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Foot baths are used in complementary and alternative therapy to improve the duration and quality of sleep and reduce tension, anxiety, fatigue, and confusion. They are also known to improve the frequency of labor contractions and to increase their duration in women; thus, they are commonly used by midwives in clinical settings in Japan. However, the physical and mental effects of foot baths during labor are unknown.
This study aims to assess the physical and mental effects of foot baths based on biomarker levels and self-administered questionnaires.
A single-arm pre-post test trial design is being used in this study, and the study is being conducted at a general hospital in Tochigi Prefecture, Japan. The target study population is women in the first stage of labor, the phase when the uterus starts to contract and when the cervix dilates to 10 cm, or those undergoing labor induction. Participants who meet the eligibility criteria are recruited, and written informed consent is obtained from them. They are asked to answer the questionnaire and to collect 1.5 mL of saliva in 2 microtubes each, before and after the intervention. The intervention is foot baths for 15-20 minutes using a foot bath device. Data on delivery, such as gestational age, gravidity, parity, diagnosis following the last vaginal examination, and presence or absence of membrane rupture, are retrieved from the medical records. The primary outcomes are salivary cortisol levels before and after the foot baths. The secondary outcomes are levels of relaxation and comfort, labor pain, body warmth, vital signs, and interval of labor pain before and after the foot baths, which are assessed using a numerical rating scale. A paired
Data collection started on April 1, 2022. As of October 2022, we had enrolled 10 participants. Because of the COVID-19 pandemic in Japan, it is difficult for medical personnel to freely interact with women in labor until the results of the COVID-19 polymerase chain reaction test are available in the research facility, complicating the recruitment process.
This is the first prospective study to assess the effects of foot baths using a biomarker during the first stage of labor. The findings on the effects of foot baths on women in labor will provide novel insights that may improve the outcomes of delivery. A randomized controlled trial to investigate the effects of foot baths to obtain robust evidence should be conducted in the future.
University Hospital Medical Information Network-Clinical Trial Registry UMIN000046539; https://tinyurl.com/2wwj7dns
DERR1-10.2196/39985
Foot baths are used for cleaning the feet and are useful in complementary and alternative therapy. Foot baths improve the duration and quality of sleep among postmenopausal and older adults [
Studies evaluating the effect of foot baths in the first stage of labor reported that they improve the frequency of labor contractions in women with slow labor [
The epidural labor rate has been increasing in Japan (4.6% in 2014, 5.5% in 2015, and 6.1% in 2016) [
This study aims to investigate the physical and mental effects of foot baths using a biomarker and self-administered questionnaire.
We are conducting a single-arm, pre-post test trial to evaluate the effectiveness of foot baths.
The study is being conducted at a general hospital in Tochigi Prefecture, Japan. The inclusion criteria are women in the first stage of labor or those undergoing labor induction. The first stage of labor is the phase when a pregnant woman’s uterus starts to contract and they feel persistent contractions and relaxation, and the cervix dilates to 10 cm. Women who cannot complete the questionnaire or cannot participate in the study because of labor pain or those who are judged to have difficulty participating in the study by midwives because of low literacy of Japanese or due to mental illnesses are excluded from recruitment.
This is a pre-post test trial; therefore, all participants are to receive the intervention. In this study, a foot bath is defined as the immersion of feet up to the ankle in hot water, set to a temperature that feels comfortable to the participants (38 °C to 42 °C) for 15-20 minutes (
Protocol of the study.
Data collection is being undertaken by research assistants, who are midwives working in the hospital and on duty, as assigned by the midwife in charge.
Data are collected using a self-administered questionnaire, laboratory assay for the biomarker, anthropometric measurements, and medical records. The self-administered questionnaire was adapted from those developed in previous studies that assessed the effects of foot baths [
The primary outcome of this study is salivary cortisol levels before and after the foot bath. The secondary outcomes are levels of labor pain, comfort and relaxation, and leg and body warmth, assessed using NRS scores, vital signs, and intervals of labor pain before and after the foot bath.
We asked some experienced midwives working at the hospital to assist in this study as research assistants. Before study initiation, instructions on data collection and intervention were provided and explained to the research assistants.
The research assistants recruit participants for the study and explain the purpose and contents of the study using an instruction sheet. After obtaining oral consent, written informed consent is obtained.
The research assistants provide the participants with the self-administered questionnaire along with a clipboard and pen. Participants are asked to complete the self-administered questionnaire. After completion, the midwives measure the participants’ vital signs (blood pressure, body temperature, pulse rate, and respiratory rate) and the interval and duration of labor pain.
They also request participants to provide 1.5 mL of saliva in 2 microtubes each. After saliva collection, the specimens are stored at −20 °C until analysis.
The research assistants provide foot baths to participants using a foot bath device (Hietori-kun Micon Premium, FB-C80, Koyo Co, Ltd, Gifu, Japan). The temperature of the water is set to 38 °C to 42 °C, as desired by the participants. AS mentioned, during the foot bath, the research assistants avoid applying pressure on acupoints. The participants are allowed to soak their feet in the bath quietly for 15-20 minutes.
After the foot bath, the research assistants provide the participants with a self-administered questionnaire with a clipboard and pen. After completing the questionnaire, they measure the vital signs (blood pressure, body temperature, pulse rate, and respiratory rate) and the interval and duration of labor pain.
After saliva collection, the specimens are stored at −20 °C until analysis. If the participants have difficulty providing saliva because of severe labor pain, only responding to the self-administered questionnaire and the measurement of the vital signs is allowed.
After recruitment, all salivary cortisol level measurements are conducted at Yanaihara Institute Inc, Shizuoka, Japan.
