Pain management in the first stage of labour using sensory stimulation

Labour pain is a sensory and emotional experience associated with labour and delivery (Herdman and Kamitsuru, 2014). Chow et al (2013) states that pain is a subjective experience, a complex interaction between physiological, spiritual, sensory, behavioural, cognitive, psychological and cultural influences. Labour pain is caused by cervical dilation, uterine muscle hypoxia, which causes decreased perfusion during contractions, pressure on the urethra, bladder, rectum and pelvic floor muscles (Ricci et al, 2013).

During labour, the level of pain experienced is based on the mother's perception (Yulianingsih et al, 2019). A mother's perception of pain is influenced by her experience, fatigue, anticipation of pain, support, environment, cultural expectations, emotional level and anxiety (Lowdermilk et al, 2013).

The labour process consists of four stages, stage I to stage IV. The first stage of labour lasts the longest (Kurniawati et al, 2016) and in a primigravida, lasts for an average of 12 hours, while multigravidas experience labour for half this time on average (Ricci et al, 2013). The first stage of labour is divided into three phases. According to Chow et al (2013), the first is the latent phase, where the cervix dilates up to 3cm and contractions occur every 5–10 minutes, lasting for 30–45 seconds. The next phase is the active phase, where the cervix dilates 4–7cm, contractions occur every 2–5 minutes and last 45–60 seconds. The last phase is the transitional phase, where dilation is between 8–10cm, contractions occur every 1–2 minutes and last 60–90 seconds (Chow et al, 2013). Recent literature and studies have stated that the active phase begins at 6 cm of cervical dilation (Shukla et al, 2020; Hutchison et al, 2022). This change in the definition of the active phase affects labour management and the identification of abnormal labour. For example, the risk of misdiagnosing dystocia and overuse of labour-accelerating interventions is found if the Friedman criteria (cervical dilation occurs at a rate of 1cm or more per hour) are implemented. This can increase the risk of unnecessary intervention for the mother and fetus (Shukla et al, 2020).

Contractions cause pain that increases to a certain intensity, then decreases and disappears; the peak of first stage labour pain occurs in the active phase (Reeder et al, 2018). Studies have shown that labour pain in the first stage's active phase ranges from moderate to severe pain, although Rejeki et al (2017) reported that the majority (78%) experience severe pain.

Severe labour pain can have several effects on a mother; they may feel uncomfortable, be more susceptible to stress and are at risk for postpartum depressive disorders (Tzeng et al, 2017). Another effect of severe labour pain is increased demand for oxygen, increased maternal blood pressure and reduced intestinal motility, leading to increased catecholamines that can interfere with uterine contractions, leading to prolonged labour (Anita, 2017). Severe labour pain also affects the fetus, potentially causing hypoxia, metabolic acidosis, cognitive and emotional disorders and even death (Liu and Wang, 2020).

One of the roles of maternity nurses and midwives during the labour process is to carry out comfortable labour management (Chow et al, 2013). Maternity nurses and midwives are expected to provide comfort to mothers in labour using pain management that does not have a negative impact on the fetus (Ricci et al, 2013). Previous systematic reviews have reported on the effectiveness of labour pain management with water immersion, massage, ambulation, position, acupuncture, acupressure, electrical stimulation, water injection, education, support and attention (Chaillet et al, 2014). The provision of non-pharmacological interventions for labour pain can increase maternal comfort and satisfaction, provide calm and reduce pain during labour (Thomson et al, 2019). Non-pharmacological interventions are safe, non-invasive and do not cause harm to the patient (Jones, 2012).

One strategy for non-pharmacological labour pain is to provide sensory stimuli (Lowdermilk et al, 2013). Sensory stimulation aims to improve the body's response to pain (Keliat, 2015). Details of the advantages and disadvantages of the provision of non-pharmacological interventions to patients with labour pain are not known. This makes it difficult for care providers to choose a method of non-pharmacological pain therapy, especially for labour pain. Therefore, this review aimed to assess evidence from previous clinical trials to be used as a basis for providing non-pharmacological supportive therapy during labour.

