Factors Associated with Obstetric Anal Sphincter Injury During Vacuum-Assisted Vaginal Delivery

INTRODUCTION AND HYPOTHESIS

Obstetric anal sphincter injury (OASI) is a major complication associated with vacuum-assisted vaginal delivery (VAVD). The aim of this study was to evaluate risk factors related to vacuum extraction that are associated with OASI.

METHODS

This was a case-control study performed at a tertiary university teaching hospital. Included were patients aged 18-45 years who had a singleton pregnancy resulting in a live, term, VAVD. The study group consisted of women diagnosed with OASI following vacuum extraction. The control group included women following VAVD without OASI. Matching at a ratio of 1:2 was performed. Groups were compared regarding demographic, obstetric. and labor-related parameters, specifically focusing on variables related to the vacuum procedure itself.

RESULTS

One hundred and ten patients within the study group and 212 within the control group were included in the final analysis. Patients in the OASI group were more likely to undergo induction of labor, use of oxytocin during labor, increased second stage of labor, higher likelihood of the operator being a resident, increased number of pulls, procedure lasting under 10 min, occipito-posterior head position at vacuum initiation, episiotomy, increased neonatal head circumference, and birthweight. Multivariate logistic regression analysis revealed that increased week of gestation (OR 1.67, 95% CI 1.25-2.22, p < 0.001), unsupervised resident performing the procedure (OR 4.63, 95% CI 2.17-9.90), p < 0.001), indication of VAVD being fetal distress (OR 2.72, 95% CI 1.04-7.10, p = 0.041), and length of procedure under 10 min (OR 4.75, 95% CI 1.53-14.68, p = 0.007) were associated with OASI. Increased maternal age was associated with lower risk of OASI (OR 0.9, 95% CI 0.84-0.98, p = 0.012).

CONCLUSIONS

When performing VAVD, increased week of gestation, unsupervised resident performing the procedure, fetal distress as vacuum indication, and vacuum procedure under 10 min were associated with OASI. In contrast, increased maternal age was shown to be a protective factor.

Prediction models for perineal lacerations during childbirth: A systematic review and critical appraisal

BACKGROUND

Perineal lacerations could lead to substantial morbidities for women. A reliable prediction model for perineal lacerations has the potential to guide the prevention. Although several prediction models have been developed to estimate the risk of perineal lacerations, especially third- and fourth-degree perineal lacerations, the evidence about the model quality and clinical applicability is scarce.

OBJECTIVES

To systematically review and critically appraise the existing prediction models for perineal lacerations.

METHODS

Seven databases (PubMed, Embase, The Cochrane Library, Cumulative Index to Nursing and Allied Health Literature, SinoMed, China National Knowledge Infrastructure, and Wanfang Data) were systematically searched from inception to July 2022. Studies that developed prediction models for perineal lacerations or performed external validation of existing models were considered eligible to include in the systematic review. Two reviewers independently conducted data extraction according to the Checklist for critical Appraisal and data extraction for systematic Reviews of prediction Modelling Studies. The risk of bias and the applicability of the included models were assessed with the Prediction Model Risk of Bias Assessment Tool. A narrative synthesis was performed to summarize the characteristics, risk of bias, and performance of existing models.

RESULTS

Of 4345 retrieved studies, 14 studies with 22 prediction models for perineal lacerations were included. The included models mainly aimed to estimate the risk of third- and fourth-degree perineal lacerations. The top five predictors used were operative vaginal birth (72.7 %), parity/previous vaginal birth (63.6 %), race/ethnicity (59.1 %), maternal age (50.0 %), and episiotomy (40.1 %). Internal and external validation was performed in 12 (54.5 %) and seven (31.8 %) models, respectively. 13 studies (92.9 %) assessed model discrimination, with the c-index ranging from 0.636 to 0.830. Seven studies (50.0 %) evaluated the model calibration using the Hosmer-Lemeshow test, Brier score, or calibration curve. The results indicated that most of the models had fairly good calibration. All the included models were at higher risk of bias mainly due to unclear or inappropriate methods for handling missing data and continuous predictors, external validation, and model performance evaluation. Six models (27.3 %) showed low concerns about applicability.

