Epidural analgesia and severe perineal tears: a literature review and large cohort study

Is epidural analgesia an independent risk factor for OASIS? A population-based cohort study

INTRODUCTION

To evaluate whether epidural analgesia is an independent risk factor for OASIS.

METHODS

A population-based cohort study including all women who delivered by spontaneous vaginal delivery or by instrumental delivery beyond 24 weeks gestation was conducted. Deliveries occurred between 1988 and 2016 at a large university tertiary medical center. Women with multiple gestations and those lacking prenatal care were excluded from the analysis.

RESULTS

During the study period, 252,542 women delivered at the Soroka University Medical Center and met the inclusion criteria. Of these, 583 (0.23%) were diagnosed with OASIS. Women with OASIS were more likely to be younger, nulliparous, with suspected fetal macrosomia, had higher rates of labor induction and vacuum extraction delivery, higher rates of conceiving after infertility treatments, more advanced gestational age at delivery, higher mean birth weight, higher rates of post-partum hemorrhage and need for blood transfusions. Use of epidural analgesia during pregnancy was significantly high among the OASIS group. Rates of episiotomy were not significantly different between the groups. Using a multimodal logistic regression model, after controlling for vacuum delivery, large for gestational age, nulliparity, gestational age, ethnicity, maternal age, induction of labor, fertility treatments, non-reassuring fetal heart rate and non-progressive second stage of labor, epidural analgesia was found to be significantly associated with OASIS.

CONCLUSION

Epidural analgesia was found to be an independent risk factor for OASIS in our population.

Re-evaluation of modifiable risk factors for obstetric anal sphincter injury in a real-world setting

INTRODUCTION AND HYPOTHESIS

The objective was to identify modifiable risk factors for obstetric anal sphincter injury (OASI) in primiparous women.

METHODS

This was a retrospective cohort study of primiparous women with a singleton vaginal delivery. Main outcome measures were incidence of OASI and odds ratios for possible risk factors: maternal age, body mass index and height, fetal birthweight and head circumference, gestational age, epidural analgesia, mediolateral episiotomy, and instrumental deliveries. Univariate and multivariate logistic regressions were performed using forward methods for variable selection.

RESULTS

Of 19,786 primiparous women with a singleton vaginal delivery, 369 sustained an OASI (1.9%). Risk factors were identified: vacuum extraction (adjusted OR 2.06, 95% CI, 1.59-2.65, p < 0.001), increased fetal weight (aOR 1.06, 95% CI, 1.02-1.11, p = 0.002, per 100-g increments); head circumference (aOR 1.24, 95% CI, 1.13-1.35, p < 0.001, per 1-cm increments); gestational week (aOR 1.11, 95% CI, 1.02-1.2, p = 0.012, per week). Protective factors: mediolateral episiotomy (aOR 0.75, 95% CI, 0.59-0.94, p = 0.013) particularly in vacuum deliveries (aOR 0.50, 95% CI, 0.29-0.97, p = 0.040); epidural analgesia (aOR 0.64, 95% CI, 0.48-0.84, p = 0.001); maternal height ≥157 cm (aOR 0.97, 95% CI, 0.96-0.98, p = 0.006, risk decreases by 2.6% per 1 cm increase in height).

CONCLUSIONS

Mediolateral episiotomy was protective against OASI in both spontaneous and instrumental deliveries of primiparae. Increased fetal weight and large fetal head circumference, particularly in short women, were significant risk factors. These findings support the performance of ultrasound to acquire updated fetal measures before admission to the labor ward.

Labor Neuraxial Analgesia and Its Association With Perinatal Outcomes in China in 2015-2016: A Propensity Score-Matched Analysis

BACKGROUND

The use of labor neuraxial analgesia (NA) in China has increased significantly in the past decade, and the current rate of use is unknown. This study aimed to describe the epidemiology of NA based on a large multicenter cross-sectional survey, the China Labor and Delivery Survey (CLDS) (2015-2016), and to evaluate the association between NA and intrapartum caesarean delivery (CD) and maternal and neonatal outcomes.

