*Department of Obstetrics and Gynecology, Thammasat University, Pathum Thani 12120, Thailand. , **Chulabhorn International College of Medicine, Thammasat University, Pathum Thani 12120, Thailand.
ABSTRACT
INTRODUCTION
Labor pain is one of the most painful experiences in a woman’s life. It results from contraction of the uterus, dilation of the cervix, and dilation of the adjacent pelvic organs. This pain has significant physiological effects
on the health of the mother and fetus.1 Therefore, its minimization in the intrapartum period is considered crucial. Conventional methods can reduce pain during labor2 but also have disadvantages, such as decreased consciousness during labor, respiratory distress in the
Corresponding author: Pichita Prasongvej E-mail: pichita.pra@gmail.com
Received 27 June 2023 Revised 10 August 2023 Accepted 13 August 2023 ORCID ID:http://orcid.org/0000-0002-0485-4367 https://doi.org/10.33192/smj.v75i10.263860
All material is licensed under terms of the Creative Commons Attribution 4.0 International (CC-BY-NC-ND 4.0) license unless otherwise stated.
newborn3, slowing of the fetal heart rate1, maternal respiratory suppression, nausea, vomiting, dizziness, and drowsiness.1,4 For these reasons, non-pharmacological methods such as music therapy, yoga, relaxation, and other methods are becoming more popular worldwide.5 Several studies have shown that music therapy can reduce anxiety, stress, and pain in pregnant women5-10 by stimulating the brain to produce dopamine and endogenous opioids.8 In addition, music therapy has been found to improve heart rate variability in pregnant women.9 Other studies have shown that geranium, frankincense, lavender, jasmine, and rose essential oils can relieve anxiety and labor pain.11,12 Ginger essential oil (GEO; Zingiber officinale Roscoe) is an essential oil extracted from the ginger plant and abundant in Southeast Asia. It is currently available worldwide and is used to relieve pain in various organs through various mechanisms.13 However, studies on labor pain after inhalation have not yet been conducted. These two alternative therapies are simple, inexpensive, and have no serious side effects. Therefore, we aim to investigate the efficacy of music therapy and GEO aromatherapy for pain relief in the
first stage of labor.
MATERIALS AND METHODS
This randomized controlled trial was conducted among pregnant women admitted to the delivery room of Thammasat University Hospital from May 2022 to
March 2023. A flowchart of the study according to the Consolidated Standards of Reporting Trials (CONSORT) is shown in Fig 1. The inclusion criteria were nulliparous, pregnant women aged 15 to 45 years old, singleton pregnancy, gestational age of ≥ 37 weeks, initial cervical dilation of 3 cm, use of oxytocin for labor augmentation, and ability to understand and communicate Thai language. Exclusion criteria were women who had an indication for cesarean section since admission, did not have a cephalic presentation, and had schizophrenia, anosmia, deafness, or chronic diseases that can exacerbate back pain or Covid-19 infection. Women who experienced adverse effects such as nausea and dizziness after inhaling GEO disliked the smell of GEO after using it for more than 10 minutes, experienced headaches or pain in their ears when listening to music for more than an hour, disliked the music, or were uncomfortable using headphones, or removed headphones for more than an hour were excluded from the study. Women who received opioid or regional anesthesia during delivery and women who wanted to end their participation in the study were also later excluded from the study.
After admission to the delivery room, research assistants presented and explained the research objectives to potential candidates who met the inclusion criteria. If they decided to participate in the study, their consent was obtained. Baseline data and clinical symptoms were recorded on a data collection form. Participants were
Fig 1. The CONSORT flow diagram of study participants
randomly assigned to three experimental groups: the control group, the music group, and the GEO aromatherapy group. The consecutively numbered assignments were sealed in opaque envelopes. Each group was placed in a different room. The control group received routine treatment, while the music group listened to a collection of music entitled “Musical Journey through Pregnancy”10 through headphones, consisting of 8 songs that were uplifting, gentle, and natural sounds. The aromatherapy group inhaled the GEO reed diffuser placed next to the bed, and participants in all groups were in different rooms. All three groups received interventions and were assessed for pain every 2 hours using a visual analog scale (VAS) until the end of the first stage of labor or cesarean section was indicated. Satisfaction was assessed after the end of labor. The pain scale was divided into mild (pain score 0-3), moderate (pain score 4-6), and severe (pain score 7-10) pain groups for further and more precise information.
The sample size was calculated using the formula with two independent groups, and the mean values of
3.82 and 4.39 were used from a previous study.14 With an alpha-type error rate of 1% (two-sided) and statistical power of 80% (one-sided), the estimated sample size per group was 93. With an expected sample loss of 5%, the
final size was adjusted to 100 cases per group, resulting in a total of 300 participants in the study.
Descriptive statistics were reported as mean, percentage, frequency, and standard deviation. Statistical Package for the Social Sciences version 23 (SPSS Inc., Chicago, IL, USA) was used for data analysis. One-way analysis ANOVA was performed, and a p-value < 0.05 was considered statistically significant.
