Episiotomy Practice and Its Associated Factors in Africa: A Systematic Review and Meta-Analysis

Background Episiotomy, a surgical procedure that enlarges the vaginal opening during childbirth, was common practice until the early 2000s. Other sources, including the World Health Organization (WHO), advocate for the selective use of episiotomy. Episiotomy rates, on the other hand, have remained high in developing countries, while declining in developed countries. As a result, the current study sought to determine the overall prevalence of episiotomy in Africa as well as the risk factors associated with its practice. Methods Articles were searched in international electronic databases. A standardized Microsoft Excel spreadsheet and STATA software version 14 were used for data extraction and analysis, respectively. The Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) checklist was used to write this report. A random-effects meta-analysis model was used to determine the pooled prevalence of episiotomy. A heterogeneity test was conducted using I-Squared (I2) statistics. Egger's test and funnel plots were conducted to detect publication bias. Subgroup analysis was also conducted. Association was expressed through a pooled odds ratio (OR) with a 95% Confidence Interval (CI). Result A total of 21 studies with 40,831 participants were included in the systematic review and meta-analysis. The pooled prevalence of episiotomy practice was 41.7% [95% CI (36.0–47.4), I2 = 99.3%, P < 0.001). Primiparity [OR: 6.796 (95% CI (4.862–9.498)), P < 0.001, I2: 95.1%], medical doctors- assisted delivery [OR: 3.675 (95% CI (2.034–6.640)), P < 0.001, I2: 72.6%], prolonged second stage of labor [OR: 5.539 (95% CI (4.252–7.199)), P < 0.001, I2: 0.0%], using oxytocin [OR: 4.207 (95% CI (3.100–5.709)), P < 0.001, I2: 0.0%], instrument -assisted vaginal delivery [OR: 5.578 (95% CI (4.285–7.260)), P < 0.001, I2: 65.1%], and macrosomia [OR: 5.32 (95% CI (2.738–10.339)), P < 0.001, I2: 95.1%] were factors associated with episiotomy practice. Conclusion In this review, the prevalence of episiotomy among African parturients was high. A selective episiotomy practice should be implemented to reduce the high episiotomy rates. Systematic Review Registration https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021293382, identifier: CRD42021293382.