METHODS

The CLDS was a facility-based cross-sectional investigation with a cluster random sampling scheme conducted from 2015 to 2016. A specific weight was assigned to each individual based on the sampling frame. Logistic regression was adopted to analyze the factors associated with the use of NA. A propensity score matching scheme was used to analyze the associations between NA and intrapartum CD and perinatal outcomes.

RESULTS

A total of 51,488 vaginal deliveries or intrapartum CD were included in our study, excluding prelabor CDs. The weighted NA rate was 17.3% (95% confidence interval [CI], 16.6-18.0) in this survey population. Nulliparous, previous CD, hypertensive disorders, and labor augmentation were associated with higher use of NA. In the propensity score-matched analysis, NA was associated with reduced risks of intrapartum CD, especially intrapartum CD by maternal request (adjusted odds ratio [aOR], 0.68; 95% CI, 0.60-0.78 and aOR, 0.48; 95% CI, 0.30-0.76, respectively), 3rd or 4th degree perineal laceration (aOR, 0.36; 95% CI, 0.15-0.89), and 5-minute Apgar score ≤3 (aOR, 0.15; 95% CI, 0.03-0.66).

CONCLUSIONS

The use of NA may be associated with improved obstetric outcomes, including fewer intrapartum CD, less birth canal trauma, and better neonatal outcomes in China.

Influence of in utero fetal death on perineal tears in vaginal deliveries

The aim of this work was to evaluate and compare the incidence of perineal tears and Obstetrical anal sphincter injuries (OASIS) after vaginal delivery following a in utero fetal death (IUFD) compared with those with a live-birth. We conducted a single-center, retrospective cohort study using a database of all women who underwent a spontaneous vaginal delivery in the level III maternity ward. Exclusion criteria were breech presentation, cesarean section birth, instrumental delivery, multiple pregnancy, delivery before 24 + 6 weeks of gestation (WG) and termination of pregnancy for medical reasons. Women from the database were divided into two groups: an "in utero fetal death" (IUFD) group and a control group. Women were included in the IUFD group if they had a spontaneous vaginal delivery following a fetal demise after 24 + 6 WG in cephalic presentation between January 2006 and June 2020. Women in the "control" group were selected from the same database and were included if they underwent a spontaneous vaginal delivery of a live fetus in cephalic presentation, after 24 + 6 WG, during the same period. Each woman in the "IUFD" group was matched to two women (ratio 1:2) in the control group for parity, maternal age, body mass index, gestation and birth weight. The primary outcome was the presence of a sutured or unsutured perineal tear. During the study period, 31,208 patients delivered at a level III maternity hospital. Among them, 215 and 430 women were included in the IUFD group and the control group respectively. The two groups were comparable for all demographic and clinical characteristics except for an epidural analgesia (92% versus 70% in the control group, p < 0.01) and labor induction (86% versus 17% in the control group, p < 0.01). The incidence of any perineal tears was 13% (28/15) in the IUFD group versus 16% (70/430) in the control group. Relative risk of any perineal tears was non significative (RR = 0.8 IC95% [0.5-1.2]). The incidence of first-degree perineal tears was 10% in the IUFD group and 11% in the control group. The incidence of second-degree perineal tears was 18% in the IUFD group and 28% in the control group. Relative risk of first-degree perineal tears (RR = 0.88 95% CI [0.5-1.4]) and second-degree tears (RR = 0.51 95% CI [0.2-1.4]) were non significative. No obstetrical anal sphincter injury was found in either group. Vaginal delivery following a fetal demise did not appear to be either a risk factor or a protective factor for perineal tears. But there as a trend toward a lower incidence of second degree perineal tears in this context.

