Abstract

The article aims to verify the influence of MNFs on the duration of the birth process. A systematic review was carried out in the MEDLINE, Web of Science and LILACS databases, through a combination of terms that cover the topic addressed, from 1996 to 2021/April. The Excel spreadsheet was used to collect data to extract information regarding each selected article, in turn, data analysis included the evaluation and classification of quality, reliability and risk of bias, thus, the following tools were used: Cochrane RoB 2, Checklist and Newcastle-Ottawa Scale. Warm bath, walking, exercises with a birthing ball, breathing techniques, supine position, acupuncture, acupressure and water birth reduced labor time. While spontaneous pushing, massage and immersion baths prolonged labor. Non-pharmacological methods capable of reducing the duration of labor were hot/warm shower, walking, birth ball exercises, breathing techniques, maternal mobility, dorsal position, acupuncture, acupressure and water birth, as well. associated applied techniques such as hot/warm bath, ball exercises and lumbosacral massage, as well as immersion bath, ball exercises, aromatherapy, vertical postures and maternal mobility with alternating vertical postures, shortened the birth time.

Key words:
Methods; Parturition; Humanizing delivery; Time

Resumo

O objetivo do artigo é verificar a influência dos MNFs na duração do processo de parto. Realizou-se uma revisão sistemática nas bases de dados MEDLINE, Web of Science e LILACS, por meio da combinação de termos que contemple a temática abordada, no período de 1996 a 2021/abril. Utilizou-se para coleta de dados a planilha Excel para extração de informações referentes a cada artigo selecionado, por sua vez, a análise dos dados compreendeu a avaliação e classificação da qualidade, confiabilidade e risco de viés, assim, utilizou-se como ferramentas: Cochrane RoB 2, Checklist e Escala de Newcastle-Ottawa. Reduziram o tempo de trabalho de parto banho morno, caminhada, exercícios com bola de parto, técnicas respiratórias, decúbito dorsal, acupuntura, acupressão e parto na água. Enquanto empurrões espontâneos, massagem e banho de imersão prolongaram o trabalho de parto. Os métodos não farmacológicos capazes de reduzir a duração do trabalho de parto foram banho de chuveiro quente/morno, caminhada, exercícios com bola de parto, técnicas de respiração, mobilidade materna, posição dorsal, acupuntura, acupressão e parto na água, também encurtaram o tempo de parto técnicas aplicadas associadas como banho quente/morno, exercícios com bola e massagem lombossacral, assim como banho de imersão, exercícios com bola, aromaterapia, posturas verticais e mobilidade materna com posturas verticais alternadas.

Palavras-chave:
Métodos; Parto; Parto humanizado; Tempo

Introduction

Labor involves movements of the fetus that guide it along the birth canal, promoted by contractions of the uterus¹1 Montenegro CAB, Rezende Filho J. Rezende obstetrícia. 13ª ed. Rio de Janeiro: Grupo GEN; 2016.. In this process, the first and longest stage is dilation, lasting 10-12 hours in primiparous women and 6-8 hours in multiparas¹1 Montenegro CAB, Rezende Filho J. Rezende obstetrícia. 13ª ed. Rio de Janeiro: Grupo GEN; 2016.

2 Brasil. Ministério da Saúde (MS). Secretaria de Políticas da Saúde. Parto, aborto e puerpério: assistência humanizada à mulher. Brasília: MS, FEBRASGO, ABENFO; 2001.^-33 Porto AMF, Amorim MMR, Souza ASR. Assistência ao primeiro período do trabalho de parto baseada em evidências. Femina 2010; 38(10):527-537.. The second, expulsion begins at full dilation and can be divided into passive and active gain. The active phase lasts up to 3 hours in primiparous women and up to 2 hours in multiparous women⁴4 Brasil. Ministério da Saúde (MS). Secretaria de Ciência, Tecnologia e Insumos Estratégicos. Departamento de Gestão e Incorporação de Tecnologias em Saúde. Diretrizes nacionais de assistência ao parto normal: versão resumida. Brasília: MS; 2017..

As it is possible that the stages of labor are long and exhausting, it is important, in addition to the humanized assistance recommended in the guidance for labor and birth, to include non-pharmacological methods (NPMs) that can reduce the duration of labor and make the process more comfortable for fetus and mother²2 Brasil. Ministério da Saúde (MS). Secretaria de Políticas da Saúde. Parto, aborto e puerpério: assistência humanizada à mulher. Brasília: MS, FEBRASGO, ABENFO; 2001.^,33 Porto AMF, Amorim MMR, Souza ASR. Assistência ao primeiro período do trabalho de parto baseada em evidências. Femina 2010; 38(10):527-537..

Thus, NPMs have been encouraged for over 25 years. It can confer benefits through relaxation promoted by pain relief and also by promoting greater effectiveness of uterine contractions⁵5 Mamede FV, Almeida AM, Clapis MJ. Movimentação/deambulação no trabalho de parto: uma revisão. Acta Sci Health Sci 2004; 26(2):295-302.^,66 World Health Organization (WHO). Care in normal birth: a pratical guide. Maternal and Newborn Health/Safe Motherhood Unit. Family and Reproductive Health. Geneva: WHO; 1996.. More active parturients, such as women who walk around during labor tend to have a shorter labor⁷7 Bio E, Bittar RE, Zugaib M. Influência da mobilidade materna na duração da fase ativa do trabalho de parto. Rev Bras Ginecol Obstetr 2006; 28(11):671-679.^,88 Gallo RBS, Santana LS, Marcolin AC, Duarte G, Quintana SM. Sequential application of non-pharmacological interventions reduces the severity of labour pain, delays use of pharmacological analgesia, and improves some obstetric outcomes: a randomised trial. J Physiother 2018; 64(1):33-40., as well as those who change position along with the movements, practice birth ball exercises and receive massages⁷7 Bio E, Bittar RE, Zugaib M. Influência da mobilidade materna na duração da fase ativa do trabalho de parto. Rev Bras Ginecol Obstetr 2006; 28(11):671-679.. They are also more satisfied with the duration of the first and second stages of labor⁸8 Gallo RBS, Santana LS, Marcolin AC, Duarte G, Quintana SM. Sequential application of non-pharmacological interventions reduces the severity of labour pain, delays use of pharmacological analgesia, and improves some obstetric outcomes: a randomised trial. J Physiother 2018; 64(1):33-40.. Acupressure, Chinese medicine stimuli, also help to reduce the duration of labor⁹9 Makvandi S, Mirzaiinajmabadi K, Sadeghi R, Mahdavian M, Karimi L. Meta-analysis of the effect of acupressure on duration of labor and mode of delivery. Int J Gynecol Obstet 2016; 135(1):5-10.. However, the effectiveness and effects of MNPs are still unclear, so it is still unclear which MNP is most effective in reducing the duration of labor and what is the best frequency and stage of labor that should be applied¹⁰10 Jones L, Othman M, Dowswell T, Alfirevic Z, Gates S, Newburn M, Jordan S, Lavender T, Neilson JP. Pain management for women in labour: an overview of systematic reviews. Cochrane Database Syst Rev 2012; 2012(3):CD009234..