RESULTS
A total of 300 nulliparous pregnant women were randomized equally to the control, music, and aromatherapy groups, with no participant withdrawal. The average age was 27.7 years old. The gestational age of each group was approximately 38 weeks. About half (145/300) of participants had a normal BMI. Almost all participants had no underlying diseases. There were no significant differences in participants’ characteristics between groups, as shown in Table 1.
Our study showed no differences in baseline VAS scores among the three groups. The mean VAS at cervical dilation of 4-5 cm were 6.1, 1.9, 2.6, and at the dilation of
6-7 cm, were 8.0, 2.8, and 3.6 for the control, music, and aromatherapy groups, respectively. The VAS score for cervical dilatations of 4-5 cm and 6-7 cm was significantly lower in both intervention groups than in the control group (p < 0.001), and the VAS score in the music group
TABLE 1. Demographic of the participants (100 case each).
Demographic | Control | Music | Aroma | P-value* |
Age (years), mean ± SD | 28.0±4.7 | 28.0±5.6 | 27.07±4.9 | 0.303 |
Gestational age (weeks), mean ± SD | 38.5±1.1 | 38.1±3.2 | 38.1±1.0 | 0.344 |
BMI, n (%) Underweight | 28 (28) | 29 (29) | 30 (30) | 0.803 |
Normal | 45 (45) | 49 (49) | 51 (51) | |
Overweight | 19 (19) | 16 (16) | 16 (16) | |
Obese | 8 (8) | 6 (6) | 3 (3) | |
Gestational weight gain (kg), mean ± SD | 13.1±4.4 | 12.9±4.9 | 12.0±5.1 | 0.254 |
Underlying disease, n (%) | 2 (2) | 1 (1) | 4 (4) | 0.359 |
Pregnancy complication, n (%) GDM | 11 (11) | 10 (10) | 9 (9) | 0.409 |
PIH | 7 (7) | 2 (2) | 3 (3) | |
Others | 3 (3) | 6 (6) | 4 (4) |
*; Analysis of variance p-value <0.05 indicates statistically significant
was significantly lower than in the aromatherapy group (p < 0.001).
In addition, the VAS score was further subdivided into severity levels. With cervical dilation of 4-5 cm, all participants in both intervention groups had mild pain. In contrast, most participants in the control group had moderate pain. At cervical dilation of 6-7 cm, all participants in the music group had mild pain; three- fourths of participants in the aromatherapy group also had mild pain, while most participants in the control group had severe pain, as shown in Table 2.
In both intervention groups, the first and second stages of labor were significantly shorter than in the control group. There were no differences in the rate of cesarean deliveries among the three groups, the most common indication being (15, 16, and 11 cases in the control, music, and aromatherapy groups, respectively, in that order). Another indication that led to cesarean delivery in the control group was abnormal fetal heart rate. Moreover, the estimated blood loss (EBL) for vaginal delivery was significantly lower in both intervention groups than in the control group (p < 0.001). However, no difference was found for cesarean delivery (p = 0.305). The mean birth weight was 3.0-3.1 kg in all groups. Almost all
neonates in all groups had standard Apgar scores in the first and fifth minutes of life, except for one case in the control group with an Apgar score of 5.6 in the first and fifth minutes of life, subsequently. All pregnant women in both intervention groups reported high satisfaction with a score of 7-10 out of a total of 10 points, while about four-fifths of participants in the control group were only moderately satisfied with a score of 4-6 out of a total of 10 points.
DISCUSSION
The management of labor pain is one of the significant issues in obstetrics, for which various methods of relief are being explored. Previous studies showed that noninvasive complementary and adjunctive strategies, namely music therapy and aromatherapy, significantly reduce initial labor pain7,15,19 (and other clinically relevant outcomes.10,15 In addition, many studies have found that both interventions can reduce anxiety in stressful situations.5,6,9,11,16,20 Currently, no study uses GEO inhalation and compares GEO aromatherapy with music therapy for pain relief in the first stage of labor. Therefore, we propose these two therapies for nulliparous pregnant women to treat labor pain in the first stage of labor.
TABLE 2. Pain score and severity score of the participants during various cervical dilatation.