Knowledge and Attitudes towards Epidural Analgesia among Women of Childbearing Age in Jazan, Saudi Arabia: A Community-Based Cross-Sectional Study to Identify Predictors through Multivariate Modeling

Epidural analgesia (EA) is a central nerve blockade technique. It is linked to a significant reduction of labor pain and side effects. This study was designed to investigate the knowledge and attitudes towards EA among women of childbearing age (18-45 years) in Jazan, Saudi Arabia, and identify predictors through multivariate modeling. A random sampling technique (n = 680) was used for this cross-sectional, self-administered survey. A previously validated online questionnaire was distributed. After establishing a P value of less than 0.05 to denote statistical significance, SPSS was used to examine the data using descriptive analysis, the chi-square test of homogeneity, and multivariate logistic regression. Six hundred and eighty women were studied. Over 75% of the participants were university educated; less than half (46.3%) were 21-30 years old, students (42.2%), and had never been pregnant (49%). The previous mothers who had never had EA labor accounted for 64.6% (n = 347, 51.0%). "Family/friends" (39%), followed by "internet" (32%), were the most common sources of EA information. Those who correctly defined the EA accounted for 61.8%. Those who reported weak or no contractions after EA accounted for 32.2%. Those who said EA insertion hurt more than labor did accounted for 56.3%. Those women who said one should give consent to EA accounted for 83.1%. Those who believe EA is safe for the baby accounted for 50.1%. Those who knew about EA complications accounted for 24.34%. According to multivariate modeling, attitude score plays a significant role in determining the participant's knowledge level. This study found that childbearing women know a little about EA. Attitudes affected this knowledge level, and demographics did not. Cognitive intervention is needed to change these attitudes and spread EA-related knowledge.

Risk factors for obstetric anal sphincter injury among nulliparous of advanced maternal age

OBJECTIVE

Data regarding the risk factors for obstetrical anal sphincter injury (OASI) among nulliparous advanced maternal age (AMA) women are scarce. We aimed to evaluate the risk factors and the rate of OASI in this population.

METHODS

A retrospective case-control study of nulliparous women aged ≥35 who delivered vaginally between March 2011 and August 2021. The study cohort included nulliparous AMA women, aged 35 years or older, delivering vaginally a singleton, vertex neonate. We excluded cases with missing data. Maternal and intrapartum characteristics were compared between OASI and no-OASI groups. We matched groups to the earliest gestational age in which OASI has occurred.

RESULTS

A total of 3,635 women met inclusion criteria. Mean age of the participants was 38 years (range 35-56, interquartile range 36-39). The oldest age in which an OASI was diagnosed was 45. A total of 55 (1.5%) cases of OASI were diagnosed. Gestational age at delivery was higher in the OASI group compared to the no-OASI group (mean 39^6/7±1^2/7 vs. 39^1/7±2^3/7 weeks respectively, p=.039). The rate of induction of labor, oxytocin and epidural analgesia, prolonged second stage, mode of delivery, and rate of blood transfusion did not vary between groups. Estimated fetal weight was higher in the OASI group (3,324 ± 308 vs. 3,114 ± 566 g, p<.001). Sonographic abdominal circumference was higher in the OASI group (338 ± 13 vs. 328 ± 28 mm, p<.001). Mean birthweight was higher in the OASI group (3,286 ± 400 vs. 3,059 ± 541 g, p=.002) and the birthweight centile was higher as well (60 ± 26 vs. 52 ± 25, p=.024).In a multivariable regression analysis including birthweight, gestational age, operative vaginal delivery, epidural anesthesia, and hypertensive disorders-birthweight and hypertensive disorder were positively associated with an OASI odds ratio [OR 95% CI 1.6 (1.1-2.32) for every 500 g increase; 2.42 (1.006-5.82), respectively]. Epidural anesthesia was negatively associated with OASI [OR 95% CI 0.49) 0.27-0.87)].

CONCLUSIONS

Epidural anesthesia is the only modifiable risk factor and is protective against OASI among nulliparous AMA women. Birthweight and hypertensive disorders are also independent predictors of OASI in this population.

Risk of obstetric anal sphincter injury among women who birth vaginally after a prior caesarean section: A state-wide cohort study

OBJECTIVE

Vaginal birth after caesarean (VBAC) has been suggested to be associated with an increased risk of obstetric anal sphincter injury (compared with primiparous women who birth vaginally). However, prior studies have been small, or used outdated methodology. We set out to validate whether the risk of obstetric anal sphincter injury among women having their first VBAC is greater than that among primiparous women having a vaginal birth.