In this context, seeking evidence on the effects of NPM on the duration of labor is important to help improve care for parturients. The aim of the present study was to verify the influence of NPMs on the duration of the labor process.

Method

A systematic review was performed to map the effects of NPMs used in the labor process on the duration of labor and delivery. This approach was chosen to provide a broader capture of the available evidence on the topic, allowing deeper insights to be gained.

To determine the research question and search for evidence, the PICO strategy was used to facilitate the planning and execution of the study.

A bibliographic search was carried out between April 6 and 13, 2021. The selected databases for the search included MEDLINE (Medical Literature Analysis and Retrieval System Online - accessed via PubMed), Web of Science, and LILACS (Literatura Latino-Americana e do Caribe em Ciências da Saúde - accessed via the Regional da Biblioteca Virtual em Saúde - BVS portal). The search strings employed were built using terms registered in MeSH (Medical Subject Headings) - controlled vocabulary for indexing articles in the scientific literature - combined according to the search strategy chosen.

The inclusion criteria were studies of any design type, published between 1995 and April 2021, and in any language. Filters were applied to guide the search of studies for the review, according to the specific options available for each database or search site.

Thus, for PubMed, the search was carried out on April 6, with the initial retrieval of 2,089 publications, reduced to 1,431 records after applying filters by year of publication (1995-2021), human and female. For the Web of Science database, the search took place on April 13, identifying 1,205 studies, of which 1,118 were selected for the initial analysis after applying the year of publication filter (1995-2021). The search in the BVS was carried out on April 13, initially with 5,428 records, this total was reduced to 153 publications after restricting the results to studies carried out in the LILACS database, involving humans and women, and for the publication period (1995-2021). Therefore, 2,700 publications were included in the first stage of the review.

Searches retrieved studies published from 1996 to the date of the search (April 6-13, 2021). The justification for the chosen period was based on the fact that, in 1985, a meeting of specialists from all over the world was held by the World Health Organization (WHO), during which a series of practical recommendations to be used for the care in normal birth conditions were made⁶6 World Health Organization (WHO). Care in normal birth: a pratical guide. Maternal and Newborn Health/Safe Motherhood Unit. Family and Reproductive Health. Geneva: WHO; 1996.. However, despite encouragement to use evidence-based evidence, many of these practices have not been implemented. Only in 1996 did the WHO publish a guide for safe motherhood, establishing what is and what is not indicated during the care of mothers and babies in the normal delivery process⁶6 World Health Organization (WHO). Care in normal birth: a pratical guide. Maternal and Newborn Health/Safe Motherhood Unit. Family and Reproductive Health. Geneva: WHO; 1996..

The duration of labor, or its phases, is an outcome that deserves study, although it is not the main outcome. Interventions evaluated vary, as several different NFMs are used during labor that can alter the duration of this process. Regarding the study population, although parturients were the target population, studies with health professionals who apply methods that can influence the duration of labor were also included, as defined in the PICO strategy.

The stages of selection and application of the eligibility criteria were carried out by two researchers, aiming to respond to the study proposal. Reference manager was not used in the execution of this research.

Criteria for exclusion were publications studying a specific population (e.g. individuals presenting disease, such as multiple sclerosis, cancer, HIV, obesity; specific obstetric conditions such as pelvic or premature baby; women given analgesics or an amniotomy), studies not addressing NPM associated with duration of labor and/or one of its stages, that failed to specify the strategies used, or analyzed the third stage of labor only (after birth). Literature reviews were also excluded from the present work, reserving these for discussion. The low methodological quality did not motivate exclusion of publications.

Seven studies were classified as unavailable, i.e. sought by accessing the CAPES Journals Site, Research Gate and Google Scholar, and by contacting the respective authors via e-mail, to no avail.

The first step of selecting the retrieved publications included reading the title and abstracts of the identified studies, applying the eligibility criteria. In the second stage, the full text of the studies selected in a new screening was read. This step produced the final list of studies for inclusion in the analysis.

After that, the studies were all read in depth, and the data extracted in forms (Google Forms) and Excel spreadsheet (Microsoft Office).

The data extraction form included fields that collect study title, author(s), year of publication, journal, country, study location, study type, study objective, sample type, sample size, inclusion criteria, exclusion criteria, study variables, inclusion of the control group, measurement instruments, study duration, interventions, results found, statistical treatment, coherence of conclusions, authors’ recommendations and classification of the quality level.

Publications were assessed and classified for quality, reliability and risk of bias using appropriate instruments for each type of study design.

The revised Cochrane risk-of-bias tool for randomized trials (RoB 2) was used for experimental studies¹¹11 Higgins JPT, Savovic J, Page MJ, Sterne JAC. Revised Cochrane risk-of-bias tool for randomized trials (RoB 2): short version (CRIBSHEET) [Internet]. 2019 [cited 2023 jul 8]. Available from: https://methods.cochrane.org/bias/resources/rob-2-revised-cochrane-risk-bias-tool-randomized-trials.
https://methods.cochrane.org/bias/resour... , comprises 5 domains of bias (randomization, intervention, missing data, measurement, and results reporting) and expresses a result categorizing the study as Low risk of bias (good evidence quality), Some concerns, or High risk of bias (low evidence quality). The Checklist for quasi-experimental studies (non-randomized experimental studies) of the Joanna Briggs Institute¹²12 Tufanaru C, Munn Z, Aromataris E, Campbell J, Hopp L. Systematic reviews of effectiveness. In: Aromataris E, Lockwood C, Porritt K, Pilla B, Jordan Z, editors. JBI Manual for Evidence Synthesis [Internet]. 2020 [cited 2023 jul 8]. Available from; https://synthesismanual.jbi.global.
https://synthesismanual.jbi.global... appraises the article in 9 domains (definition of cause and effect, inclusion of participants in comparisons similar or groups, presence of control group, pre and post measurements, follow-up, comparability, measurement of outcomes and analysis).

