and the resulting increased muscle activity could lead to the worsening of NSP and musculoskeletal pain or discomfort.

Conclusion

This study was performed to elucidate the pathophysiology of NSP in relation to specific mental and physical states in postpartum women. Stressful psychological state may have caused worse NSP through the modification of ANS activity. Moreover, the breastfeeding posture is one of the important factors that worsen NSP in postpartum women. Especially, increase of head flexion seems to worsen NSP.It is essential that health professions teach postpartum women how to prevent or at least mitigate NSP. We should support postpartum women by suggesting comfortable postures during breastfeeding and relieving their stressful psychological state.

Acknowledgment

This work was supported by research grants from the Japan Academy of Midwifery 2012.

References
















Track Your Manuscript

Media Partners

Associations