CONCLUSIONS

The existing models for perineal lacerations were poorly validated and evaluated, among which only two have the potential for clinical use: one for women undergoing vaginal birth after cesarean delivery, and the other one for all women undergoing vaginal birth. Future studies should focus on robust external validation of existing models and the development of novel models for second-degree perineal laceration.

PROSPERO REGISTRATION NUMBER

CRD42022349786.

TWEETABLE ABSTRACT

The existing models for perineal lacerations during childbirth need external validation and updating. Tools are needed for second-degree perineal laceration.

Selective versus routine use of episiotomy for vaginal births in Shanghai hospitals, China: a comparison of policies

Background

To assess the effects of policy of selective versus routine episiotomy on mother and baby for women delivering vaginally in Shanghai and whether the hospital type has any effect on the outcomes.

Method

This was a multi-center retrospective cohort study in Shanghai between March 2015 and May 2017. The study population were vaginal births with selective or routine episiotomy (n = 5478) in 20 secondary or tertiary hospitals. Main Outcome Measure was the incidence of severe perineal lacerations. The adjusted odds ratios (aOR) and 95% confidence intervals (CI) were estimated by logistic regression and presented as the effect sizes. All models were stratified by the utilization of level (secondary and tertiary) and type (general and Obstetric) of hospital.

Results

The primary outcome was not significantly different between vaginal births with routine and selective episiotomy. Patients with selective episiotomy had a lower risk of postpartum hemorrhage, and newborns in the selective episiotomy group had a lower risk of shoulder dystocia and Neonatal Ward compared to those with routine episiotomy. Newborns in selective episiotomy group had a lower risk of birth injury in tertiary hospital. However, newborns in selective episiotomy group had a higher risk of birth injury in general hospitals.

Conclusion

Selective episiotomy is safe and can be recommended over routine episiotomy in obstetric and tertiary hospital settings in China.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-022-04790-0.

Obstetric Perineal Tears in Pregnant Adolescents and the Influencing Factors

STUDY OBJECTIVE

The incidence and risk factors of obstetric perineal tear occurrence in vaginal delivery of adolescent pregnant patients are not well established. We aimed to describe the incidence of obstetric perineal tears in adolescents and the maternal obstetric risk factors associated with this situation.

DESIGN

Retrospective cohort study SETTING: Department of Obstetrics and Gynecology, Tepecik Education and Research Hospital, Izmir, Turkey PARTICIPANTS: Adolescent pregnant patients (≤19 years) who delivered vaginally in our institution between January 2014 and January 2021 INTERVENTIONS AND MAIN OUTCOME MEASURES: The main outcome measures were the incidence of perineal tears, the degree of perineal tears, and the risk factors associated with severe perineal tears in adolescents. Severe perineal tears include third- and fourth-degree lacerations. A third-degree tear is defined as partial or complete disruption of the anal sphincter muscles, and a fourth-degree tear is defined as lacerations involving the rectal mucosa.

RESULTS

A total of 3441 adolescents who had a vaginal delivery were included in the study. The rate of severe perineal tear was 5.8% (200/3441). Risk factors associated with obstetric laceration in adolescents in multivariate analysis were nulliparity (OR = 1.72; 95% CI, 1.14-2.41; P = 0.007), high birth weight (OR = 4.1; 95% CI, 2.71-6.21; P < 0.001), and labor induction (OR = 1.36; 95% CI, 1.01-1.85; P = 0.02). Spontaneous onset of labor and previous delivery reduced the risk of severe perineal tear in adolescent pregnant patients (respectively, OR = 0.68; 95% CI, 0.51-0.94; P = 0.02 and OR = 0.51; 95% CI, 0.33-0.79; P = 0.007).