The Newcastle-Ottawa Scale (NOS)¹³13 Palmeri V, Colamesta V, La Torre G. Evaluation of methodological quality of studies. Senses Sci 2016; 3(3):235-224. for cohort studies comprises 3 domains (selection, comparability and results) giving a maximum score of 9 points if all requirements are met, reflecting the quality of the evidence generated. was employed to rate the quality of cross-sectional studies for. The NOS for case-control studies¹⁴14 Wells GA, Shea B, O'Connell D, Peterson J, Welch V, Losos M, Tugwell P. The Newcastle-Ottawa Scale (NOS) for assessing the quality of nonrandomised studies in meta-analyses [Internet]. The Ottawa Hospital, Our Research; 2021 [cited 2023 jul 8]. Available from: http://www.ohri.ca/programs/clinical_epidemiology/oxford.asp., was used to assess the quality of both cohort and case-control studies assesses 3 domains (selection, comparability and exposure), yielding 9 points if all items measuring methodological quality are met. Also, the NOS adapted for cross-sectional studies¹⁵15 Moher D, Shamseer L, Clarke M, Ghersi D, Liberati A, Petticrew M, Shekelle P, Stewart LA. Preferred reporting items for systematic review and meta-analysis protocols (PRISMA-P) 2015 statement. Systematic Rev 2015; 4:1. comprises 3 domains, yielding a score of 0-9 points on the methodological quality assessment.

The findings of the analyses of study data and quality are given in tables and charts, grouped by NPM studied. The stages of study selection and analysis were performed as depicted in the flow diagram of the literature search and study selection for review (Figure 1).

Results

A total of 25 articles were included in the review after identification during the steps of selection and analysis of publications addressing effects of NPMs on duration of labor. The methodological characteristics of the studies selected are outlined in Chart 1 ¹⁵15 Moher D, Shamseer L, Clarke M, Ghersi D, Liberati A, Petticrew M, Shekelle P, Stewart LA. Preferred reporting items for systematic review and meta-analysis protocols (PRISMA-P) 2015 statement. Systematic Rev 2015; 4:1..

The NPMs identified were hot/warm shower, water immersion, walking, breathing techniques, relaxation techniques, birth ball, massage, positions adopted by mother, acupuncture, acupressure, auriculotherapy, aromatherapy, water birth and pushing techniques during the expulsion stage. Some studies investigated a combination of these different methods.

The methods identified were grouped according to type of NPM or presented as a combination when applied in association with other methods. The influence of these NPMs on the duration of labor, or its stages, for each study reviewed is described in Chart 2.

Hot/warm shower

With regard to the hot/warm shower method, applied alone, the sole publication identified showed a reduction in the duration of the active stage of labor³⁵35 Maddady S, Mohammad-Alizadeh S, Shafaei S, Mirghafourvand M. Comparing the effects of hot shower and intravenous injection of hyoscine on the pain intensity and duration of active phase of labour in nulliparous women. Iranian J Obstetr Gynecol Infertility 2018; 12(8):QC07-QC11. and had a low risk of bias on the methodological quality analysis¹¹11 Higgins JPT, Savovic J, Page MJ, Sterne JAC. Revised Cochrane risk-of-bias tool for randomized trials (RoB 2): short version (CRIBSHEET) [Internet]. 2019 [cited 2023 jul 8]. Available from: https://methods.cochrane.org/bias/resources/rob-2-revised-cochrane-risk-bias-tool-randomized-trials.
https://methods.cochrane.org/bias/resour... .

Immersion bath

For the immersion bath approach, mixed results were reported. Three studies found no difference in duration of labor among the women who used this method¹⁷17 Eckert K, Turnbull D, MacLennan A. Immersion in water in the first stage of labor: a randomized controlled trial. Birth 2001; 28(2):84-93.^,2020 Silva FMB, Oliveira SMJV. O efeito do banho de imersão na duração do trabalho de parto. Rev Esc Enferm USP 2006; 40(1):57-63.^,2727 Liu Y, Liu Y, Huang X, Du C, Peng J, Huang P, Zhang J. A comparison of maternal and neonatal outcomes between water immersion during labor and conventional labor and delivery. BMC Pregnancy Childbirth 2014; 14:160.. On the quality analysis, one of the publications was rated as having Low risk of bias¹¹11 Higgins JPT, Savovic J, Page MJ, Sterne JAC. Revised Cochrane risk-of-bias tool for randomized trials (RoB 2): short version (CRIBSHEET) [Internet]. 2019 [cited 2023 jul 8]. Available from: https://methods.cochrane.org/bias/resources/rob-2-revised-cochrane-risk-bias-tool-randomized-trials.
https://methods.cochrane.org/bias/resour... , one as Some concerns¹²12 Tufanaru C, Munn Z, Aromataris E, Campbell J, Hopp L. Systematic reviews of effectiveness. In: Aromataris E, Lockwood C, Porritt K, Pilla B, Jordan Z, editors. JBI Manual for Evidence Synthesis [Internet]. 2020 [cited 2023 jul 8]. Available from; https://synthesismanual.jbi.global.
https://synthesismanual.jbi.global... and the other as High risk of bias¹¹11 Higgins JPT, Savovic J, Page MJ, Sterne JAC. Revised Cochrane risk-of-bias tool for randomized trials (RoB 2): short version (CRIBSHEET) [Internet]. 2019 [cited 2023 jul 8]. Available from: https://methods.cochrane.org/bias/resources/rob-2-revised-cochrane-risk-bias-tool-randomized-trials.
https://methods.cochrane.org/bias/resour... . One of the studies found no effects on the active stage of labor among nulliparous and multiparous women or on the expulsion stage in multiparous women. The same study, rated as having good methodological quality¹³13 Palmeri V, Colamesta V, La Torre G. Evaluation of methodological quality of studies. Senses Sci 2016; 3(3):235-224., observed increased duration of the expulsion stage in nulliparous women who used the technique³⁸38 Neiman E, Austin E, Tan A, Anderson CM, Chipps E. Outcomes of waterbirth in a US Hospital-Based Midwifery practice: a retrospective cohort study of water immersion during labor and birth. J Midwifery Womens Health 2020; 65(2):216-223., however, it did not show the magnitude of the method’s effect on the duration of labor.

