Background
Labour pain may be the most severe pain that many women experience in their lifetime, and every woman has the right to choose a form of pain management during labour [
1]. With the development of anaesthesiology and the demand for pain relief in labour, labour neuraxial analgesia, e.g., epidural analgesia (EA) and combined spinal-epidural analgesia (CSEA), has become widely used in developed countries [
2]. A national survey among anaesthesiologists between 2003 and 2004 in China estimated that the national labour neuraxial analgesia rate was less than 1% [
3], much lower than the rates in developed countries. Actions by Ling-Qun Hu and his colleagues have played a positive role in popularizing labour analgesia in China [
4]. The National Health Commission issued two policies in August and November 2018 to promote labour neuraxial analgesia in China, which have been officially implemented in pilot hospitals since January 2019 [
5,
6]. The national policy mainly includes five main elements: improving the skills of labour analgesia, improving the scientific choice of delivery mode, enhancing the awareness of hospitals and relevant departments of labour analgesia, strengthening health education for pregnant women and their families, making full use of the demonstration and driving role of pilot hospitals. However, national reports on the trends of the labour neuraxial analgesia rate in China and the effect of the national policy are currently lacking.
The risk of adverse maternal and perinatal outcomes has played an important role in the promotion of labour neuraxial analgesia. A Cochrane systematic review reported that compared with non-epidural or no pain relief during labour, EA (including CSEA) had an increased risk of assisted vaginal birth, maternal hypotension, maternal fever and some other complications [
7]. Most studies focus on anaesthesia-related complications. However, there were no trials regarding rare but potentially severe adverse maternal (such as maternal near miss) or long-term neonatal outcomes [
7]. An observational study with large samples may help to explore the association. Because randomized controlled trials (RCTs) are often limited in terms of generalizability [
8], the evidence provided by real-world observational studies can complement the findings from RCTs [
9]. Previous studies on the association between labour neuraxial analgesia and adverse maternal and perinatal outcomes in China are mostly limited in single hospital with small sample sizes [
10,
11].
In our study, data from China’s National Maternal Near Miss Surveillance System (NMNMSS) were used to estimate the trends of labour neuraxial analgesia rates between 2012 and 2019, both at the national and provincial levels. We also estimated the effect of the national pilot policy launched in 2018 and identified the association between labour neuraxial analgesia and adverse maternal and perinatal outcomes in China. The primary outcomes were maternal near miss (MNM) and intrapartum stillbirths. The secondary outcomes included three main causes of postpartum haemorrhage (genital tract trauma, uterine atony, placental retention) and 1- and 5-min Apgar scores lower than 7. We used up to six types of propensity score analysis, as well as E-Value, to enhance the reliability of the results.
Discussion
Our study, for the first time, showed that the national labour neuraxial analgesia rates among women with vaginal delivery increased rapidly from 2012 to 2019 in China. Most provinces experienced the same rapid rise during this period. The national pilot policy played an important role in the promotion of the labour neuraxial analgesia in China. Compared to women without any analgesia, women with labour neuraxial analgesia were associated with more genital tract trauma and MNM in non-pilot hospitals, but not pilot hospitals.
Labour neuraxial analgesia has been practised and popularized worldwide since the twentieth century. However, wide variations in the use of EA have been reported, even in developed countries [
2]. The standardized promotion of labour neuraxial analgesia among a large number of women in a single hospital had only been available in China since 2001 [
31]. To slow the increase in CS rates and improve women’s health, Chinese obstetric experts have proposed popularizing labour neuraxial analgesia among vaginal deliveries in China [
32]. Several relevant actions have been taken [
4,
33]. Demand from society and actions from academia eventually led the government to launch a national policy to promote labour neuraxial analgesia in 913 pilot hospitals at the end of 2018 [
6]. Although the rate is obviously higher than in the past, there is still a large gap in labour neuraxial analgesia rates between China and developed countries.
The factors that influence the popularization of labour neuraxial analgesia are complex, such as education and parity [
32,
34‐
37]. Reimbursement for neuraxial analgesia may increase hospital income and thus serve as an incentive, but could lead to the overuse of labour analgesia in some hospitals [
2]. Nevertheless, there are some more important contributing factors to the low labour neuraxial analgesia rate in China: preference to have a CS during the “One-Child” period, unreasonable charging standards for labour analgesia among vaginal deliveries [
3], and shortage of anaesthesiologists (0.5, 2.5 and 2.8 anaesthesiologists per 10,000 population in China, the USA and the UK, respectively) [
33]. Although the number of anaesthesiologists at level 3 hospitals (especially general hospitals) is relatively large, the anaesthesiologists are more willing to participate in surgery than labour neuraxial analgesia [
3,
33].
However, the demand from society for vaginal delivery has changed since the implementation of the “Universal Two-Child” policy [
38]. The proportion of women who choose vaginal delivery during their first birth may increase to ensure that it is safe to give birth to their second child. Labour analgesia can relieve labour pain and further promote women’s willingness to choose vaginal delivery. After the national pilot policy, the labour neuraxial analgesia rate has been increasing more rapidly. Our research also shows that the effect of this policy began to appear even as early as September 2018. This time node is consistent with the government’s notice of strengthening and improving anaesthesia medical service, including popularizing labour analgesia [
5]. In addition, the national policy has clear spill over effects, as the labour neuraxial analgesia rate after the policy is also significantly faster than that before the policy in non-pilot hospitals. The National Health Commission’s purpose of setting up the pilot hospitals in the policy is to popularize the technology of labour analgesia on the basis of ensuring the safety of mothers and infants. These pilot hospitals are often those with sufficient anaesthesiologists, higher capability of obstetrical services and support from experienced multidisciplinary rescue teams [
6]. In the NMNMSS, there are great differences in hospital-level distribution between non-pilot and pilot hospitals. The proportion of level 3 hospitals in pilot hospitals is much higher than that in non-pilot hospitals. The labour neuraxial analgesia rate in non-pilot hospitals has also risen rapidly, which may be due to the demand of economic interests and blindly following the national policy. It may bring challenges to the safety of mothers and infants.