BACKGROUND
An episiotomy is a vaginal and perineal surgical incision performed by a skilled birth attendant, to widen the vaginal opening (1,2), late in the second stage when the perineum is stretched thin (3), and it is one of the most commonly performed surgical procedures all over the world (4). There are seven different ways to perform an episiotomy, with the two most common types in the literature and medical practice being "midline" and "mediolateral." A midline (sometimes called "median") episiotomy is a vertical incision from the posterior fourchette that runs along the midline through the central tendon of the perineal body. A mediolateral episiotomy is an incision beginning in the midline and directed laterally and downwards away from the rectum (2).
This surgical procedure is not without consequences as compared to permitting the perineum to tear. To begin with, episiotomy might be detrimental with respect to urinary incontinence symptoms (5). In a study conducted to assess the impact of episiotomy on the urogenital hiatus using transperineal ultrasound, the urogenital hiatal area was altered by episiotomy (6). In contrary, indicated use of episiotomy resulted in a significant decrease in third and fourth degree lacerations in a population-based observational study in Texas, United States of America (7).
According to a Cochrane database systematic review, women who had selective episiotomy experienced 30% less severe perineal trauma at birth than women who had a routine episiotomy policy. In terms of Apgar scores of <7 at 5 min, the number of women developing perineal infection, the number of women reporting painful sexual intercourse 6 months or more after delivery, and urinary incontinence 6 months or more after delivery, there was probably no or little difference reported. However, other significant long-term effects and outcomes were not reported in these trials (urinary fistula, rectal fistula, and fecal incontinence). As a result, the rationale for performing routine episiotomies to prevent severe perineal trauma was found to be unjustified, and there were no benefits to the baby or the mother from routine episiotomy (8).
Even when episiotomy technique is considered, mediolateral episiotomy does not appear to be protective against clinically or sonographically diagnosed obstetrical anal sphincter injuries (OASIS), and it was associated with decreased sexual functioning as well as sexual desire, arousal, and orgasm within the first 5 years after delivery (9). Furthermore, in a study conducted in 2015-2016 with the goal of describing the detailed epidemiology of labor and delivery in China, mediolateral episiotomy without indications more than doubled the risk of third and fourth degree perineal laceration in nulliparae without neonatal benefits, remembering the consequences of injudicious use of episiotomy (10). Prophylactic use of episiotomy in critical conditions such as shoulder dystocia, instrumental deliveries, occiputposterior position, fetal macrosomia and non-reassuring fetal heart patterns don't prevent 3rd or 4th degree perineal tear (11). Nonetheless, a comparative, retrospective, mono-centric study in a university maternity unit in Besançon, France, found that selective episiotomy could reduce the incidence of perineal tears, particularly second-degree perineal tears, without increasing the rate of OASIS (12).
In order to combat the pain correlated with episiotomy, water birth has gained popularity globally, especially in midwifery-led care settings (13). Women's experiences with water birth matched groups in a prospective study by Lathrop et al. revealed that water birth was associated with a decreased likelihood of perineal lacerations (14). Furthermore, water immersion may reduce episiotomy rates (15,16). Nonetheless, a lack of high-quality evidence clouded informed decisions about the advantages and disadvantages of water birth (17). Therefore, the merit and risks of water birth should be discussed thoroughly with the parturient during the process of informed decision making with mothers interested in this option (16).
Every year, ∼140 million babies are born worldwide (18). In 2019, the United Nations (UN) estimated that the total fertility rate of Sub-Saharan Africa (SSA) would be at 4.7 births per woman from 2015 to 2020, which is more than double the level of any other region in the world (19). In concert with this, the rates of episiotomy practice have remained high worldwide, particularly in less industrialized countries and East Asia (20)(21)(22).
Furthermore, despite the standard recommendations that corroborate judicious use of episiotomy, increasing and variable patterns have been reported in Mexico: 41.8% in the state of Oaxaca and 77.2% in Mexico City (8,25,31 (35). To summarize, the larger disparity in episiotomy rates around the world, as made evident by historical trends, is closely attributable to differences in episiotomy policies and resources (8,20).
Individual and clinical factors related to mothers; individual and clinical factors related to the newborn; as well as the socio-demographic profiles of the parturient in Africa and other countries influence episiotomy practice (36). In studies conducted in Brazil (37,38), Nigeria (39)(40)(41)(42),Turkey (43), the United States (44), and Ethiopia (45,46), the odds of episiotomy practice were positively correlated with younger age at delivery. Nonetheless, advanced maternal age (≥35) was reported as an attributable factor in some studies (37,(47)(48)(49).
Banta and his associate found four advantages to episiotomy. To begin with, it is claimed that a clean, straight incision is easier to repair and heals faster than a laceration or tear. Second, it is claimed that episiotomy results in fewer third-degree lacerations. Third, episiotomy is said to prevent fetal brain injury by lowering the fetal head's pressure on the pelvic floor. Fourth, episiotomy is said to shorten the second stage of labor, which helps to avoid pelvic floor damage (71). Additionally, episiotomy is justified in preeclampsia (72), in the event of abnormal cardiotocography, inability to control maternal blood pressure, imminent eclampsia, worsening biochemistry, or worsening maternal symptoms, for expeditious delivery of the newborn by shortening the second stage of labor and avoiding suffering for the baby (73). Finally, episiotomy requires laboring mothers to provide informed consent (74). Performing episiotomy without informed consent or with coerced consent is deemed to be instances of obstetric violence (16).
In Africa, although there has been no representative data, the reported rate of episiotomy ranged from 9.3% in a study conducted in South East Nigeria (40) to 73% in Uganda (55). Understanding the magnitude and risks associated with episiotomy can help adhere to existing or develop new protocols that are consistent with World Health Organization (WHO) (75) and American College of Obstetricians and Gynecologists (ACOG) recommendations that emphasize the judicious use of episiotomy (3). To date, there has been no systematic review and meta-analysis conducted to estimate the pooled prevalence and identify risk factors associated with episiotomy practice in Africa. Therefore, the current study aimed to address these two questions: (i) what is the continent's overall estimate of episiotomy practices? (ii) What are the factors that may influence episiotomy practices among African women who give birth in health facilities?

