Prospective comparison of obstetric anal sphincter injury incidence between an Asian and Western hospital

Maternal origin matters: Country of birth as a risk factor for obstetric anal sphincter injuries

OBJECTIVE

Obstetric anal sphincter injuries (OASIS) are severe complications to vaginal births with potential long-term consequences. Maternal origin has been proposed to affect the overall risk, but the association and underlying explanation are uncertain. The objective was to assess the association between maternal country of birth and OASIS.

METHODS

A Swedish nationwide cohort study including singleton term vaginal births during 2005-2016. Data were extracted from the Swedish Medical Birth Registry and Statistics Sweden. Modified Poisson regression analyses were performed to obtain crude and adjusted risk ratios (RRs). Adjustments were made in four cumulative steps. Sub-analyses were performed to investigate the risk of OASIS associated with female genital circumcision (FGC).

RESULTS

In all, 988 804 births were included. The rate of OASIS in Swedish-born women was 3.5%. Women from East/Southeast Asia had an increased risk of OASIS (adjusted RR [aRR] 1.71, 95% confidence interval [CI] 1.60-1.83), as did women born in Sub-Saharan Africa (aRR 1.60, 95% CI 1.49-1.72). The risk remained significantly increased also after adjustment for maternal height. By contrast, women from South/Central America had a decreased risk of OASIS (aRR 0.65, 95% CI 0.56-0.76). FGC was associated with an increased risk of OASIS (aRR 3.05, 95% CI 2.60-3.58). Episiotomy appeared to have an overall protective effect (aRR 0.95, 95% CI 0.92-0.98), but not significantly more protective among women with female genital mutilation.

CONCLUSIONS

Country of birth plays an important role in the risk of OASIS. Women from East/Southeast Asia and Sub-Saharan Africa are at significantly increased risk as compared with Swedish-born women, whereas women from South/Central America are at lower risk. FGC is also a significant risk factor for OASIS.

Effects of Perineal Warm Compresses during the Second Stage of Labor on Reducing Perineal Trauma and Relieving Postpartum Perineal Pain in Primiparous Women: A Systematic Review and Meta-Analyses

Non-pharmaceutical midwifery techniques, including perineal warm compresses, to improve maternal outcomes remain controversial. The aims of this study are to assess the effects of perineal warm compresses on reducing perineal trauma and postpartum perineal pain relief. This systematic review included randomized controlled trials (RCTs). We searched seven bibliographic databases, three RCT register websites, and two dissertation databases for publications from inception to 15 March 2023. Chinese and English publications were included. Two independent reviewers conducted the risk of bias assessment, data extraction, and the evaluation of the certainty of the evidence utilizing the Cochrane risk of bias 2.0 assessment criteria, the Review Manager 5.4, and the online GRADEpro tool, respectively. Seven RCTs involving 1362 primiparous women were included. The combined results demonstrated a statistically significant reduction in the second-, third- and/or fourth- degree perineal lacerations, the incidence of episiotomy, and the relief of the short-term perineal pain postpartum (within two days). There was a potential favorable effect on improving the integrity of the perineum. However, the results did not show a statistically significant supportive effect on reducing first-degree perineal lacerations and the rate of perineal lacerations requiring sutures. In summary, perineal warm compresses effectively reduced the second-, third-/or fourth-degree perineal trauma and decreased the short-term perineal pain after birth.

Asian-White disparities in obstetric anal sphincter injury: a systematic review and meta-analysis

OBJECTIVE

Obstetrical anal sphincter injury describes a severe injury to the perineum and perianal muscles after birth. Obstetrical anal sphincter injury occurs in approximately 4.4% of vaginal births in the United States; however, racial and ethnic inequities in the incidence of obstetrical anal sphincter injury have been shown in several high-income countries. Specifically, an increased risk of obstetrical anal sphincter injury in individuals who identify as Asian vs those who identify as White has been documented among residents of the United States, Australia, Canada, Western Europe, and the Scandinavian countries. The high rates of obstetrical anal sphincter injury among the Asian diaspora in these countries are higher than obstetrical anal sphincter injury rates reported among Asian populations residing in Asia. A systematic review and meta-analysis of studies in high-income, non-Asian countries was conducted to further evaluate this relationship.

DATA SOURCES

MEDLINE, Ovid, Embase, EmCare, and the Cochrane databases were searched from inception to March 2023 for original research studies.