An increase in the expulsion stage after immersion bath was documented by two studies²²22 Zanetti-Daellenbach RA, Tschudin S, Zhong XY, Holzgreve W, Lapaire O, Hösli I. Maternal and neonatal infections and obstetrical outcome in water birth. Eur J Obstet Gynecol Reprod Biol 2007; 134(1):37-43.^,3434 Ulfsdottir H, Saltvedt S, Georgsson S. Waterbirth in Sweden: a comparative study. Acta Obstet Gynecol Scand 2018; 97(3):341-348. of high methodological quality¹³13 Palmeri V, Colamesta V, La Torre G. Evaluation of methodological quality of studies. Senses Sci 2016; 3(3):235-224., one of which also showed an increase in the duration of the active stage²²22 Zanetti-Daellenbach RA, Tschudin S, Zhong XY, Holzgreve W, Lapaire O, Hösli I. Maternal and neonatal infections and obstetrical outcome in water birth. Eur J Obstet Gynecol Reprod Biol 2007; 134(1):37-43.. These studies, however, presented as a limitation the absence of a measure of the magnitude of the effect of the studied method on the duration of the labor stage.

Walking

The results of the single study investigating the effect of walking on duration of labor showed that, for every 100 meters walked in the first hour, there was a 22-minute reduction in the length of the active stage; a 10-minute reduction for the second hour, and 6-minute decrease in the third hour of labor²³23 Mamede FV, Almeida AM, Souza L, Mamede MV. A dor durante o trabalho de parto: o efeito da deambulação. Rev Lat Am Enfermagem 2007; 15(6):1157-1162., the effects were evidenced through logistic regression. This study was rated as having a low risk of bias¹²12 Tufanaru C, Munn Z, Aromataris E, Campbell J, Hopp L. Systematic reviews of effectiveness. In: Aromataris E, Lockwood C, Porritt K, Pilla B, Jordan Z, editors. JBI Manual for Evidence Synthesis [Internet]. 2020 [cited 2023 jul 8]. Available from; https://synthesismanual.jbi.global.
https://synthesismanual.jbi.global... .

Breathing techniques

Only one article addressed breathing techniques as a dedicated topic of investigation. The study in question applied the Lamaze method, involving breathing techniques applied at different levels. The strategy promoted a statistically significant reduction in the latent and active stages of labor, analyzed by comparison of means³²32 Cicek S, Basar F. The effects of breathing techniques training on the duration of labor and anxiety levels of pregnant women. Complement Ther Clin Pract 2017; 29:213-219.. However, the magnitude of the effect on the duration of labor was not shown and the methodology of the study was rated as having some concerns¹²12 Tufanaru C, Munn Z, Aromataris E, Campbell J, Hopp L. Systematic reviews of effectiveness. In: Aromataris E, Lockwood C, Porritt K, Pilla B, Jordan Z, editors. JBI Manual for Evidence Synthesis [Internet]. 2020 [cited 2023 jul 8]. Available from; https://synthesismanual.jbi.global.
https://synthesismanual.jbi.global... .

Birth ball exercises

One study involved birth ball exercises, showing a reduction in duration of the active stage of the labor process by using a Swiss ball²⁴24 Gau M-L, Chang C-Y, Tian S-H, Lin K-C. Effects of birth ball exercise on pain and self-efficacy during childbirth: a randomised controlled trial in Taiwan. Midwifery 2011; 27(6):e293-300.. It was methodologically rated as having Some concerns¹¹11 Higgins JPT, Savovic J, Page MJ, Sterne JAC. Revised Cochrane risk-of-bias tool for randomized trials (RoB 2): short version (CRIBSHEET) [Internet]. 2019 [cited 2023 jul 8]. Available from: https://methods.cochrane.org/bias/resources/rob-2-revised-cochrane-risk-bias-tool-randomized-trials.
https://methods.cochrane.org/bias/resour... , and it did not show the measure of the effect of the method on the duration of labor.

Massage

Only one article addressed massage alone, whose results showed that the technique promoted an increase in duration of labor²⁶26 Gallo RBS, Santana LS, Ferreira CHJ, Marcolin AC, Polineto OB, Duarte G, Quintana SM. Massage reduced severity of pain during labour: a randomised trial. J Physiother 2013; 59(2):109-116.. The trial in question was rated as having Low risk of bias¹¹11 Higgins JPT, Savovic J, Page MJ, Sterne JAC. Revised Cochrane risk-of-bias tool for randomized trials (RoB 2): short version (CRIBSHEET) [Internet]. 2019 [cited 2023 jul 8]. Available from: https://methods.cochrane.org/bias/resources/rob-2-revised-cochrane-risk-bias-tool-randomized-trials.
https://methods.cochrane.org/bias/resour... .

Maternal positions adopted

In one publication, the use of dorsal decubitus in the active stage was associated with shorter labor time²⁹29 Desseauve D, Gachon B, Bertherat P, Fradet L, Lacouture P, Pierre F. Dans quelle position les femmes accouchent-elles en 2015? Résultats d'une étude prospective régionale multicentrique. Gynécologie Obstétrique Fertil 2016; 44(10):548-556., where the study in question had Good methodological quality¹⁴14 Wells GA, Shea B, O'Connell D, Peterson J, Welch V, Losos M, Tugwell P. The Newcastle-Ottawa Scale (NOS) for assessing the quality of nonrandomised studies in meta-analyses [Internet]. The Ottawa Hospital, Our Research; 2021 [cited 2023 jul 8]. Available from: http://www.ohri.ca/programs/clinical_epidemiology/oxford.asp.. In another study, rated as having High risk of bias¹¹11 Higgins JPT, Savovic J, Page MJ, Sterne JAC. Revised Cochrane risk-of-bias tool for randomized trials (RoB 2): short version (CRIBSHEET) [Internet]. 2019 [cited 2023 jul 8]. Available from: https://methods.cochrane.org/bias/resources/rob-2-revised-cochrane-risk-bias-tool-randomized-trials.
https://methods.cochrane.org/bias/resour... , the semi-sitting position had no effect on duration of labor¹⁶16 Bomfim-Hyppólito S. Influence of the position of the mother at delivery over some maternal and neonatal outcomes. Int J Gynecol Obstetr 1998; 21(63):S67-S73., however without presenting the magnitude of the effect of the method over time.

