Comparing the Effects of Progressive Muscle Relaxation and Guided Imagery on Sleep Quality in Primigravida Women Referring to Mashhad Health Care Centers -1393

Introduction

According to Maslow’s hierarchy of needs, sleep is one of the basic human needs (1). Sleep disorders are more common in women than men due to hormonal changes during menstrual cycle, pregnancy, and menopause (2).

Pregnancy is one of the causes of sleep disorders (3). Decreased sleep quality is one of the common complaints during pregnancy (4), mostly occurring in the third trimester of pregnancy as the mother approaches the end of pregnancy. In fact, the incidence of sleep disorders has been reported around 75% in the third trimester (5). Poor sleep quality could be related to preterm labor, low birth weight, blood pressure disorders, glucose tolerance disorders, and depression during and after pregnancy (6-10).

The most common therapeutic methods for sleep disorders are pharmaceutical treatments in which by the suppression of the central nervous system, anxiety and stress levels decrease and the patient becomes hypnotic and relaxed (11). However, pharmaceutical methods are contraindicated during pregnancy due to some potential risks for the fetus and their impacts on fetal growth and development (12). Therefore, alternative non-pharmaceutical methods with no side-effects should substitute pharmaceutical methods for the treatment of sleep disorders.

Behavioral therapy is one of non-pharmaceutical methods for sleep problems. Relaxation, which relieves external stressors, has been widely applied in recent years and is considered a simple, feasible and useful behavioral approach (13-15). There are various relaxation techniques such as progressive muscle relaxation, guided imagery, massage, hypnotism, yoga, music therapy, and breathing techniques (7). Progressive muscle relaxation is a widely-applied method, which has been shown to be effective in decreasing physical and cognitive stress and improving self-confidence (14, 16).

In a study by Watanabe et al. (2006), guided imagery could decrease stress and increase the emotional stability of the participants (17). Different relaxation techniques have different impacts on various biological and emotional stressors. However, little research has been performed to determine which method is most effective (13).

Pregnancy is a stressful event for women. Stress rate increases in the third trimester of pregnancy and near the labor time. In fact, stress is an indispensable cause of poor sleep quality (13). Morine et al. (2006) introduced methods of improving sleep quality such as progressive muscle relaxation to decrease somatic stress and guided imagery, as well as meditation, for removing distractive thoughts during sleep (18).

Malekzadegan et al. (2010) showed the effectiveness of progressive muscle relaxation in improving sleep disorders during the third trimester of pregnancy (19). The main principle of progressive muscle relaxation is the individual’s sitting position. In other words, the head should be placed along the trunk, the vertebral column should be straight, and the curves should be filled.

During pregnancy, considering the enlargement of the abdomen, the mentioned sitting position without displacement is probably not easy for women, and the supine position could press the uterine vessels (12, 15). It seems that guided imagery is of priority since it requires no specific sitting position and could be simply performed in a limited amount of time (13, 14).

Guided imagery is a cognitive-behavioral technique in which the individual is guided in imagining a series of experiences for controlling stress and balancing negative thoughts (20). In a study by Krakow et al. (2001), mental imagery was considered a well-tolerated method by patients with post-traumatic stress disorders, suffering from nightmares (21). Also, Schaffer et al. (2013) showed a significant correlation between the sleep quality of mothers with premature neonates and mental distress; as the results showed, sleep quality improved by guided imagery (22).

Kwekkeboom et al. (2008) did not report a significant association between pain reduction and progressive muscle relaxation or guided imagery in cancer patients (23). However, Urech et al. (2010), who compared the effects of progressive muscle relaxation and guided imagery on the mental, cardiovascular, and endocrine status of pregnant women, showed that guided imagery resulted in lower heart rate and more relaxation, compared to the other technique (24).

Regarding the high incidence of sleep disorders during pregnancy and their adverse effects on maternal and fetal health, it is impossible to apply pharmaceutical approaches during pregnancy. Therefore, it is necessary to find safe methods for improving pregnant women’s sleep quality. The present study aimed to compare the effects of progressive muscle relaxation and guided imagery on the sleep quality of pregnant women in Mashhad in 2014.

Materials and Methods

In the present three-group clinical trial, health care center No. 1 was selected among five health care centers of Mashhad via random sampling. Based on the number of clients, two health care centers, affiliated to health center No. 1, were selected via non-probable sampling. Subjects who met the inclusion criteria were introduced to the study. Data were collected using a demographic form, an obstetric checklist, and Pittsburgh Sleep Quality Index (PSQI).

PSQI is an international instrument for assessing sleep quality. This scale evaluates a person’s attitude towards sleeping quality in the last four weeks. It includes 9 questions in 7 components of subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep disturbance, use of sleep medication, and daytime dysfunction. The items are scored using a Likert scale, ranging from 0 to 3 (3= the highest negative score). The total score is calculated by summing the scores of components, ranging from 0 to 21; scores ≥ 5 indicate poor sleep quality (25).