Reporting and Study Protocol Registration
The goal of this systematic review and meta-analysis was to determine the pooled prevalence of episiotomy practice and the factors associated with it among African parturients who gave birth in public health facilities. The study protocol for this study was prepared and registered in the International Prospective Register of Systematic Reviews (PROSPERO) databases on 25/12/2021 (available from: https://www.crd.york. ac.uk/prospero/display_record.php?ID=CRD42021293382) we confirmed the absence of ongoing systematic reviews on this topic by following the guidance note for registering a Systematic Review Protocol to avoid duplication. The metaanalysis was reported using the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA)-Statement (76) (Supplementary File 1).

Inclusion Criteria
The inclusion criteria for this review were determined using the CoCoPop mnemonic (condition, context, and population). Population/Participants -parturient mothers who were reported to have undergone episiotomy at health facilities in Africa. Context-Observational Studies (descriptive and analytic crosssectional studies, cohort studies, and case control studies) published in English between January 1, 2000 and December 31, 2021, spanning more than two decades due to a scarcity of primary studies. Condition-Studies that reported the outcome of interest based on the prevalence and risk factors associated with episiotomy practice were included in this review.

Exclusion Criteria
We excluded studies without full text access; articles that contained insufficient information; findings from personal opinions; articles reported outside the scope of the outcome of interest; qualitative study design; case reports; case series; letters; and previous systematic review.

Operational Definitions
Episiotomy It is an obstetric surgical procedure in which incisions are made in the vulva and perineum to allow for a smooth delivery of the newborn by creating enough space (3).

Delayed or Prolonged Second Stage of Labor
If the labor lasts longer than 2 h without epidural analgesia or 3 h with epidural analgesia in nulliparous women, or 1 h without or 2 h with epidural analgesia in multiparous women (77).

Macrosomia
A new born birth weight ≥4,000 g (78). Oxytocin Is a drug prescribed for laboring mothers for induction or augmentation of labor by enhancing uterine contraction (78).

Parity
Parity is determined by the number of pregnancies reaching the age of viability. A woman who has been delivered only once of a fetus or fetuses born alive or dead with an estimated length of gestation of above the age of viability is termed primiparity. Whereas, multipara is a woman who has completed two or more pregnancies to the age of viability (78).

Spontaneous Vertex Delivery
When the fetal presenting part is the vertex or occiput in a laboring mother, labor begins spontaneously and the delivery is accomplished with minimal assistance (78).

Search Strategy
Our search was restricted to articles published in English from January 1, 2000 to December 31, 2021. The electronic databases of PubMed, Hinari, Science Direct, Web of Science, African Journal of Online (AJOL), Cumulative Index to Nursing and Allied Health Literature (CINAHL), Excerpta Medica database (EMBASE), Google, Journal Storage (JSTOR), and Google scholar were searched. Using the snowballing method, the reference lists of the identified studies were also scrutinized to identify other relevant articles that were not captured during the initial search. We used key concepts to build a search strategy while conducting a comprehensive PubMed search. Initially, Medical Subject Headings (MeSH) terms relevant to our search were identified and added to the search builder. Next, we identified every possible keyword for each key concept and thoroughly used a combination of MeSH and keywords, truncating ( * ) of stems that are four letters or longer, putting double quotes ("") around any multi-phrase, and adding field tags [tiab] and [tw] for each concept. Finally, after double checking that syntax was correct and Boolean operators were in all caps, we started running a search in the PubMed search box using a building block approach, which means we built the search one concept at a time and then combined concepts together at the end ["women * " (text word) OR "pregnant mother" (text word) OR "birth" (text word) OR ("pregnant women" (MeSH Terms) AND "women" (MeSH Terms)] AND ["episiotomy" (text word) OR "episiotomy practice" (text word) OR ("obstetric surgical procedures" MeSH Terms)] AND "episiotomy." From January 1st to February 30th, 2022, two authors (BW and EA) participated in a double blinded search. The full search results were included as an additional file (Supplementary File 2).

The Study Selection Procedure
The retrieved studies were exported to EndNote X7, which was then used to remove duplicate studies. After removal of duplicates, two authors (BW and MO) independently screened the titles and abstracts to determine the eligibility of studies. To describe the extent to which assessments by multiple authors are similar, the Cochrane handbook for systematic reviews of interventions was consulted. Values of kappa 0.75 (75 percent) were considered in this way, indicating excellent agreement. The screened articles were then subjected to a full article review by two independent authors (TI and HB). The inclusion and exclusion criteria were used to screen the articles.