Maternal mobility

Changes in the position of the mother during labor were associated with longer labor times²⁹29 Desseauve D, Gachon B, Bertherat P, Fradet L, Lacouture P, Pierre F. Dans quelle position les femmes accouchent-elles en 2015? Résultats d'une étude prospective régionale multicentrique. Gynécologie Obstétrique Fertil 2016; 44(10):548-556. in a study of High methodological quality¹⁴14 Wells GA, Shea B, O'Connell D, Peterson J, Welch V, Losos M, Tugwell P. The Newcastle-Ottawa Scale (NOS) for assessing the quality of nonrandomised studies in meta-analyses [Internet]. The Ottawa Hospital, Our Research; 2021 [cited 2023 jul 8]. Available from: http://www.ohri.ca/programs/clinical_epidemiology/oxford.asp..

Acupuncture/Acupressure/Auriculotherapy

In a study with low risk of bias¹¹11 Higgins JPT, Savovic J, Page MJ, Sterne JAC. Revised Cochrane risk-of-bias tool for randomized trials (RoB 2): short version (CRIBSHEET) [Internet]. 2019 [cited 2023 jul 8]. Available from: https://methods.cochrane.org/bias/resources/rob-2-revised-cochrane-risk-bias-tool-randomized-trials.
https://methods.cochrane.org/bias/resour... , acupuncture was shown to reduce the length of time elapsed between rupture of membranes and birth²¹21 Gaudernack LC, Forbord S, Hole E. Acupuncture administered after spontaneous rupture of membranes at term significantly reduces the length of birth and use of oxytocin: a randomized controlled trial. Acta Obstet Gynecol Scand 2006; 85(11):1348-1353.. Application of acupressure at specific points also reduced mean labor time in the intervention group, with the effect reaching statistical significance²⁸28 Mafetoni RR, Shimo AKK. Efeitos da acupressão na evolução do parto e taxa de cesárea: ensaio clínico randomizado. Rev Saude Publica 2015; 49:9., but the magnitude of the effect on the duration of labor was not shown. The study was rated as having Low risk of bias¹¹11 Higgins JPT, Savovic J, Page MJ, Sterne JAC. Revised Cochrane risk-of-bias tool for randomized trials (RoB 2): short version (CRIBSHEET) [Internet]. 2019 [cited 2023 jul 8]. Available from: https://methods.cochrane.org/bias/resources/rob-2-revised-cochrane-risk-bias-tool-randomized-trials.
https://methods.cochrane.org/bias/resour... . In another study, also classified as having Low risk of bias¹¹11 Higgins JPT, Savovic J, Page MJ, Sterne JAC. Revised Cochrane risk-of-bias tool for randomized trials (RoB 2): short version (CRIBSHEET) [Internet]. 2019 [cited 2023 jul 8]. Available from: https://methods.cochrane.org/bias/resources/rob-2-revised-cochrane-risk-bias-tool-randomized-trials.
https://methods.cochrane.org/bias/resour... , the auriculotherapy technique had no effect on average labor time³⁶36 Mafetoni RR, Jacob LMS, Jorge HMF, Shimo AKK. Efeitos da auriculoterapia no tempo de trabalho de parto e taxa de cesárea: ensaio clínico randomizado. REME 2018; 22:e1139..

Water birth

Immersion during the expulsion stage shortened length of labor in 3 studies²²22 Zanetti-Daellenbach RA, Tschudin S, Zhong XY, Holzgreve W, Lapaire O, Hösli I. Maternal and neonatal infections and obstetrical outcome in water birth. Eur J Obstet Gynecol Reprod Biol 2007; 134(1):37-43.^,2525 Cortes E, Basra R, Kelleher CJ. Waterbirth and pelvic floor injury: a retrospective study and postal survey using ICIQ modular long form questionnaires. Eur J Obstet Gynecol Reprod Biol 2011; 155(1):27-30.^,3434 Ulfsdottir H, Saltvedt S, Georgsson S. Waterbirth in Sweden: a comparative study. Acta Obstet Gynecol Scand 2018; 97(3):341-348.. This also held true for nulliparous women, whose labor process was shortened by use of the technique³⁸38 Neiman E, Austin E, Tan A, Anderson CM, Chipps E. Outcomes of waterbirth in a US Hospital-Based Midwifery practice: a retrospective cohort study of water immersion during labor and birth. J Midwifery Womens Health 2020; 65(2):216-223.. However, in a study conducted at two different hospitals, a reduction in the expulsion stage was seen at one site, while no effect was found for the other hospital¹⁸18 Schröcksnadel H, Kunczicky V, Meier J, Brezinka C, Oberaigner W. Water Birth: experience at a university clinic and a district hospital in Austria. Gynakol Geburtshilfliche Rundsch 2003; 43(1):7-11.. These articles did not show the magnitude of effect on delivery time but were classified as having good methodological quality¹³13 Palmeri V, Colamesta V, La Torre G. Evaluation of methodological quality of studies. Senses Sci 2016; 3(3):235-224..

Pushing techniques in expulsion stage

Passive descent (delayed pushing) and spontaneous pushing were associated with longer expulsion times in 2 articles included in the review³⁰30 Vaziri F, Arzhe A, Asadi N, Pourahmad S, Moshfeghy Z. Spontaneous pushing in lateral position versus valsalva maneuver during second stage of labor on maternal and fetal outcomes: a randomized clinical trial. Iran Red Crescent Med J 2016; 18(10):e29279.^,3131 Koyucu RG, Demirci N. Effects of pushing techniques during the second stage of labor: A randomized controlled trial. Taiwan J Obstet Gynecol 2017; 56(5):606-612.. The 2 studies were rated as having Some concerns and Low risk of bias, respectively¹¹11 Higgins JPT, Savovic J, Page MJ, Sterne JAC. Revised Cochrane risk-of-bias tool for randomized trials (RoB 2): short version (CRIBSHEET) [Internet]. 2019 [cited 2023 jul 8]. Available from: https://methods.cochrane.org/bias/resources/rob-2-revised-cochrane-risk-bias-tool-randomized-trials.
https://methods.cochrane.org/bias/resour... , but they did not show the measure of the effect of the method on the time of delivery.