The reliability of PSQI was calculated by Cronbach’s alpha (α=0.73) (26). In Iran, Hossein Abadi et al. (2008) has confirmed the validity (r=0.88) and reliability of PSQI (r=0.84), using test-retest (27). This instrument is applicable for evaluating sleep quality during pregnancy (26) and its reliability in present study was calculated to be 0.77.

The inclusion criteria were as follows: 1) primigravidity; 2) gestational age of 29-32 weeks; 3) singleton pregnancy; 4) low-risk pregnancy; 5) no history of infertility; 6) no prior history of mental or physical diseases; 7) no history of drug addiction; 8) literacy (minimum of junior high education); 9) no stressful events within the last six months; 10) Pittsburgh score ≥ 5 (patients with sleep disorders); 11) no treatments for sleep disorders before pregnancy, 12) no night shifts during the study period; and 13) no relaxation methods during pregnancy.

The exclusion criteria were as follows: 1) unwillingness to continue participation in the study; 2) not performing relaxation exercises once a week; and 3) obstetric problems or stressful events during the study period.

In order to calculate the sample size, the formula used in previous two-group studies, which evaluated sleep quality, was applied and post-intervention values reported in these studies were used (19, 21). In order to determine the sample size in the guided imagery group, 8.21±3.99 and 12.76±4.63 were considered for the intervention and control groups, respectively. In the progressive muscle relaxation group, 5.08±1.86 and 8.31±4.24 were considered for the intervention and control groups, respectively. Therefore, the sample size was calculated to be 100, considering CI=95% and power=90% (10% dropout).

Informed consents were obtained from the participants, and the subjects were randomly assigned to three groups of progressive muscle relaxation (n=33), guided imagery (n=33), and control (n=34) by drawing lots. The names of the three groups were written on three pieces of paper: A) progressive muscle relaxation, B) guided imagery, and C) control; then, a third party (a midwife at the center) selected one piece by chance.

In order to prevent data contamination (i.e., exchange of information between the participants), each 10-day period was allocated to a particular intervention. Sampling continued to the end of the study. Training sessions were held for groups of 3-5 participants during two weeks (45-60 minutes per session) for two intervention groups. The sessions started with an introduction to the study, sleep hygiene, and training of relaxation techniques to each group.

Progressive muscle relaxation was instructed based on Jacobson’s method by relaxing and contracting 8 muscle groups (modified for abdominal muscles in pregnancy). Guided imagery was instructed by encouraging positive feelings of peacefulness and safety and guiding individuals to imagine beautiful scenes; educational films were also presented by the researcher. At the end of sessions, a booklet and a CD about the presented content and relaxation techniques were given to each group for practicing at home.

The subjects were asked to do the exercises twice a day (once in the morning and once before sleeping at night) for a period of 4 weeks and mark the exercise checklist. During the second session, the content of the first session was repeated and the participants were asked to do the exercises. The researcher assessed the checklists to answer the subjects’ questions and be assured about the accuracy of techniques.

 If the exercises were accurately performed and the checklist was completed in the first and second sessions, the one-week interval between the first and second sessions was also considered in the four-week period. However, if the exercises were not performed correctly and the subjects were willing to continue the study, the researcher repeated the instructions.

The researcher contacted the participants at the end of the first, second, third, and fourth weeks and emphasized the importance of doing regular exercises. After four weeks, sleep quality was assessed using PSQI in all groups, and the pre- and post-intervention results were compared. If the participants experienced other sleep disorders (such as apnea, nightmares, narcolepsy, and restlessness leg syndrome, or severe insomnia), they were referred to psychiatrists.

In order to observe ethical considerations, after the recompletion of PSQI, the instructional booklet was given to the control group, as well. In total, two participants were excluded from the study due to migration, two due to unwillingness to continue the study, and one due to unavailability; finally, the data of 95 participants were analyzed.

Descriptive and analytical tests were performed, using SPSS version 11.5. If the data were normally distributed, parametric ANOVA test and paired t-test were applied; if not, Kruskal-Wallis and Wilcoxon tests were performed. If ANOVA and Kruskal-Wallis tests were significant, post-hoc tests were applied for the comparison between the two groups.

Results

The participants were not significantly different in terms of age, body mass index (BMI), gestational age, daily sleep duration, or daily exercise time (P>0.05) (Table 1). They were also similar in terms of sleep distractors such as light (P=0.98) and noise (P=0.92). One-way ANOVA showed no significant difference in the mean score of sleep quality before the intervention between the three groups (P=0.17); however, the difference was significant after the intervention (P<0.001).

In order to compare the two groups separately, Tukey test was performed. The results indicated a significant difference between the two intervention groups (P=0.015). Paired t-test also showed a significant difference between the pre- and post-intervention periods in these groups (P<0.001) (Table 2). There was a significant difference in the score of different PSQI components before and after the intervention, as well (P<0.001) (Table 3). Also, there was a significant difference in the components of sleep quality between the control and intervention groups (P<0.001).