CONCLUSIONS

In adolescents, the risk of severe perineal tear was associated with nulliparity, birth weight, and labor induction. The only possible modifiable risk factor was labor induction.

Postpartum urinary incontinence and birth outcomes as a result of the pushing technique: a systematic review and meta-analysis

INTRODUCTION AND HYPOTHESIS

Directed pushing while using the Valsalva maneuver is shown to lead to bladder neck descent, especially in women with urinary incontinence (UI). There is insufficient evidence about the benefits or adverse effects between the pushing technique during the second stage of labor and urinary incontinence postpartum. The objective of this study was to evaluate the effects of the pushing technique for women during labor on postpartum UI and birth outcomes.

METHODS

Scientific databases were searched for studies relating to postpartum urinary incontinence and birth outcomes when the pushing technique was used from 1986 until 2020. RCTs that assessed healthy primiparas who used the pushing technique in the second stage of labor were included. In accordance with Cochrane Handbook guidelines, risk of bias was assessed and meta-analyzed. Certainty of evidence was assessed using the GRADE approach.

RESULTS

Seventeen RCTs (4606 primiparas) were included. The change in UI scores from baseline to postpartum was significantly lower as a result of spontaneous pushing (two studies; 867 primiparas; standardized mean difference: SMD -0.18, 95% CI -0.31 to -0.04). Although women were in the recumbent position during the second stage, directed pushing group showed a significantly shorter labor by 21.39 min compared with the spontaneous pushing group: there was no significant difference in the duration of the second stage of labor between groups.

CONCLUSIONS

Primiparas who were in the upright position and who experienced spontaneous pushing during the second stage of labor could reduce their UI score from baseline to postpartum.

Obstetric anal sphincter injury in adolescent mothers

Background

Obstetric anal sphincter injury (OASI) is a debilitating complication of vaginal delivery which has yet to receive ample attention in adolescents. The aim of this study was to describe risk for OASI in adolescent mothers compared to adults. We further attempted to compare risk factors for OASI between these two age groups.

Methods

We performed a retrospective cohort study between 2003 and 2019. Primiparous women who delivered vaginally, 21 years and younger were compared to women ages 26–35. Excluded were preterm, multifetal, non-vertex, cesarean deliveries as well as intrauterine fetal death. Rate of OASI as well as obstetric and labor characteristics of women with OASI, were compared between groups. Finally, risk factors were assessed for each group separately. Univariate and multivariate logistic regression model were performed.

Results

Final analysis was performed on 5113 nulliparous adolescents and 13,845 nulliparous in the 26–35 age group. Allocation to study groups was according to OASI – Sixty-seven adolescents (1.3%) had a 3rd or 4th degree perineal tear and were defined as the OASI group, while 5046 patients (98.7%) did not have such a tear. In the adult group, 199 out of 13,845 patients (1.4%) were diagnosed with OASI. Occurrence of OASI did not differ between groups (p = 0.510). Comparison of women with OASI in the adolescent group vs. adult group found differences with regard to operative vaginal delivery, (20.9% vs. 36.2%, respectively; p = 0.023) and meconium stained amniotic fluid (9.1% vs. 21.3%, respectively; p = 0.027).

Following multivariate analysis the only parameter independently associated with OASI in the adolescent age group was head circumference ≥ 90th percentile with an adjusted odds ratio of 3.08 (CI 1.48–6.38, p = 0.003). In the adult group the similar analysis revealed operative vaginal delivery (OR = 2.44, CI 1.72–3.47, p < 0.001) and a birthweight≥90th percentile (OR = 2.23, CI 1.19–4.18, p = 0.012) to be independent risk factors for OASI.

Conclusion

Adolescents have similar risk for OASI compared to adults but differ in risk factors leading to OASI. Head circumference ≥ 90th percentile was found to be associated with OASI in this age group.