Techniques used in association

Some of the studies reviewed explored the influence of the application of more than one NPM, used in association, on duration of labor. The application of breathing techniques in association with relaxation methods led to a longer latent stage of labor in the experimental group¹⁹19 Almeida NAM, Sousa JT, Bachion MM, Silveira NA. Utilização de técnicas de respiração e relaxamento para alívio de dor e ansiedade no processo de parturição. Rev Lat Am Enferm 2005; 13(1):52-58., however, it did not measure the magnitude of the effect on delivery time and was classified with some methodological concerns¹¹11 Higgins JPT, Savovic J, Page MJ, Sterne JAC. Revised Cochrane risk-of-bias tool for randomized trials (RoB 2): short version (CRIBSHEET) [Internet]. 2019 [cited 2023 jul 8]. Available from: https://methods.cochrane.org/bias/resources/rob-2-revised-cochrane-risk-bias-tool-randomized-trials.
https://methods.cochrane.org/bias/resour... .

In another study, rated as having Low risk of bias¹¹11 Higgins JPT, Savovic J, Page MJ, Sterne JAC. Revised Cochrane risk-of-bias tool for randomized trials (RoB 2): short version (CRIBSHEET) [Internet]. 2019 [cited 2023 jul 8]. Available from: https://methods.cochrane.org/bias/resources/rob-2-revised-cochrane-risk-bias-tool-randomized-trials.
https://methods.cochrane.org/bias/resour... , the hot/warm shower technique was combined with birth ball exercises, revealing no effect on duration of labor³⁷37 Cavalcanti ACV, Henrique AJ, Brasil CM, Gabrielloni MC, Barbieri M. Terapias complementares no trabalho de parto: ensaio clínico randomizado. Rev Gaucha Enferm 2019; 40:e20190026..

One study investigating the use of ball exercises, together with lumbosacral massage and hot/warm shower, showed a reduction in length of the expulsion stage, but had no effect on the active stage⁹9 Makvandi S, Mirzaiinajmabadi K, Sadeghi R, Mahdavian M, Karimi L. Meta-analysis of the effect of acupressure on duration of labor and mode of delivery. Int J Gynecol Obstet 2016; 135(1):5-10.. The study in question had Low risk of bias¹¹11 Higgins JPT, Savovic J, Page MJ, Sterne JAC. Revised Cochrane risk-of-bias tool for randomized trials (RoB 2): short version (CRIBSHEET) [Internet]. 2019 [cited 2023 jul 8]. Available from: https://methods.cochrane.org/bias/resources/rob-2-revised-cochrane-risk-bias-tool-randomized-trials.
https://methods.cochrane.org/bias/resour... .

In one study, rated as having Low risk of bias¹²12 Tufanaru C, Munn Z, Aromataris E, Campbell J, Hopp L. Systematic reviews of effectiveness. In: Aromataris E, Lockwood C, Porritt K, Pilla B, Jordan Z, editors. JBI Manual for Evidence Synthesis [Internet]. 2020 [cited 2023 jul 8]. Available from; https://synthesismanual.jbi.global.
https://synthesismanual.jbi.global... , immersion bath was combined with ball exercises, aromatherapy using essential oil of lavender, and adoption of the vertical position in the expulsion stage. The association of NPMs was shown to reduce the active stage of labor but had no effect on the expulsion stage³³33 Makvandi S, Mirzaiinajmabadi K, Mirteimoori M, Esmaily H. Effect of normal physiologic childbirth program in mother-friendly hospitals on duration of labor. Electron J Gen Med 2018; 15(3):em21., however, it is important to emphasize that the study did not present the magnitude of the effect on the duration of labor.

Lastly, one of the studies reviewed, in which mothers kept moving position, switching vertical postures during labor, had shorter labor times⁷7 Bio E, Bittar RE, Zugaib M. Influência da mobilidade materna na duração da fase ativa do trabalho de parto. Rev Bras Ginecol Obstetr 2006; 28(11):671-679.. This study was rated as having Some concerns methodologically¹¹11 Higgins JPT, Savovic J, Page MJ, Sterne JAC. Revised Cochrane risk-of-bias tool for randomized trials (RoB 2): short version (CRIBSHEET) [Internet]. 2019 [cited 2023 jul 8]. Available from: https://methods.cochrane.org/bias/resources/rob-2-revised-cochrane-risk-bias-tool-randomized-trials.
https://methods.cochrane.org/bias/resour... , and the magnitude of the effect on the duration of labor was not shown, only the comparison of means.

Discussion

Delivery within a hospital setting is characterized by the use of a host of different technologies and procedure intended to ensure the safety of both mother and newborn. However, modern obstetrics does not treat the pregnancy period, labor or birth as natural expressions of health³⁹39 Brasil. Ministério da Saúde (MS). Secretaria de Ciência, Tecnologia e Insumos Estratégicos. Departamento de Gestão e Incorporação de Tecnologias em Saúde. Diretrizes nacionais de assistência ao parto normal: Relatório de Recomendação. Brasília: MS; 2016..

Under this model, mothers and newborns are exposed to major interventions which should be used in a more controlled rational manner only when necessary, yet are adopted as part of routine practice. This overuse of interventions, such as the oxytocin, episiotomy, cesarean section, nasopharyngeal aspiration, among others, disregard emotional, human and cultural aspects involved in the process of childbirth³⁹39 Brasil. Ministério da Saúde (MS). Secretaria de Ciência, Tecnologia e Insumos Estratégicos. Departamento de Gestão e Incorporação de Tecnologias em Saúde. Diretrizes nacionais de assistência ao parto normal: Relatório de Recomendação. Brasília: MS; 2016..

In 2004, the Ministry of Health launched the National Policy for Humanization (PNH), tackling overly interventionist practices, with guidance for professional conduct to respect the physiological aspects of labor. These guidelines acknowledge social and cultural aspects, seek to promote health, and provide the mother and family with emotional support, ensuring successful labor and childbirth⁴⁰40 Dias MA, Domingues RM. Desafios na implantação de uma política de humanização da assistência hospitalar ao parto. Cien Saude Colet 2005; 10(3):699-705..