STUDY ELIGIBILITY CRITERIA

Observational studies using keywords and controlled vocabulary terms related to race, ethnicity and obstetrical anal sphincter injury. All observational studies, including cross-sectional, case-control, and cohort were included. 2 reviewers followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and the Meta-analysis of Observational Studies in Epidemiology recommendations.

METHODS

Meta-analysis was performed using RevMan (version 5.4; Cochrane Collaboration, London, United Kingdom) for dichotomous data using the random effects model and the odds ratios as effect measures with 95% confidence intervals. Subgroup analysis was performed among Asian subgroups. The risk of bias was assessed using the Joanna Briggs Institute Critical Appraisal tools. Meta-regression was used to determine sources of between-study heterogeneity.

Results

A total of 27 studies conducted in 7 countries met the inclusion criteria encompassing 2,337,803 individuals. The pooled incidence of obstetrical anal sphincter injury was higher among Asian individuals than White individuals (pooled odds ratio, 1.64; 95% confidence interval, 1.48-1.80). Subgroup analyses showed that obstetrical anal sphincter injury rates were highest among South Asians and among population-based vs hospital-based studies. Meta-regression showed that moderate heterogeneity remained even after accounting for differences in studies by types of Asian subgroups included, study year, mode of delivery included, and study setting.

Conclusion

Obstetrical anal sphincter injury is more frequent among Asian versus white birthing individuals in multiple high-income, non-Asian countries. Qualitative and quantitative research to elucidate underlying causal mechanisms responsible for this relationship are warranted.

Neonatal head circumference as a risk factor for obstetric anal sphincter injuries: a systematic review and meta-analysis

OBJECTIVE

Between 53% and 79% of women will sustain some degree of perineal laceration during vaginal delivery. Third- and fourth-degree perineal lacerations are known as obstetric anal sphincter injuries. Timely diagnosis and prompt treatment of obstetric anal sphincter injuries can help to prevent the development of severe consequences like fecal incontinence, urinary incontinence, and rectovaginal fistula. Neonatal head circumference is routinely measured postpartum but is often not mentioned as a risk factor for obstetric anal sphincter injuries in clinical guidelines. Thus far, no review article on the risk factors for obstetric anal sphincter injuries has discussed the role of neonatal head circumference. This study aimed to review and analyze the relationship between head circumference and the occurrence of obstetric anal sphincter injuries among previous studies to conclude whether head circumference should be recognized as an important risk factor.

DATA SOURCES

Through study screening on Google Scholar, PubMed, Scopus, and Science Direct for articles published between 2013 to 2023, followed by assessment of eligibility, this study ended up reviewing 25 studies, 17 of which were included in the meta-analysis.

STUDY ELIGIBILITY CRITERIA

Only studies that reported both the neonatal head circumference and the occurrence of obstetric anal sphincter injuries were included in this review.

METHODS

The included studies were appraised using the Dartmouth Library risk of bias assessment checklist. Qualitative synthesis was based on the study population, findings, adjusted confounding factors, and suggested causative links in each study. Quantitative synthesis was conducted using calculation and pooling of odds ratios and inverse variance using Review Manager 5.4.1.

RESULTS

A statistically significant association between head circumference and obstetric anal sphincter injuries was reported in 21 of 25 studies; 4 studies reported that head circumference was a true independent risk factor. A meta-analysis of the studies that reported neonatal head circumference as a dichotomous categorical variable with a cutoff point of 35±1 cm yielded statistically significant pooled results (odds ratio, 1.92; 95% confidence interval, 1.80-2.04).

CONCLUSION

The risk for obstetric anal sphincter injuries increased as the neonatal head circumference increased-this should be considered in decision-making during labor and postpartum management to attain the best outcome.

Women's experiences of anal incontinence following vaginal birth: A qualitative study of missed opportunities in routine care contacts

OBJECTIVES

This study aimed to explore experiences of women with anal incontinence following a childbirth injury, and to identify areas of missed opportunities within care they received.

DESIGN

This is a qualitative study involving semi-structured interviews.

SETTING

Participants were recruited via five hospitals in the UK, and via social media adverts and communication from charity organisations.

PARTICIPANTS

Women who have experienced anal incontinence following a childbirth injury, either within 7 years of sustaining the injury, or if they identified new, or worsening symptoms of AI at the time of menopause.

MAIN OUTCOME MEASURES

Main outcomes are experiences of women with anal incontinence following childbirth injury, and missed opportunities within the care they received.

