INTRODUCTION

The labour process varies from woman to woman and its progress does not necessarily have to be linear in all cases. In most nulliparous women the dilation phase is completed in 18 hours and in the case of multiparous women it takes an average of 12 hours ⁽¹⁾, all this time passes with painful perineal and lumbar sensations that are generally more intense in primiparous women than in multiparous women^(2,3).

Pain during childbirth is described as one of the most intense pains a woman can experience in her lifetime. Currently, pain management is not only of interest from the point of view of symptomatic relief, but also because of the physiological changes it produces in the mother and foetus^(3,4,5,6,7). Authors such as Mallen Pérez et al.⁽⁸⁾ and Cobo Borda et al. ⁽¹⁾ report how childbirth was considered a natural event and was handled by primitive societies in a totally instinctive and solitary manner ^(1,8), while in some religions it was considered a punishment⁽¹⁾. The concept of pain in childbirth was modified and considered an emotion during periods such as the Middle Ages, the Renaissance and the Industrial Revolution^(1,9). Controlling pain in labour brings with it an increase in the physical and emotional well-being of the pregnant woman, which is why in the mid-19th century work began on the concept of pain during childbirth, in which medical care began to be provided and pharmacological analgesia was introduced, from ether and chloroform to the appearance of epidural analgesia⁽⁸⁾.

Each woman's expression of pain must be respected, and therefore it is necessary to personalise the resources available for pain relief and pain management during labour. These resources can be pharmacological or non-pharmacological, the latter of which can be divided into relaxation methods, psychological techniques and mechanical techniques. The use of non-pharmacological analgesic methods that are safer for both mother and foetus can be an alternative to pharmacological analgesic methods that may carry various risks, as in the case of epidural analgesia^(4,6,10,11). In particular, non-pharmacological analgesic methods such as relaxation techniques, among which we find: warm water immersion, massage and reflexology, acupuncture and acupressure, music therapy, aromatherapy, continuous support or mind-body practices that include yoga, meditation, visualisation and breathing techniques, among others. We could also make use of psychological techniques such as hypnosis or mechanical techniques such as transcutaneous electrical nerve stimulation, use of a birthing ball or Swiss ball, thermal therapies and intradermal injection of sterile water^(4,12).

Currently, according to various studies, pregnant women are provided with more information on pharmacological methods of pain relief (especially epidural analgesia) than on the various alternative non-pharmacological methods. Some studies conclude that it would be advisable for professionals to continue searching for the most suiTable way to care for each woman according to her preferences in order to adapt to each situation that arises and to offer all the existing analgesic options, both pharmacological and non-pharmacological^{(6,10,11,12,13,14)}.

Because pain management during labour is a fundamental task that health professionals must address with the highest possible quality and, on the other hand, because pain in the labour process can cause alterations in the pulmonary and cardiovascular systems, considerably reducing tolerance to labour, there is a need to offer analgesia strategies that encourage and promote the participation of women in decision-making at the time of labour. Relaxation techniques could be a complementary and/or alternative non-pharmacological analgesic method in labour^{(6,7,11,12,13,14,15,16,17)}.

MATERIALS AND METHODS

RESULTS

In the initial search strategy, a total of 72 studies were identified, which were successively screened according to the purpose of the present study until the selection of studies was reached (Figure 1). Finally, 11 studies were included in this review, 6 of which are systematic reviews and 5 are randomised clinical trials.

Figure 1: Flow chart of the study. 

Flow chart of the study: The results obtained from the main search strings used in databases are presented in (Appendix C).

The results obtained from the included studies are described below. First, the most relevant characteristics of the included studies are presented (Table 1). Finally, the main results on relaxation techniques as a non-pharmacological analgesic method used during labour are discussed.

Table 1: Characteristics of the studies included. 

The results of this review presented in the Table above aim to achieve the objective proposed for this work. All the selected studies, regardless of their design, study patients belonging to the same population group, in this case women during pregnancy and childbirth. To analyse the obstetric effects of relaxation techniques in the treatment of pain during labour, 11 articles were analysed, including the study by Allameh et al. ⁽²²⁾ in which a comparative study was carried out between pregnant women treated with acupuncture and pregnant women treated with pethidine and their relationship with pain during labour. With regard to the same variable, in this case pain control, Roque Mafetoni et al. ⁽²⁴⁾ worked with acupressure at the time of delivery and found positive results. Genç Koyucu et al. ⁽²⁵⁾, in their study, presents the ability to reduce pain with an intradermal injection of sterile water, which is also useful because it does not limit maternal mobility or interfere with the progress of labour or the ability to push. In any case, the literature indicates that immersion in water is the non-pharmacological treatment of choice, as highlighted by Czech et al. Cluett et al. ⁽²⁹⁾, refer in their work on the same subject.

Another relevant study was that of Levett et al. ⁽²³⁾ where they claim to reorient prenatal education and promote childbirth as a normal physiological event. Madden et al. ⁽²⁷⁾, work on the effectiveness of hypnosis at the time of delivery, corroborating the reduction of analgesia used in cases treated with this therapy.

Smith et al. ⁽³⁰⁾ examine massage therapies, reflexology and other manual methods for the treatment of pain during labour. In addition, they examine the effects of mind-body relaxation techniques for pain management during labour on maternal and neonatal well-being during and after birth ⁽³¹⁾.

DISCUSSION

The eleven studies included in this systematic review suggest very limited ascientific evidence on relaxation techniques during labour. Due to the small number of studies examining different methods of non-pharmacological analgesia during labour, there is a limitation in making comparisons with other studies. This is highlighted in his latest study on the subject Yinchu et al. ⁽³²⁾, where he stresses the need for more well-designed projects to validate the conclusions of his work.

It is true that this study attempts to investigate the most recent scientific evidence and, if possible, the highest methodological quality by using limits in the search chains and through a critical reading of the selected studies. The heterogeneity of the results is also accepted, mainly due to the specific objectives of examining and learning about the different non-pharmacological analgesia methods used, be they relaxation techniques, comfort measures and/or ways to control pain during labour.

During the process of preparing the study we tried to minimise the risk of bias and although the search for studies was exhaustive, accurate and in widely used languages such as English or Spanish, it is possible that some of the literature on relaxation techniques is not published in journals and therefore excluded from the main databases, so we cannot rule out the possibility that studies of interest may have been missed.

CONCLUSIONS

The main findings of this review include several areas that should be highlighted.

Firstly, the clinical implications of the subject matter of this review indicate that the results of the included studies on relaxation techniques during labour show a possible decrease in labour pain compared to usual care. In turn, there are results of moderate methodological quality showing a decrease in pain in the early stages of labour in those women in whom certain relaxation techniques were performed.

Even so, no study has found negative effects on the health of women and their babies, so it would be of interest to promote this type of therapy and study its follow-up.

In terms of research, it would be desirable for future research to follow the same line of investigation through the development of RCTs, due to the small number of studies present in the databases that analyse the different methods of non-pharmacological analgesia during childbirth. This aspect is recognised by all the authors included in this review.

With regard to the management of this type of therapy, it would be advisable for health professionals attending childbirth to receive ongoing training on the different pharmacological and non-pharmacological methods of analgesia, in order to develop analgesic strategies that encourage and favour the participation of women in decision-making at the time of delivery. This work should be backed and supported by appropriate health and educational policies.

The current scenario in which these therapies are being developed is still far from complete. This review concludes that the approach to childbirth treated with this type of therapy favours the woman and the baby, although a more thorough and detailed study is needed to understand the scope of these therapies in greater depth. At the same time, specific training for health professionals on this subject is crucial for the evolution of this type of treatment.