Risk factors for severe perineal trauma during childbirth: An updated meta-analysis

Several studies have investigated the importance of maternal, fetal factors and intrapartum characteristics in predicting severe perineal lacerations. The purpose of the present systematic review is to accumulate current evidence and provide estimated effect sizes for the various risk factors described. We reviewed Medline, Scopus, Clinicaltrials.gov, EMBASE, Cochrane Central Register of Controlled Trials CENTRAL and Google Scholar for published studies in the field for observational studies as well as randomized controlled trials. Two researchers independently assessed the included studies and documented outcomes. Data extraction was performed using a modified data form that was based in Cochrane`s data collection form for intervention reviews for RCTs and non-RCTs. Forty-three articles were selected for inclusion in the present systematic review. The analyzed population reached 716,031 parturient of whom 22,280 (3,1%) sustained third- and fourth-degree perineal lacerations. Several risk factors were identified. Instrumental delivery [RR 3.38 (2.21, 5.18)], midline episiotomy [RR 2.88 (1.79, 4.65)] and a persistent occiput posterior position [RR 2.73 (2.08, 3.58)] were associated with the higher risk of developing severe perineal lacerations. Mediolateral episiotomy did not increase, but was also not protective against perineal lacerations [RR 1.55 (0.95, 2.53)]. Several factors contribute to the development of severe perineal lacerations. The present meta-analysis presents accumulated data that may help physicians estimate risks and provide appropriate patient counseling.

Prevalence and Location of Obstetric Lacerations in Adolescent Mothers

STUDY OBJECTIVE

The objective of this study was to describe prevalence and location of obstetric lacerations in adolescents.

DESIGN

Retrospective cohort study.

SETTING

We performed an analysis of the Consortium on Safe Labor database including tertiary care university-affiliated urban hospitals.

PARTICIPANTS

All primiparous women who delivered vaginally were included.

INTERVENTIONS

Vaginal and perineal lacerations were compared between age groups 15 or younger, 16-21, 22-34, 35-39, and older than 40 years.

MAIN OUTCOME MEASURES

Outcome measures included vaginal, perineal, labial, and periurethral lacerations. χ² and Fisher exact tests were used as appropriate, with P < .05 considered significant.

RESULTS

A total of 9777 patients were included in the analysis. Young adolescents and adolescents had significantly higher rates of labial and periurethral lacerations compared with individuals aged 22-34 years. The prevalence of third- and fourth-degree perineal tears increased with age.

CONCLUSION

Adolescent primiparous women are less likely to have severe perineal obstetric tears, but have higher rates of labial and periurethral tears.

Duration of second stage of labor and instrumental delivery as risk factors for severe perineal lacerations: population-based study

Background

We sought to investigate the impact of the duration of second stage of labor on risk of severe perineal lacerations (third and fourth degree).

Methods

This population based cohort study was conducted in the Stockholm/Gotland region, Sweden, 2008–2014. Study population included 52 211 primiparous women undergoing vaginal delivery with cephalic presentation at term. Unconditional logistic regression analysis was used to calculate crude and adjusted odds ratios (OR), using 95% confidence intervals (CI). Main exposure was duration of second stage of labor, and main outcome was risks of severe perineal lacerations (third and fourth degree).

Results

Risk of severe perineal lacerations increased with duration of second stage of labor. Compared with a second stage of labor of 1 h or less, women with a second stage of more than 2 h had an increased risk (aOR 1.42; 95% CI 1.28–1.58). Compared with non-instrumental vaginal deliveries, the risk was elevated among instrumental vaginal deliveries (aOR 2.24; 95% CI 2.07–2.42). The risk of perineal laceration increased with duration of second stage of labor until less than 3 h in both instrumental and non-instrumental vaginal deliveries, but after 3 h, the ORs did not further increase. After adjustments for potential confounders, macrosomia (birth weight > 4 500 g) and occiput posterior fetal position were risk factors of severe perineal lacerations.