RESULTS

The following main themes were identified: opportunities for diagnosis missed, missed opportunities for information sharing and continuity and timeliness of care.

CONCLUSIONS

Anal Incontinence following a childbirth injury has a profound impact on women. Lack of information and awareness both amongst women and healthcare professionals contributes to delays in accurate diagnosis and appropriate treatment.

What are the factors that may predict the severity of perineal tears in obstetric anal sphincter injuries and how are their outcomes? A 10-year retrospective analysis in a Southeast Asian population

INTRODUCTION AND HYPOTHESIS

Obstetric anal sphincter injuries (OASIS) complicate around 1-2% of deliveries in low- and middle-income countries. Asians are twice more likely to suffer this complication. The 3c and 4th-degree perineal tears that involve the internal anal sphincter muscle and the anal mucosa have been reported to have a poorer outcome and higher risk of recurrence compared to less severe tears.

METHODOLOGY

A retrospective 10-year analysis of third- and fourth-degree perineal tears in a tertiary centre was conducted. The maternal, neonatal factors and their respective outcomes after the repair of an OASI were examined and compared between minor (3a and 3b perineal tears) and major anal sphincter tears (3c and 4th-degree perineal tears).

RESULTS

Five hundred twenty patients with OASIS were included into the study. Birthweight ≥ 3.5 kg was significantly associated with having a major anal sphincter tear in this study population, OR 1.91 (95% CI 1.21-3.02), p = 0.006. There was no significant difference in having faecal or flatus incontinence after the repair; however, major anal sphincter tears appeared to be more complicated to repair compared to minor anal sphincter tears, requiring involvement of the consultant, p < 0.001.

CONCLUSION

Neonatal birthweight ≥ 3.5 kg was the most significant factor in predicting the severity of OASIS in this study population. After appropriate repair, the rates of reported complications appeared similar between the two groups. However, significantly more expertise and resources were required for the repair of higher degree OASIS.

Obstetric anal sphincter injury by maternal origin and length of residence: a nationwide cohort study

OBJECTIVE

To estimate the association between maternal origin and obstetric anal sphincter injury (OASI), and assess if associations differed by length of residence.

DESIGN

Population-based cohort study.

SETTING

The Medical Birth Registry of Norway.

POPULATION

Primiparous women with vaginal livebirth of a singleton cephalic fetus between 2008 and 2017 (n = 188 658).

METHODS

Multivariable logistic regression models estimated adjusted odds ratios (aORs) for OASI with 95% CI by maternal region of origin and birthplace. We stratified models on length of residence and paternal birthplace.

MAIN OUTCOME MEASURES

OASI.

RESULTS

Overall, 6373 cases of OASI were identified (3.4% of total cohort). Women from South Asia were most likely to experience OASI (6.2%; aOR 2.24, 95% CI 1.87-2.69), followed by those from Southeast Asia, East Asia & the Pacific (5.7%; 1.59, 1.37-1.83) and Sub-Saharan Africa (5.2%; 1.85, 1.55-2.20), compared with women originating from Norway. Among women born in the same region, those with short length of residence in Norway (0-4 years), showed the highest odds of OASI. Migrant women across most regions of origin had the lowest risk of OASI if they had a Norwegian partner.

CONCLUSIONS

Primiparous women from Asian regions and Sub-Saharan Africa had up to two-fold risk of OASI, compared with women originating from Norway. Migrants with short residence and those with a foreign-born partner had higher risk of OASI, implying that some of the risk differential is due to sociocultural factors. Some migrants, especially new arrivals, may benefit from special attention during labour to reduce morbidity and achieve equitable outcomes.

TWEETABLE ABSTRACT

Anal sphincter injury during birth is more common among Asian and Sub-Saharan migrants and particularly among recent arrivals.

Knowledge, attitude and experience of episiotomy practice among obstetricians and midwives: a cross-sectional study from China

OBJECTIVE

Episiotomy is still performed widely by obstetricians and midwives in some Chinese maternity units, but the reasons are unknown. This study aims to determine the knowledge, attitude and experience towards the practice of episiotomy among obstetricians and midwives in China's public hospitals and consider strategies to reduce its practice.

METHODS

A cross-sectional web survey using a self-administered questionnaire was conducted among obstetricians and midwives in 90 public hospitals in Henan Province, China.