Methods

The article search was conducted in January 2021 using the population/problem/patient, intervention, comparison, outcome, study design strategy. The type of reporting used was preferred reporting items for systematic reviews and meta-analysis.

Search strategy

The keywords used in the study were (labour pain OR labour pain) AND first stage labour AND (pain management OR pain intervention) AND randomized controlled trial NOT (systematic review OR meta-analytic). Primary data sources used to search for articles included the Garuda portal, the Perpustakaan Nasional Republik Indonesia e-resource, the Cochrane Central Register of Controlled Trials and Pubmed.

Inclusion and exclusion criteria

The inclusion criteria for this study were original randomised controlled trials published between 2014 and 2020 in English, where the minimum sample size was 30 and the study outcome was rated on a pain scale. Articles where the full text was not available were excluded.

Quality assessment

For each included study, data were extracted, the validity and quality were assessed and the work of each researcher was verified. The quality of articles was evaluated based on the Critical Appraisal Skills Program (2020) randomised controlled trials checklist. According to the checklist, the quality assessment focuses on the research design, methodology, results and whether the results can be applied (Table 1).

Critical assessment

This systematic literature review included intervention studies. According to the Joanna Briggs Institute (2014), the highest level of evidence for effectiveness is experimental designs. The entire article reviewed randomised controlled trials, which fall into group 1c.

Results

A total of 1352 references and 15 full text articles were screened and subjected to quality assessment, and 10 articles met the criteria (Figure 1). A summary of the chosen articles is shown in Table 2. Four were conducted in Iran, two in Turkey, one in Thailand, one in Egypt, one in Italy and one in the USA.

The selected articles stated that the intervention used in the trial effectively reduced labour pain during the first stage. Five reports used nulliparous participants (Yazdkhasti and Pirak, 2016; Hamdamian et al, 2018; Esmaelzadeh-Saeieh et al, 2018; Buglione et al, 2020; Wong et al, 2021), four articles used primiparous women (Simavli et al, 2014; Mansour Lamadah, 2016; Tanvisut et al, 2018; Türkmen et al, 2020) and one did not explicitly describe the parity of participants (Vakilian et al, 2018).

The articles examined five different interventions in the first stage of labour, to manage pain with sensory stimulation. These interventions were aromatherapy (Mansour Lamadah, 2016; Yazdkhasti and Pirak, 2016; Hamdamian et al, 2018; Esmaelzadeh-Saeieh et al, 2018; Tanvisut et al, 2018), music therapy (Simavli et al, 2014; Buglione et al, 2020), breathing (Vakilian et al, 2018), focus (Türkmen et al, 2020) and virtual reality (Wong et al, 2021). Each intervention had advantages and disadvantages to being applied in midwifery service settings.

Aromatherapy

The aromatherapy intervention was applied in five of the reviewed articles to reduce the first stage of labour pain (Mansour Lamadah, 2016; Yazdkhasti and Pirak, 2016; Esmaelzadeh-Saeieh et al, 2018; Hamdamian et al, 2018; Tanvisut et al, 2018). The articles used different types of aromatherapy; Tanvisut et al (2018) used citrus, jasmine, rose and lavender, Mansour Lamadah (2016) and Yazdkhasti and Pirak (2016) used lavender, Hamdamian et al (2018) used Rosa damascena and Esmaelzadeh-Saeieh et al (2018) used Boswellia carterii.

Aromatherapy was given in a number of different ways: by placing it on gauze and then on the collar (Esmaelzadeh-Saeieh et al, 2018; Hamdamian et al, 2018), using a diffuser (Tanvisut et al, 2018), combined with massage (Mansour Lamadah, 2016) or rubbing on the hand (Yazdkhasti and Pirak, 2016).

The reported advantages of the aromatherapy interventions were that they were effective, safe, easy to use, cheap, non-invasive, did not cause side effects and helped relaxation.

Music therapy

Two articles described the use of music therapy to manage first stage labour pain (Simavli et al, 2014; Buglione et al, 2020). Both articles allowed respondents to choose the music they listened to. The difference between the two studies was in the tools used, one used headphones (Simavli et al, 2014) and the other used speakers (Buglione et al, 2020).