Although the PNH is valued in theory, good practices in labor assistance are not always applied. According to data from the “Nascer no Brasil” survey, only 5.6% of normal deliveries are performed without some type of intervention, where practices considered inappropriate and even those that should be abolished, such as the Kristeller maneuver, continue to be applied⁴¹41 Leal MC, Pereira APE, Domingues RMSM, Theme Filha MM, Dias MAB, Nakamura-Pereira M, Bastos MH, Gama SGN. Intervenções obstétricas durante o trabalho de parto e parto em mulheres brasileiras de risco habitual. Cad Saude Publica 2014; 30(1):17-47..

It is important to emphasize that these interventions are not restricted to normal delivery, but also to the routine use of various practices during labor that need to be reviewed in order to restore women’s autonomy and well-being⁴²42 Brasil. Ministério da Saúde (MS). Secretaria de Vigilância em Saúde. Uma análise da situação de saúde e a vigilância da saúde da mulher. Brasília: MS; 2012.^,4343 Stewart M, McCandlish R, Henderson J, Brocklehurst P. Review of evidence about clinical, psychosocial and economic outcomes for women with straightforward pregnancies who plan to give birth in a midwife-led birth centre, and outcomes for their babies [Internet]. National Perinatal Epidemiology Unit: University of Oxford; 2005 [cited 2023 jul 8]. Available from: https://www.npeu.ox.ac.uk/assets/downloads/reports/Birth-Centre-Review.pdf., because when a labor of delivery is accelerated can have consequences for the parturient.

Also, the extension of the stages of labor can lead to the indication of a cesarean section, due to the risk of complications. The delay in the expulsive phase tends to occur due to maternal exhaustion, inertia or hypoactivity of the uterus, and due to the inability to properly contract the abdominal muscles. Thus, when performing a cesarean section, there is a risk of infection, hemorrhage, pulmonary embolism and disorders during anesthesia and even the consequent maternal death²2 Brasil. Ministério da Saúde (MS). Secretaria de Políticas da Saúde. Parto, aborto e puerpério: assistência humanizada à mulher. Brasília: MS, FEBRASGO, ABENFO; 2001..

In addition, complications associated with the long period of labor may include postpartum hemorrhage due to uterine atony. Therefore, the use of NFMs during this process tends to promote satisfactory results, reducing the use of medication and making parturients calmer and more relaxed, through specific techniques aimed at comfort and reduction of the duration of labor⁴⁴44 Dias EG, Ferreira AR, Martins AM, Nunes MM, Alves JC. Eficiência de métodos não farmacológicos para alívio da dor no trabalho de parto normal. Enferm Foco 2018; 9(2):35-39..

Thus, the present study investigated, through a systematic review, the effect of MNFs used alone and/or in conjunction with other methods to reduce the duration of labor and/or some stage of labor.

The bath was the method more commonly found in studies applying it in conjunction with other techniques, such as birth ball exercises³⁷37 Cavalcanti ACV, Henrique AJ, Brasil CM, Gabrielloni MC, Barbieri M. Terapias complementares no trabalho de parto: ensaio clínico randomizado. Rev Gaucha Enferm 2019; 40:e20190026.. A literature review concluded that the benefits of hot/warm showers on duration of labor were greater when the method was combined with the use of the birth ball⁴⁵45 Silva CA, Lara SRG. Uso do banho de aspersão associado à bola suíça como método de alívio da dor na fase ativa do trabalho de parto. BrJP 2018; 1:167-170..

For the immersion bath approach, mixed results were reported¹⁷17 Eckert K, Turnbull D, MacLennan A. Immersion in water in the first stage of labor: a randomized controlled trial. Birth 2001; 28(2):84-93.^,2020 Silva FMB, Oliveira SMJV. O efeito do banho de imersão na duração do trabalho de parto. Rev Esc Enferm USP 2006; 40(1):57-63.^,2727 Liu Y, Liu Y, Huang X, Du C, Peng J, Huang P, Zhang J. A comparison of maternal and neonatal outcomes between water immersion during labor and conventional labor and delivery. BMC Pregnancy Childbirth 2014; 14:160.^,3838 Neiman E, Austin E, Tan A, Anderson CM, Chipps E. Outcomes of waterbirth in a US Hospital-Based Midwifery practice: a retrospective cohort study of water immersion during labor and birth. J Midwifery Womens Health 2020; 65(2):216-223., this association of this method with others helps to delay the use of pharmacological agents, allowing a more active participation of the parturient woman and her companion²⁰20 Silva FMB, Oliveira SMJV. O efeito do banho de imersão na duração do trabalho de parto. Rev Esc Enferm USP 2006; 40(1):57-63..

These techniques are considered safe, with no adverse effects on obstetric outcomes, and are also associated with greater satisfaction with the duration of the process of labor and expulsion⁸8 Gallo RBS, Santana LS, Marcolin AC, Duarte G, Quintana SM. Sequential application of non-pharmacological interventions reduces the severity of labour pain, delays use of pharmacological analgesia, and improves some obstetric outcomes: a randomised trial. J Physiother 2018; 64(1):33-40..

However, the scientific literature points out that the exercise of the birthing ball confers benefits to the woman, in the act of standing, contributing to the reduction of the time of parturition, with shortening of the active phase²⁴24 Gau M-L, Chang C-Y, Tian S-H, Lin K-C. Effects of birth ball exercise on pain and self-efficacy during childbirth: a randomised controlled trial in Taiwan. Midwifery 2011; 27(6):e293-300.. In this way, walking also proved to be effective in the present study for reducing the duration of both the dilation and expulsion phases²⁵25 Cortes E, Basra R, Kelleher CJ. Waterbirth and pelvic floor injury: a retrospective study and postal survey using ICIQ modular long form questionnaires. Eur J Obstet Gynecol Reprod Biol 2011; 155(1):27-30..

Maternal mobility was also associated with a decrease in labor⁴⁶46 Osório SMB, Silva Júnior LG, Nicolau AIO. Avaliação da efetividade de métodos não farmacológicos no alívio da dor do parto. Rev Rene 2014; 15(1):174-184., when combined with alternating vertical postures, it was presented as a method for reducing the active phase of labor⁷7 Bio E, Bittar RE, Zugaib M. Influência da mobilidade materna na duração da fase ativa do trabalho de parto. Rev Bras Ginecol Obstetr 2006; 28(11):671-679.. The freedom to choose the position, however, has had conflicting results, as it means that the mother can choose the position she is most comfortable in at any time during labor, be it vertical, horizontal or a combination of the two.