Conclusions

The risk of severe perineal laceration increases with duration until the third hour of second stage of labor. Instrumental delivery is the most significant risk factor for severe lacerations, followed by duration of second stage of labor, fetal size and occiput posterior fetal position.

A comparison of the "hands-off" and "hands-on" methods to reduce perineal lacerations: a randomised clinical trial

OBJECTIVE

The objective of the current study was to compare the "Hands-off" and "Hands-on" methods to reduce perineal lacerations.

METHOD

We conducted a randomized controlled trial to compare the effectiveness of two techniques for perineum protection during spontaneous delivery. Study participants included 600 nulliparous expectant mothers, who were divided equally between the "hands off" and "hands on" groups (n_300 per group).

FINDINGS

A total of 147 (49 %) women in the "Hands-on" and 143 women (47.7 %) in the "Hand -off" groups encountered perineal trauma (p = 0.74). In the "Hands-on" group, 8 women (2.7 %) experienced a third degree trauma compared with (0.3 %) that in the "Hands-off" method (p = 0.1). Episiotomy was performed on 38 women (12.7 %) from the "Hands-on" and 17 (5.7 %) women from the "Hands-off" (p = 0.003) groups. In addition, 28 women (9.3 %) from the "Hands-on" group and 47 women (15.7 %) from the "Hands-off" group experienced periurethral tears (p = 0.01) that did not need mending.

CONCLUSION

Application of the "Hands-off" method for vaginal delivery has a positive effect on the mother's health because of the reduction of Episiotomy and third degree tearing. Therefore, we conclude that the "Hands-off" method offers a safer alternative for perineal control during labor.

[Variability in the rate of episiotomies and its relation to severe perineal tears and neonatal morbility]

OBJECTIVE

To determine the variability in the use of episiotomy among midwives and its relation to third and fourth-degree tears, and the impact on neonatal morbidity.

METHOD

A study was conducted on historical groups from a total of 2,366 eutocic births with a single live fetus greater than or equal to 37 weeks gestation and 18 midwives over a three year period (2009, 2010 and 2011) in "Mancha-Centro" Hospital (Alcázar de San Juan).The outcomes variables for this analysis were the incidence of episiotomy, perineal lacerations, and neonatal morbidity.

RESULTS

The variability in the use of episiotomy ranged from 19.5% to 50.1% among the 18 midwives in the study, with an average rate of 34.9% (824). Grouped at intervals, 22.1% (524) had a rate of ≤25%, 26.1% (621) between 26-35%, 38% (898) between 36-44%, and 13.7% (323) a rate of ≥45%, with homogeneity between the groups for all the confounding factors. There was no statistical association between higher rates of episotomy and pH of umbilical artery<7.10, Apgar score after 5 min<7, and the level of neonatal resuscitation type iii and iv. There was also no relationship between the rate of episiotomy with perineal integrity and third and fourth-degree tears.

DISCUSSION

The variability in the rate of episiotomy is high, and it is not related to the increased presence of third and fourth-degree tears or increased neonatal morbidity. Episiotomy rates should not be greater than 25%, in order to prevent perineal trauma or loss of fetal well-being.

Occurrence and surgical repair of third degree perineal lacerations in adult female camels (Camelus dromedarius) by one-stage (Goetz) technique

Retrospective analysis of third degree perineal lacerations in 7 female camels (6-17 yrs of age) that were surgically corrected by one stage repair (Goetz technique) is presented. Majority (3/7) of the camels was primiparous and all parturitions had a history of calving assistance. Six (6/7) camels recovered by first intention of healing. Dehiscence of perineal structure occurred in only one camel due to infection and healed by second intention. Subsequent matings resulted in pregnancy in four camels and one camel died due to unrelated causes. We conclude that perineal lacerations can occur in primiparous camels with difficult assisted deliveries and that one stage repair of perineal lacerations in camels improves the perineal conformation and such camels may easily regain normal fertility.