Neither article gave an explanation of the specific type of music used; music from various countries were used as an intervention. The advantages of music intervention for labour pain included being practical, safe, easy, non-invasive and that it improved maternal wellbeing.

Breathing

One article described the use of a breathing control technique combined with lavender aromatherapy (Vakilian et al, 2018). This study showed that the technique combined with aromatherapy was effective in reducing labour pain at 9–10cm dilation when compared to the control group, who were advised to use a breathing technique combined with a sterile water nebuliser.

Focus

One intervention focused on Maryam's flowers (Türkmen et al, 2020). This technique involves soaking Maryam's flowers and placing them in the delivery room. The mother is told to focus on opening, much as the flowers' petals do in water, during the labour process.

The drawbacks of this method were that it could only be given to primigravida patients who were still in early labour, as multiparous labour can be faster than nulliparous, so birth may occur before the flowers' petals fully open. The success of this intervention was influenced by the culture and beliefs of pregnant women, as its efficacy depended on whether a mother believed it would help.

Virtual reality

The final intervention used was virtual reality (Wong et al, 2021). This intervention combines visual and auditory stimuli; the subject may choose the object of visualisation. The advantage of this intervention is that it is effective for first-stage labour pain and has no side effects. The weakness of this research was that the intervention required expensive equipment and special expertise.

Discussion

This literature review examined 10 randomised controlled trials that reported on sensory stimulation interventions to manage labour pain in the first stage of labour.

Aromatherapy

Based on the articles reviewed in the present study, interventions using aromatherapy appear to be effective in reducing the first stage of labour pain. Aromatherapy molecules inhaled through the respiratory tract will stimulate the limbic system to release endorphins, enkephalins and serotonin from the system, reducing pain and providing a sense of calm (Chughtai et al, 2018). It decreases levels of corticotropin-releasing hormone, affecting the olfactory tract in the hypothalamus and reducing anxiety (Ali et al, 2015). Anxiety is closely related to pain, as it can increase pain sensitivity and decrease pain tolerance (Esmaelzadeh-Saeieh et al, 2018).

In all reviewed studies of aromatherapy interventions, the aromatherapy used diluted essence. Giving concentrated essence in aromatherapy can cause skin irritation (Yazdkhasti and Pirak, 2016). The most commonly used aromatherapy scent was lavender. Lavender is one of the safest forms of aromatherapy, and there has been no report of toxicity (Mori et al, 2016).

This intervention can be carried out in hospitals and private practice midwifery as it can uses straightforward tools, and aromatherapy extract is usually easily available.

Music therapy

Music therapy can also be used to reduce labour pain in the first stage (Buglione et al, 2020). Music therapy is based on providing two perceptions during labour: the music and the pain. Music is perceived by the brain before pain impulses and the brain's concentration and response to pain decreases (Kimber et al, 2008). Music therapy was shown to help women cope with labour pain and improves wellbeing during labour.

Xavier and Viswanath (2016) found that music therapy is an effective non-pharmacological therapy for labour pain; the intervention does not require special training, is easy to provide and is inexpensive. Music therapy is a simple, economical and effective method of pain management (Gokyildiz Surucu et al, 2018). The article in the present literature review that used music therapy provided varied music, which was adjusted to the patient's preference. This intervention is simple to apply in various healthcare services; the choice of music can also be adjusted. This intervention is therefore likely to be readily accepted by women in multiple countries because of the flexible options for music type.

Breathing

Breathing control interventions can also be used to reduce pain during the first stage of labour. This intervention is elementary, although it is more effective when combined with other interventions (Vakilian et al, 2018). The physiological mechanism of breathing is a protective action, as it is a fight-or-flight reflex triggered by the central nervous system. Abdominal breathing stimulates the parasympathetic nerves, which affects blood circulation and triggers the release of endorphins to decrease the heart rate. This reduces levels of the hormone cortisol, which can increase calm (Baljon et al, 2020). Breathing techniques during the first stage of labour can promote relaxation of the abdominal wall, enlarging the abdominal cavity. This reduces the discomfort caused by friction between the uterus and the abdominal wall during contractions (Lowdermilk et al, 2013).