Methodological Quality Assessment
The Joana Briggs Institute (JBI) critical appraisal checklists (79) were used to assess the quality of the studies. The methodological quality of each study was independently evaluated by two reviewers (EA and LT). Discrepancies were solved through discussion with a third independent reviewer (MS.O.). Hence, studies scoring 7 or above after evaluation against these criteria were included in this systematic review and meta-analysis. In this manner, for studies reporting only prevalence data, the following major components were evaluated: appropriateness of the sample frame for addressing the target population, sample size adequacy, study setting and participants, whether the data analysis was conducted with sufficient coverage of the identified sample, validity and reliability of the measurement, appropriateness of the statistical analysis, and adequacy and management of response rate (Supplementary File 3). For the analytical crosssectional studies, the JBI checklist assessed the following main components: inclusion criteria, participants and settings, whether the exposure was measured in a valid and reliable way, whether the standard and objective criteria were used for measuring the outcome, confounding factors and strategies used to deal with them, whether the outcome was measured in a valid and  reliable manner, and appropriateness of the statistical analysis (Supplementary File 4).

Data Extraction
Using a standard Microsoft Excel spreadsheet, BW and MO independently extracted the relevant data. For data extraction, the JBI adopted formats were used (80). The author's name, study period and year of publication, methods and settings, age of the mothers, sample size and sampling procedure, data collection instrument, estimate of episiotomy practice with 95 percent confidence interval, response rate, and factors associated with episiotomy were all extracted. After retrieving data from 30% of the studies, the reliability agreement among the data extractors was assessed and confirmed using Cohan's kappa coefficient. and a kappa statistic value ≥0.5 was considered congruent and accepted. In the case of disagreements between the two data extractors, LT was involved in resolving them through discussion and re-checking of the original articles.

Summary Measures
The number of parturients who received episiotomy was divided by the total number of parturients and multiplied by one hundred to calculate the pooled episiotomy practice among African parturients. The pooled effect was investigated using the OR. Furthermore, variables identified as a risk factor for episiotomy in at least three studies were taken into account.

Publication Bias and Heterogeneity
To check for publication bias, we used Egger's statistical tests and funnel plots. The presence of publication bias was thus declared with a statistical significance of 5%. The I 2 -test was also used to determine heterogeneity. When the I 2 -test value was 25, 50, and 75%, heterogeneity was classified as mild, moderate, and high, respectively, across the studies.

Statistical Methods and Analysis
All the extracted data was exported to STATA version 14 software for analysis. Due to the high heterogeneity among the included studies, the random-effects model was used for analysis. To find the source of heterogeneity, we used subgroup analysis based on African regions and meta-regression based on year of publication and sample size. The impact of the retrieved associated factors on the outcome variable was also investigated. Texts, forest plots, and tables were used to illustrate the findings of this systematic review and meta-analysis. The characteristics of the included studies were described using the OR with a 95% CI.

RESULT Study Search and Selection
Our search was restricted to articles published in English between January 1, 2000 and December 31, 2021 in the electronic databases PubMed, Hinari, Science Direct, Web of Science, CINAHL, and EMBASE. In addition, Google, Google scholar, and AJOL were used. Through systematic and manual searching, 934 primary articles were found. Due to duplication, 770 articles were removed. The remaining 164 were screened based on their title and abstract, with 130 being eliminated as unrelated to our study. Finally, 34 full-text primary articles were evaluated against eligibility criteria, and 21 were selected for quantitative analysis (Figure 1).

Study Characteristics
This systematic review and meta-analysis included a total of 21 articles from seven African countries. Eighteen primary studies employed an analytical cross-sectional study design, while the remaining three studies employed a descriptive cross-sectional study design. Regarding Table 1).

Prevalence of Episiotomy Practice
This systematic review and meta-analysis included 21 studies to estimate the pooled prevalence of episiotomy practice among African parturients who gave birth in health facilities. The heterogeneity (I 2 ) of the included studies was (I 2 = 99.3%; P < 0.001) when using the fixed effect model. Due to the high heterogeneity of the data, we used a random effects model to estimate the pooled prevalence of episiotomy practice, which was 41.7% [95% CI (36.0-47.4)] (Figure 2).

Heterogeneity
We used subgroup analysis based on African regions, as well as meta-regression based on year of publication and sample size, to find the source of heterogeneity.