Also suggesting that a vertical or horizontal decubitus influences progression of labor, a literature review found most studies reported that non-horizontal positions used during expulsion reduced the duration of birth, while almost half showed that adopting the vertical position shortened the process. In the review, the best evidence suggested that positions that exploited gravity shortened the process of giving birth, directing the fetus to the birth canal⁴⁷47 Vargas Londoño VF, Rodríguez Castiblanco JP, Corredor Acosta MT, Vallejo Astudillo NM. Ventajas y desventajas del parto vertical en contraste con el parto horizontal: una revisión de la literatura. Investig En Enferm Imagen Desarro 2018; 20(1):1-13..

In contrast to what this review found, the application of a progressive stretching method called obstetric psychoprophylaxis normally reduces the duration, ensuring to shorten the dilation and expulsion phases, thus shortening the delivery process as a whole⁴⁶46 Osório SMB, Silva Júnior LG, Nicolau AIO. Avaliação da efetividade de métodos não farmacológicos no alívio da dor do parto. Rev Rene 2014; 15(1):174-184.. The prescribed Lamaze method, when associated with nursing intervention, also promotes shorter labor times⁴⁸48 Wu C, Ge Y, Zhang X. Du Y, He S, Ji Z, Lang H. The combined effects of Lamaze breathing training and nursing intervention on the delivery in primipara: A PRISMA systematic review meta-analysis. Medicine (Baltimore) 2021; 100(4):e23920..

In addition, acupuncture and acupressure at specific points can reduce the duration of labor²¹21 Gaudernack LC, Forbord S, Hole E. Acupuncture administered after spontaneous rupture of membranes at term significantly reduces the length of birth and use of oxytocin: a randomized controlled trial. Acta Obstet Gynecol Scand 2006; 85(11):1348-1353.^,2828 Mafetoni RR, Shimo AKK. Efeitos da acupressão na evolução do parto e taxa de cesárea: ensaio clínico randomizado. Rev Saude Publica 2015; 49:9., shortening the active stage by an average of 1.21 hours and the second stage by 5.81 minutes⁹9 Makvandi S, Mirzaiinajmabadi K, Sadeghi R, Mahdavian M, Karimi L. Meta-analysis of the effect of acupressure on duration of labor and mode of delivery. Int J Gynecol Obstet 2016; 135(1):5-10., specifically attributed to the first method. According to Chinese medicine, there are necessary balances for the initiation and progression of the delivery process, where vital energy and blood functions are essential; thus, these methods are recommended to help balance the physical components of the body⁴⁹49 Amir N, Berger R, Grinfeld T, Kaner P, Gabinet Y. Efficacy comparison between Chinese medicine's labor inducement methods and conventional methods customary in hospitals. Harefuah 2015; 154(1):47-51..

Finally, water birth is another method that reduces the expulsive time¹⁸18 Schröcksnadel H, Kunczicky V, Meier J, Brezinka C, Oberaigner W. Water Birth: experience at a university clinic and a district hospital in Austria. Gynakol Geburtshilfliche Rundsch 2003; 43(1):7-11.^,2222 Zanetti-Daellenbach RA, Tschudin S, Zhong XY, Holzgreve W, Lapaire O, Hösli I. Maternal and neonatal infections and obstetrical outcome in water birth. Eur J Obstet Gynecol Reprod Biol 2007; 134(1):37-43.^,2525 Cortes E, Basra R, Kelleher CJ. Waterbirth and pelvic floor injury: a retrospective study and postal survey using ICIQ modular long form questionnaires. Eur J Obstet Gynecol Reprod Biol 2011; 155(1):27-30.^,3434 Ulfsdottir H, Saltvedt S, Georgsson S. Waterbirth in Sweden: a comparative study. Acta Obstet Gynecol Scand 2018; 97(3):341-348.^,3838 Neiman E, Austin E, Tan A, Anderson CM, Chipps E. Outcomes of waterbirth in a US Hospital-Based Midwifery practice: a retrospective cohort study of water immersion during labor and birth. J Midwifery Womens Health 2020; 65(2):216-223., however, the scientific literature states that its effects are still inconclusive⁵⁰50 American Academy of Pediatrics Committee on Fetus and Newborn; American College of Obstetricians and Gynecologists Committee on Obstetric Practice. Immersion in water during labor and delivery. Pediatrics 2014; 133(4):758-761.. Similarly, delayed expulsive efforts or spontaneous pushing were associated with a longer second step of almost an hour⁵¹51 Tuuli MGM, Frey HA, Odibo AOM, Macones GAM, Cahill AGM (). Immediate compared with delayed pushing in the second stage of labor: a systematic review and meta-analysis. Obstet Gynecol 2012; 120(3):660-668..

The diversity of analyzed methods and the heterogeneity of the studies constituted a limitation of the present study, making comparisons and clarity impossible in relation to each MNP investigated.

Conclusions

The MNFs presented in this study are strategies used for better management, with a view to good practices in labor and birth care that enable a care model to be implemented by managers and health professionals, in the elimination of unnecessary interventions for parturients.

Among the methods presented in this study, showering, walking, exercises with the birth ball, breathing techniques, maternal mobility, acupuncture and acupressure, aromatherapy, supine position, immersion bath and water birth reduced the duration of labor and/or delivery when applied alone. Also, the association of methods, such as immersion bath, ball exercises, aromatherapy, vertical postures and maternal mobility with alternate vertical postures, shortened the time of delivery or any of its phases.

On the other hand, auriculotherapy, hot/warm bath associated with ball exercises did not affect the duration of labor, while immersion bath during labor, massage and spontaneous pushing increased the duration of labor. Combining breathing with relaxation techniques also promoted longer labor.

It is noteworthy that this diversity of analyzed methods and the heterogeneity of the selected articles in the present study verified a limitation, making it impossible to make detailed comparisons in relation to each identified NFM and the analysis of the magnitude of the effect of the strategies on the duration of labor.

However, it should be noted that this overview of the use of these methods can contribute to reflection on the practice of health professionals in relation to the assistance provided to women in labor, with the proposition of indicators that allow the use of this practice; despite the scientific literature pointing out the incipience of investigations that address the difficulties of implementation and the necessary advances for its execution as recommended.

References

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