RESULTS

900 (82.21%) participants completed the questionnaire. Average knowledge level (4.15, SD=1.10) on complications and overuse was identified among participants. Episiotomy was performed more frequently in secondary hospitals than in tertiary hospitals (p<0.05). Senior clinicians were more likely to perform episiotomy than younger ones (p<0.05). Almost half of the clinicians (42.11%) considered the current rate of episiotomy (45%) to be right or too low. The most common reason for performing episiotomy identified by obstetricians (83.94%) and midwives (79.69%) was to reduce third-degree or fourth-degree perineal laceration. Both obstetricians (80.29%) and midwives (82.57%) agreed that the most significant obstacle to reducing the rate of episiotomy was lack of training on reducing perineal tears.

CONCLUSION

In sum, episiotomy was driven by previous training, practitioners' experience and local norms rather than the latest medical evidence. Clinicians in secondary hospitals and senior clinicians are key training targets. It is urgent to improve current clinical policies and surgical procedure guidelines for obstetricians and midwives regarding episiotomy.

'Please Squeeze': A novel approach to perineal guarding at the time of delivery reduced rates of obstetric anal sphincter injury in an Australian tertiary hospital

BACKGROUND

Over the last decade the incidence of obstetric anal sphincter injuries (OASIS) has been steadily increasing locally and internationally. Investigations into reducing rates, and the long-term complications, of OASIS are required.

AIMS

To determine if applying a new method of perineal guarding at the time of delivery reduces the incidence of OASIS at an Australian tertiary hospital.

MATERIALS AND METHODS

A retrospective audit was performed for the three  years prior to and following mandatory introduction of a new method of perineal guarding. The novel 'Please Squeeze' technique involved placement of the accoucheur's thumb and index finger just above the line of the posterior fourchette at crowning and bringing them firmly one centimetre postero-medially to reduce tension. Demographic data were extracted from the unit's obstetric database (ObstetriX).

RESULTS

There were 9453 deliveries prior to, and 9805 deliveries following commencement of 'Please Squeeze', with no difference in the incidence of caesarean (30.4% vs 30.3% P = 0.87) or forceps (6.3% vs 5.8% P = 0.14) between groups. The incidence of primiparas (P = 0.005), ventouse (P < 0.001) and spontaneous vaginal deliveries (SVD) (P = 0.005) between groups. There was a clinically important 20% reduction in the incidence of OASIS across all vaginal deliveries from 3.5% to 2.8% (P = 0.006). In SVD, there was a 20% decrease in OASIS from 2.4% to 2.2% (P = 0.02), and a 14% decrease in OASIS with assisted vaginal delivery from 8% to 7.3% (P = 0.002). The incidence of episiotomy increased 16% (P < 0.001).

CONCLUSIONS

The novel 'Please Squeeze' perineal guarding method contributed to a reduced incidence of OASIS in an Australian tertiary hospital.

The impact of maternal body mass index on the rate of obstetric anal sphincter injury in nulliparous women: A Victorian retrospective cohort study

BACKGROUND

Maternal obesity is an important comorbidity in contemporary obstetrics practice and is associated with significantly increased perinatal complications. Obstetric anal sphincter injury (OASIS) sustained during labour can lead to faecal incontinence, chronic pain and effects on quality of life. Currently, it is unclear if maternal body mass index (BMI) influences the risk of sustaining OASIS.

AIM

To investigate the impact of increased BMI on the rate of OASIS among nulliparous women.

MATERIALS AND METHODS

A retrospective cohort study was conducted, which included nulliparous women with singleton, vaginal deliveries ≥37 weeks gestation at a Victorian regional centre between 2007 and 2017 (n = 3335). Logistic regression was performed to calculate unadjusted and adjusted odds ratios (aOR). Women were grouped by World Health Organization BMI categories, and the rates of OASIS were evaluated.

RESULTS

Women with a BMI ≥ 25 were significantly less likely to develop OASIS compared to women with a BMI < 25 (aOR 0.60, 95% CI 0.41-0.89). Women with a BMI ≥ 35 had significantly decreased odds of OASIS compared to normal weight women (aOR 0.27, 0.10-0.78). While not statistically significant, the odds of OASIS decreased with each increase in BMI class. Other statistically significant risk factors were maternal age, birth weight, forceps delivery, non-smokers (aOR 4.03, 1.46-11.1) and diabetes mellitus (aOR 9.48, 2.1-41.4).

CONCLUSION

Women with a BMI ≥ 25 were less likely to sustain OASIS compared to women with a BMI < 25. Furthermore, the odds of OASIS decreased for each increase in BMI category. These findings warrant further investigation into the mechanism of this protective effect.