Subgroup Analysis by Region
As shown in Figure 5, a significant variation in episiotomy practice can be seen across the three regions in Africa. Episiotomy was most performed in central Africa (40-42, 56, 58, 63, 65, 82, 84, 85) of parturients. Of the 21 included studies, 10 studies were reprorted from East African countries, while ten studies and one study were reported from westAfrican, and central African countries respectively.

Meta Regression
Based on sample size and publication year, we used randomeffects meta regression to find the source of heterogeneity at a 5% significance level. As shown in Table 2, these covariates were not found to be the source of heterogeneity.

Sensitivity Analysis
We used the random-effects model to perform sensitivity analysis to determine the impact of a single study on the overall metaanalysis. The results of the analysis revealed that single study estimates are closer to the combined estimate, implying that a single study has no effect on the final pooled prevalence of episiotomy practice ( Table 3).

Factors Associated With Episiotomy Practice in Africa
The pooled odds ratio was used to identify factors linked to episiotomy practice, and the association with the outcome variable was declared at a 5% significant level. As a result, eight variables were extracted from at least three studies. Six variables were found to be predictors of episiotomy performance: birth attendant, mode of delivery, oxytocin use, prolonged second stage of labor, birth weight, and parity.

DISCUSSION
The aim of this meta-analysis was to find out how common episiotomy was and what factors were linked to it. This review included twenty-one studies in order to summarize the extent of episiotomy use and identify associated factors among African women who gave birth in public health facilities. These results   have been obtained from research conducted in a number of African countries. The routine use of episiotomy, according to researchers, increases the risk of perineal trauma (27). All international organizations, including the WHO, agree with the body of evidence that routine episiotomy has no place in the modern era of advanced maternal care (75). Furthermore, the 2006 ACOG bulletin did not recommend the routine use of episiotomy (3). Nonetheless, a remarkable spectrum of episiotomy practice has been observed among countries around the globe (82). The current review found that the pooled prevalence of episiotomy practices among laboring mothers in Africa was 41.7 [95% CI (36.0-47.4)] for all vaginal deliveries. There is a wide difference in episiotomy practice from region to region within the African continent. The sample size, year of publication, and settings where the studies were conducted might have contributed to a high and uneven spectrum of episiotomy. Furthermore, such disparities may indicate a lack of evidence-based standardized policy, training, and practice across the continent. Another possible explanation for the variation in episiotomy practices among African countries could be the preference to employ episiotomy frequently because of the simultaneous belief that allowing even minor perineal tears is more cumbersome than repair when an episiotomy cut is performed.
This systematic review and meta-analysis also identified potential determinants of episiotomy practices among parturients in Afrika. Thus, primiparity was found to be significantly associated with the use of episiotomy, which is supported by the findings of other previous studies (30,68). Another study also found that primiparas were more likely to undergo episiotomy than multiparas (28). The results of this review are also in line with those of previous studies conducted in Ethiopia (45,46,53,57,61,64), Nigeria (40-42, 56, 58, 63, 65), Brazil (92), Vietnam (93), Iran (67), Saudi Arabia (94), Latin America (59), France (68), East African migrants in Australia (95), Taiwan (96), and Vietnam born women in Australia (30). The potential explanation may be that episiotomies are thought to speed up the second stage of labor and reduce the risk of spontaneous perineal tears, but such perceptions among obstetricians or midwives have not been supported by evidence. Fetal macrosomia is common in obstetrics with problems in both the mother and newborn. The current review also showed that newborn birth weight ≥4,000 g was another risk factor associated with the practice of episiotomy compared with normal birth weight, which coincides with the findings reported in studies carried out in Ethiopia (53,54,57), France (51), and Nigeria (42,56,82). Other than newborns' , fetal macrosomia causes maternal complications during delivery, such as 3rd or 4th degree perineal tears (97,98). Rates of episiotomy, and other morbidities and mortality associated with predicted macrosomia could be reduced by cesarean deliveries (99). However, when such prenatal screening is not available as in underdeveloped countries, it contributes to high magnitudes of episiotomy.
Statistical analysis of this result also indicates that a protracted second stage of labor is among the important risk factors positively associated with episiotomy. This finding is also supported by studies conducted in Iran (67), Spain (100), and Brazil (92). When mothers exert themselves in labor for more than 2 h, they usually become exhausted. Moreover, inadequate provision of maternal support will also result in prolonged labor. This time, the attending healthcare professional is forced to perform an episiotomy cut to alleviate or reduce morbidity to the fetus (53).
In present study, laboring mothers who had used oxytocin for the induction or augmentation of labor had higher odds of being exposed to episiotomy than their counterparts. Our results concur with the findings in Iran (67), Brazil (92), Vietnam (30), and Latin America (32). Similarly this review is congruent with a study conducted in Shroud City, northeast Iran (67). The potential explanation could be due to oxytocin induced uterine hyper stimulation which in turn which may affect the normal beat to beat variability during labor resulting in non-reassuring fetal heart rate patterns. In such cases episiotomy is usually performed for expeditious delivery of the baby in an attempt to shorten labor time.
None spontaneous vertex deliveries (vacuum-assisted, forceps, and assisted breech deliveries) were another risk factor for episiotomy practice in laboring mothers compared with spontaneous vertex delivery and it is in line with previous studies conducted in other settings (32,37,67,94). Such a correlation may arise from tertiary hospitals' endeavors to handle abnormal labor, complex and advanced maternity care. Therefore, doctors and midwives may perform an episiotomy to decrease perineal tears in such a situation.
The other finding from this study is that deliveries attended by doctors were positively associated with episiotomy practice compared with deliveries attended by midwives. Similar findings have been observed in other settings (40,57,61). One of the reasons might be that abnormal labors are frequently attended by medical doctors and, hence, episiotomies are performed liberally to support and assist the labor process with forceps or vacuum delivery.