Systematic reviews and clinical guidelines for labour neuraxial analgesia have identified some advantages and disadvantages [
7,
34,
39]. However, some areas, such as the risk of postpartum obstetric complications, MNM, and even maternal death, remain uncertain [
7,
39]. Our study suggests that labour neuraxial analgesia may be associated with increased risk for genital tract trauma and MNM. The consistency of the results from traditional covariates models and several approaches of PS analysis prove the robustness and reliability of the findings. In China, pregnant women usually talk to their anaesthesiologist and obstetrician when they reach 36–38 weeks gestation to see whether vaginal trial of labour and labour analgesia is needed. Very few women decide on the need for labour analgesia until close to the onset of labour. Women who receive labour neuraxial analgesia are subject to strict screening for indications and contraindications (such as abnormal coagulation) [
40]. Our analysis on the association between labour neuraxial analgesia and adverse maternal and perinatal outcomes has excluded women with any antepartum complications or medical diseases to eliminate the interference of diseases that existed before labour neuraxial analgesia. In addition, analysis of E-Value enhances the robustness of these findings, as it is almost impossible to have such a strong potential unobserved confounding factor in addition to the confounding factors that have been adjusted by the model. Therefore, our findings are highly meaningful for clinical practice.
Previous studies reported that no significant relationship between epidural usage and genital tract trauma [
41‐
43]. Timothy et al. even reported that epidural was negatively associated with laceration [
44]. Compared with our study (the sample size is more than 4 million), the sample size of these previous studies was very small, the lowest is only about 200 [
43] and the highest is less than 6000 [
42]. In addition, Timothy et al.’s study included operative vaginal delivery as a mediator in the regression model [
44], possibly resulting in over-adjustment [
45], and failing to correctly estimate the total effect of epidural analgesia. Changes in obstetric management could mediate the associations found in the current study.
A secondary analysis of the WHO Multicountry Survey, from another perspective, reported that women with severe maternal morbidity (SMM) were associated with a higher use of labour analgesia than those who did not experience SMM [
46]. We also confirm our previous concerns about adverse effects caused by policy spill over: labour neuraxial analgesia increased the risk of genital tract trauma and MNM only in non-pilot hospitals. All these findings suggest that promoting labour neuraxial analgesia requires care and caution.
To ensure the safety of the mothers who will choose labour neuraxial analgesia in the future, we have the following suggestions. First, labour neuraxial analgesia should be used upon request rather than routinely [
47‐
49]. Labour neuraxial analgesia may increase some risks, after all, it is a kind of human medical intervention. Reducing over-intervention in childbirth and providing maternity-centred services to ensure maternal safety during childbirth is the consensus of experts [
2]. Second, hospitals without enough anaesthesiologists or comprehensive rescue capacity should not be allowed to provide labour neuraxial analgesia services [
31,
50]. We do not warn against the use of labour neuraxial analgesia during vaginal delivery. We believe the health risk from labour neuraxial analgesia is controllable. However, it is difficult for level 1 hospitals and even some level 2 hospitals to provide adequate medical resources (anaesthesiologists, midwives and blood sources) to ensure safety. There are hidden risks in technique details of labour neuraxial analgesia. That is why we do not recommend blindly following the promotion of labour neuraxial analgesia in hospitals without adequate safety guarantees. Thus, most level 1 and level 2 hospitals that lack resources should focus more on non-pharmacological interventions (such as doula care or immersion in water) in the future. Third, there is an urgent need for formal clinical guidelines on labour analgesia. The Chinese Anaesthesiology Association published the “Expert Consensus on Labour Analgesia” in 2016 to guide clinical practice but did not provide details on the pros and cons of labour analgesia [
40]. Referring to guidelines from other countries, such as American College of Obstetricians and Gynecologists [
34], the formal guidelines in China should provide detailed specifications on how anaesthesiologists monitor maternal vital signs for labour neuraxial analgesia, including how to collaborate with other health care team members. Considering that severe postpartum haemorrhage is the main manifestation of MNM with labour neuraxial analgesia, the interventions for postpartum haemorrhage need to be included in the guidelines. Trainings at all levels for labour analgesia, especially for emergency handling of sudden problems, are also very important.
There are also several limitations in this study. First, due to the lack of labour information, women who laboured, intending vaginal delivery, but ultimately required delivery by emergency CS were excluded. Therefore, the findings of this study are only applicable to women whose final delivery method is vaginal delivery. Second, since the women who had intrapartum caesarean section were excluded, this study cannot assess the benefit of labour neuraxial analgesia from avoiding general anaesthesia when rapid conversion from epidural analgesia to anaesthesia is needed in an emergency. Third, as this study was an observational study, it can only suggested the association between labour neuraxial analgesia and adverse outcomes. In addition, due to the limited information that can be collected in the NMNMSS, our study is unable to further explore the biologic plausibility of labour neuraxial analgesia being directly related to postpartum haemorrhage. However, the findings of this study will provide direction for the next step in the design of more powerful causal arguments research.
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