Breathing exercises are an effective, simple, non-invasive method to reduce labour pain that have no side effects (Dengsangluri, 2015). The reviewed article reported that using breathing control techniques with aromatherapy effectively reduced labour pain during the first stage. Healthcare providers can easily carry out this intervention; there is no need for complex support tools. However, the effectiveness of deep breathing interventions as a single intervention was not examined in the reviewed article. However, the combination of breathing techniques with other interventions can also be achieved simply.

Focus

Maryam's flower focus can be used to reduce labour pain during the first stage. A focal point is used if a mother wants to open her eyes during contractions (Reeder et al, 2018). Semple and Newburn (2011) revealed that focus techniques include self-hypnotic methods that can reduce pain during labour. As mothers in labour visualise their work, the parasympathetic system is activated to decrease tension (Türkmen et al, 2020). Pregnant women who use focused attention are more comfortable during the labour process (Gayeski et al, 2014).

Türkmen et al (2020) stated that focusing on Maryam flowers during labour was a safe and effective intervention to reduce labour pain. However, the success of this intervention depends on the mother's belief that the opening of the petals of Maryam flower coincides with the opening of labour. Maryam flowers are widely believed to be able to launch childbirth in Middle Eastern and Asian countries (Indonesian Ministry of Religion, 2011), meaning this intervention is likely to be more effective for the population of these countries. Based on this research, it can be concluded that focusing on Maryam flowers can effectively reduce the first stage of labour pain in primiparous mothers.

Virtual reality

Virtual reality stimulates the visual cortex and involves other senses, such as hearing, limiting processing of nociceptive/pain stimuli and helping to reduce labour pain (Tashjian et al, 2017). Nociceptive stimuli are when stimulation passes through small nerves and causes inhibitor neurons to become inactive, causing pain (Sato et al, 2010). Wong et al (2021) reported that virtual reality is an effective visual stimulation technique to reduce pain in the first stage of labour. However, this technique is expensive and requires specialist expertise from the provider. Although this intervention is effective, it is not suitable to be applied to areas without access to advanced technology because the tools used are sophisticated. However, for developed countries, this intervention would be suitable to reduce labour pain.

Clinical implications

Labour pain is commonly experienced by mothers during birth (Ricci et al, 2013). Severe pain during labour can lead to prolonged labour (Anita, 2017), postpartum depression (Tzeng et al, 2017), hypoxia and metabolic acidosis in infants (Liu and Wang, 2020). Providing comfort for mothers in labour is the role of maternity nurses and midwives when accompanying childbirth (Reeder et al, 2018). Based on the present literature review, several sensory stimulation interventions can be used to reduce labour pain during the first stage. Aromatherapy, music therapy or breathing techniques are accessible management alternatives to reduce first-stage labour pain (Simavli et al, 2014; Tanvisut et al, 2018; Vakilian et al, 2018). A mother admitted to the hospital in the early stages of labour with high confidence can be given an intervention based on focusing on Maryam's flowers (Türkmen et al, 2020). Hospitals with virtual reality facilities can use virtual reality to reduce first stage labour pain (Wong et al, 2021).

Conclusions

Interventions using sensory stimuli to reduce pain in the first stage of labour include aromatherapy, music therapy, breathing control, focusing and virtual reality. Each intervention has advantages and disadvantages, depending on the context of the mother and the hospital. Their use can be adapted to each health service's situation, conditions and facilities and can be used as single or combined interventions.

Further research should look at combinations of interventions and comparisons between interventions to determine which are most effective in aiding management of first stage of labour pain.

Key points

• Severe first stage labour pain can harm both mother and baby.
• Childbirth assistant nurses or midwives can provide non-pharmacological interventions in the management of labour pain.
• Assessment of patient preferences and beliefs is important in selecting effective labour pain interventions.
• Childbirth assistant nurses or midwives should help women manage labour pain by taking into account simple, effective sensory stimulation techniques.

CPD reflective questions

• How do the women in your practice perceive labour pain?
• What interventions might this imply would be effective in your practice?
• What facilities do you have that could be used to support management of labour pain using sensory stimulation interventions?
• What education is given during prenatal classes in dealing with labour pain in your practice?