Limitations of This Study
The limitations of this systematic review have been acknowledged. Some studies did not contain sufficient predictor variables to adequately determine the degree of prediction. However, attempts were made to include all other potential variables across the identified databases. Furthermore, in this review, the study method used in all included articles was a cross-sectional design. As a result, the outcome variable might be affected by other confounding variables, which would decrease the power of the study and the causal conclusion between episiotomy and its associated factors. In the current metaanalysis, all included studies were conducted in African countries in three regions: Eastern Africa, Central Africa, and Western Africa. Therefore, it might lack continental representativeness because no information was found in the northern and southern regions of the African continent. However, the maternal health care and health care facilities in these regions are not different from those in other regions of the continent. Furthermore, the results of this review should be interpreted cautiously as there is significant heterogeneity in pooled effect estimates.

Strength of This Study
The protocol for this study has been registered. More than seven online databases were searched to avoid missing published studies, including articles published in African journals. In addition, a manual search was performed to retrieve the article using Google Scholar. During the selection of articles, the PRISMA guidelines were strictly followed, and the articles were closely assessed for their quality using the newly amended JBI critical appraisal tool. Furthermore, we used broader inclusion criteria to include articles published from 2000 to 2021GC. In studies that reported percent of episiotomy in both primiparous and multiparous parturients, additional analysis was performed. A sensitivity analysis was also carried out.

CONCLUSION
The pooled random effect meta-analysis revealed that the prevalence of episiotomy practice among laboring mothers in Africa was high when compared to existing global recommendations, including those from the WHO. Furthermore, primiparity, macrosomia, prolonged second stage of labor, instrument assisted vaginal deliveries, augmented or induced labor using oxytocin, and deliveries attended by medical doctors were independent predictors of episiotomy practice in African health facilities.

RECOMMENDATIONS
As a result, we recommend that African countries adopt a restrictive episiotomy policy to lower their rates and limit morbidity associated with injudicious episiotomy practice. To reduce the risks associated with macrosomia, prenatal screening with obstetric ultrasound and cesarean section delivery should be encouraged. Countries should either follow international guidelines like WHO and ACOG recommendations or create their own protocols. To change current beliefs about episiotomy in primiparous women, more in-service training for midwives and obstetricians is required. Episiotomy should only be performed when there is a clear indication or when evidence supports it.

DATA AVAILABILITY STATEMENT
The original contributions presented in the study are included in the article/Supplementary Material, further inquiries can be directed to the corresponding author.

AUTHOR CONTRIBUTIONS
BW and MO involved in selection of study, data extraction, quality assessment, statistical analysis, results interpretation and writing the initial, and final drafts of the manuscript. EB, LT, TB, and HA were involved in data extraction, quality assessment, statistical analysis, and writing drafts of the manuscript. All authors proofread and approved the final manuscript.