We will continue to recruit participants until the target sample size is attained, and we may consider adding another hospital as a study setting in case the recruitment does not progress favorably because of the COVID-19 pandemic. It is difficult for medical personnel to freely interact with women in labor until the results of the COVID-19 polymerase chain reaction test are available, complicating the recruitment process.
Data are double-checked during entry, and the data ranges are checked to ensure data quality. The collected data and questionnaires are stored in a locked cupboard.
According to a previous study that investigated differences in salivary cortisol levels before and after foot baths [
Neither patients nor the public are involved in the design, conduct, reporting, or dissemination of the study.
Categorical variables, such as marital status, education level, and occupation, will be presented as n (%), and continuous variables (salivary cortisol levels; NRS scores for labor pain, comfort, and relaxation; and vital signs, such as blood pressure, body temperature, pulse rate, and respiratory rate) will be presented as mean (SD) if normally distributed or as medians and interquartile ranges if nonnormally distributed. We will perform paired
All data will be analyzed using SPSS Statistics for Windows (version 28.0; IBM Corp). Two-tailed
In this study, foot bath devices with a constant temperature of hot water are used. When preparing hot water, the midwives check the temperature using a thermometer; however, the possibility of burns to the feet cannot be ruled out. Moreover, water spills on the floor may cause falls. In case of accidents, the midwives report to the obstetrician of the maternity ward and arrange for a doctor’s visit. The cost of medical treatment is to be covered by the participant’s health insurance coverage.
This study was approved by the Research Ethics Committee of the School of Nursing, Dokkyo Medical University, Japan (No. Nursing 03019) and the Research Ethics Committee of Kamitsuga General Hospital (No. 2021-008). The research assistants explain the purpose and contents of the study using an instruction sheet. Participation is voluntary. The possibility of harm and financial burden in case of accidents is explained to the participants. Written informed consent is obtained from all participants. Participants’ identifying information, such as their name, home address, and date of birth, is handled only by the hospital staff, and the information is never taken out of the research facility. All data will be analyzed anonymously, and participants’ other identifying information will be removed before analysis. The results of this study will be disseminated to scientific meetings and journals.
This study was registered in the University Hospital Medical Information Network-Clinical Trial Registry system (UMIN000046539) on January 17, 2022.
Data collection started on April 1, 2022. As of October 2022, we had enrolled 10 participants. Because of the COVID-19 pandemic in Japan, it is difficult for medical personnel to freely interact with women in labor until the results of the COVID-19 polymerase chain reaction test are available in the research facility, complicating the recruitment process. Moreover, the number of medical personnel who can engage in the research decreased in the research facility because some staff were infected by COVID-19; thus, recruitment is currently not progressing.
This is the first prospective study that will assess the effects of foot baths using a biomarker (salivary cortisol) in the first stage of labor. Though foot baths are commonly used by midwives in clinical settings in Japan and are expected to have psychological and labor-inducing effects, psychological effects using biomarkers have not been shown. Participant recruitment started on April 2022, but because of the COVID-19 pandemic in Japan, recruitment is currently not progressing.
Though several studies have reported the physical and mental effects of foot baths, they did not include women in labor as participants [
In Japan, the rate of epidural labor has been increasing recently [
The appropriateness of the methodology of this study should be discussed. In this study, the outcomes are measured using salivary cortisol and an NRS for the levels of labor pain and comfort, relaxation, and the degree of warmth of the legs and the entire body. Samples are collected during labor, and therefore, collecting saliva or answering the questionnaire may trigger pain or stress for some participants. However, scoring NRS is not time-consuming, and several studies have used visual analog scales to assess comfort or warmth [
Furthermore, we need to mention the potential physical harm from foot baths. Foot baths are one of the popular midwifery interventions in Japan due to their psychological and labor-inducing effects. Therefore, most midwives understand the necessary precautions, such as controlling the temperature of hot water and avoiding water spills on the floor. Nevertheless, in this study, we use foot bath devices to maintain the correct temperature of the hot water, although we cannot fully rule out the possibility of burns to the feet.
Moreover, this study uses a single-arm, pre-post test trial design; thus, the interpretation of the study findings requires some attention. With such a design, the results will only show within-individual differences. To obtain robust evidence on the effects of foot baths during labor, a randomized controlled trial should be conducted in the future.
The strength of this study is that this is the first study that assesses the effects of foot baths during the first stage of labor using a biomarker (salivary cortisol). Though several previous studies have reported the effects of foot baths, few have evaluated them using biomarkers; moreover, there are no studies using biomarkers among women in childbirth.
Nevertheless, this study has some limitations. First, the design of this study is a single-arm pre-post test trial; thus, it is difficult to judge the effects of foot baths. To obtain robust evidence of the effects of foot baths, randomized controlled trials should be conducted in the future. Second, because of the COVID-19 pandemic, participant recruitment has not progressed favorably. Therefore, adding another hospital as a study setting has to be considered.
This is the first prospective study that will assess the effects of foot baths using a biomarker (salivary cortisol) in the first stage of labor. Though participant recruitment has not progressed favorably because of the COVID-19 pandemic, if foot baths are shown to reduce stress in women in labor, they can be recommended for the nonmedical care of women in labor. A randomized controlled trial to investigate the effects of foot baths to obtain robust evidence should be conducted in the future.
numerical rating scale
This study has been funded by the School of Nursing, Dokkyo Medical University, Tochigi, Japan. The funding body did not have any role in the study design, data analysis, manuscript preparation, and submission.
Data sharing is not applicable to this article as no data sets have yet been generated or analyzed for the study.
NH, RI, KM, and AI were involved in the conception, design, and drafting of this manuscript. NH was involved in the writing and revision of the manuscript. All authors have read and approved the final version of the manuscript.
None declared.