Cervical dilate (cm) | Control | Music | Aroma | P-value* |
3, mean ± SD | 1.3±0.5 | 1.4±0.5 | 1.4±0.5 | 0.338 |
4-5, mean ± SD | 6.1±0.7§ | 1.9±0.7¶ | 2.6±0.4 | <0.001 |
Pain severity score, n (%) Mild Moderate Severe | 0 79 (80.6) 19 (19.4) | 99 (100) 0 (0) 0 (0) | 92 (100) 0 (0) 0 (0) | <0.001 |
6-7, mean ± SD | 8.0±0.7§ | 2.8±0.4¶ | 3.6±0.3 | <0.001 |
Pain severity score, n (%) Mild Moderate Severe | 0 (0) 3 (3.3) 87 (96.7) | 95 (100) 0 (0) 0 (0) | 62 (72.9) 23 (27.1) 0 (0) | <0.001 |
8-10, mean ± SD | 9.1±0.3 | 9.0±0.8 | 9.0±0.7 | 0.859 |
Pain severity score, n (%) Mild | 0 (0) | 0 (0) | 0 (0) | |
Moderate | 0 (0) | 0 (0) | 0 (0) | |
Severe | 91 (100) | 95 (100) | 96 (100) |
*; Analysis of variance p-value <0.05 indicates statistically significant, §; Significant difference from the other 2 group, ¶; Significant difference from aroma group, Pain score 0-3; mild, 4-6; moderate, 7-10; severe pain
TABLE 3. Obstetrics data of the participants (100 case each).
Control | Music | Aroma | P-value* | |
Time labor (min)† 1st stage 2nd stage | 513.0±178.7§ 23.1±14.7§ | 381.8±145.8 15.0±10.4 | 383.5±160.8 15.3±10.1 | <0.001 <0.001 |
C/D‡ | 19(19) | 16(16) | 11(11) | 0.284 |
V/DEBL (ml)† | 347.0±212.2§ | 144.1±100.7 | 150.0±85.3 | <0.001 |
BW (kg)† | 3.1±0.4 | 3.1±0.4 | 3.0 ±0.4 | 0.095 |
Apgar ≥7‡ 1 min 5 min | 99 (99) 99 (99) | 100 (100) 100 (100) | 100 (100) 100 (100) | 0.367 |
Satisfaction‡ Moderate (4-6) | 81 (81) | 0 (0) | 0 (0) | <0.001 |
Excellent (7-10) | 19 (19) | 100 (100) | 100 (100) |
*; Analysis of variance p-value <0.05 indicates statistically significant, †; mean± standard deviation, §; Significant difference from the other 2 group, ‡; n (%)
In our study, participants were distributed among the research groups, and there were no significant differences in demographic characteristics. Most participants in the three groups had no underlying diseases, and there were no differences in cervical dilation, baseline pain scores, or augmentation rates.
Our study showed that participants in both intervention groups had significantly less labor pain than the control group when cervical dilation was 4-7 cm. Based on these results, we can assume that both music and aromatherapy are effective in reducing pain in the early active phase of the first stage of labor, which is consistent with previous studies in both the music7,17,18 and aromatherapy groups14,16,19 In addition, our study found that music therapy was more effective than GEO aromatherapy in reducing labor pain in the early active phase. The mechanism for pain relief in both interventions is unclear. However, music and aromatherapy may stimulate brain substances that serve as natural analgesics. However, in the late active phase of labor (cervical dilation of 8-10 cm), no significant difference in the severity of labor pain was observed among the three groups in our study. A lower focus on both interventions can explain this, as pain is more intense in the late active phase of labor.
Furthermore, we could hypothesize that music therapy is beneficial in shortening the duration of the first and second stages of labor, which is consistent with
Gonzalez’s study.10 Although this result contradicts a previous study by Guo15, which found that music can prolong the first stage of labor, these different results may be explained by differences in the type of music and the duration of music listening.
Additionally, GEO aromatherapy has significantly reduced the duration of the first and second stages of labor. This finding contrasts the results reported by Tanvisut14 and Yazdkhasti.19 It could be due to differences in the type of aromatherapy, the duration during which the participants were exposed to the fragrances, and the diffuser used.
Our study also showed that both intervention groups had a statistically significant reduction in EBL during vaginal delivery, consistent with the results reported by Guo.15 However, the mechanisms responsible for these results remained unexplained. Both intervention groups showed higher satisfaction levels than the control group, which may be due to the calming effect of these interventions, which helped to reduce stress during the waiting period.
Our study is the first to report the effectiveness of music therapy in reducing the time of the second stage of labor. In addition, our research reports for the first time that the scent of GEO can effectively reduce labor pain during the early active phase of the first stage of labor, the duration of labor, and EBL for vaginal birth.
Our results could be a milestone for future studies. At the same time, we are aware of the study’s limitations, such as the lack of blindness to interventions and the fact that it is a single-center design.
CONCLUSION
This study showed that music and GEO aromatherapy effectively reduced labor pain in the early active phase of the first stage of labor, with music therapy being an effective therapy. In addition, music and GEO aromatherapy reduced the duration of the first and second phases of labor, estimated blood loss during vaginal delivery, and had higher satisfaction levels among participants in both intervention groups. This study recommends both therapies as a cost-effective and complementary approach for treating initial labor pain in the delivery room.
ACKNOWLEDGMENTS
This study was supported by the Research Fund of the Faculty of Medicine, Thammasat University. The authors would like to thank Assoc. Prof. Dr. Dittakarn Boriboonhirunsarn for his kind help in preparing the manuscript.
Authors declare no conflict of interest for this article.
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