DESIGN

State-wide retrospective cohort study.

SETTING

Victoria, Australia.

POPULATION

All births (455,000) between 2009-2014.

METHODS

The risk of severe perineal injury between first vaginal birth and first vaginal birth after previous caesarean section was compared, after adjustment for potential confounding variables. Covariates were examined using logistic regression for categorical data and Wilcoxon rank-sum test for continuous data. Missing data were handled using multiple imputation; the analysis was performed using regression adjustment and Stata v16 multiple imputation and teffects suites.

RESULTS

Women having a VBAC (n=5,429) were significantly more likely than primiparous women (n=123,353) to sustain a 3^rd or 4^th degree tear during vaginal birth (7.1 vs 5.7%, p<0.001). After adjustment for mode of birth, body mass index, maternal age, infant birthweight, episiotomy and epidural, there was a 21% increased risk of severe perineal injury (relative risk 1.21 (95%CI 1.07 - 1.38)).

CONCLUSIONS

Women having their first vaginal birth after caesarean section have a significant increased risk of sustaining a 3^rd or 4^th degree tear, compared with primiparous women having a vaginal birth. Patient counselling and professional guidelines should reflect this increased risk.

Perineal trauma in nulliparous women and its associated factors

Introduction: Perineal trauma is an important complication for women after giving birth. Objective: To evaluate the prevalence of perineal trauma and its associated factors in nulliparous. Methods: A retrospective cohort study was carried out, through the analysis of the medical records of women with singleton pregnancy who achieved vaginal birth of a live infant, in 2017, in a maternity hospital. Data collection involved information about demographic, obstetric, and clinical data from nulliparous women, and infant birthweight. Univariate and multivariate logistic analyses were performed to verify the association of perineal trauma with the variables assessed, with significant variables remaining in the model (p<0.05), through a stepwise strategy. Results: A total of 326 medical records were analyzed. The percentage of perineal trauma was 60%. In the multivariate analysis, the use of oxytocin increased the chance of perineal trauma by 730%. In addition, the adoption of squatting position and hands and knees decreased the chances of perineal trauma by 81% and 97%, respectively, in comparison with those who adopted the lithotomy position, during the second stage labor. Conclusion: The rate of perineal laceration was high, but the severity was low. The use of oxytocin is associated with the presence of trauma and the squatting position and hands and knees, especially, have contributed to the protection of the perineum.

Episiotomy practices in France: epidemiology and risk factors in non-operative vaginal deliveries

Episiotomy use has decreased due to the lack of evidence on its protective effects from maternal obstetric anal sphincter injuries. Indications for episiotomy vary considerably and there are a great variety of factors associated with its use. The aim of this article is to describe the episiotomy rate in France between 2013 and 2017 and the factors associated with its use in non-operative vaginal deliveries. In this retrospective population-based cohort study, we included vaginal deliveries performed in French hospitals (N = 584) and for which parity was coded. The variable of interest was the rate of episiotomy, particularly for non-operative vaginal deliveries. Trends in the episiotomy rates were studied using the Cochran-Armitage test. Hierarchical logistic regression was used to identify variables associated with episiotomy according to maternal age and parity. Between 2013 and 2017, French episiotomy rates fell from 21.6 to 14.3% for all vaginal deliveries (p < 0.01), and from 15.5 to 9.3% (p < 0.01) for all non-operative vaginal deliveries. Among non-operative vaginal deliveries, epidural analgesia, non-reassuring fetal heart rate, meconium in the amniotic fluid, shoulder dystocia, and newborn weight (≥ 4,000 g) were risk factors for episiotomy, both for nulliparous and multiparous women. On the contrary, prematurity reduced the risk of its use. For nulliparous women, breech presentation was also a risk factor for episiotomy, and for multiparous women, scarred uterus and multiple pregnancies were risk factors. In France, despite a reduction in episiotomy use over the last few years, the factors associated with episiotomy have not changed and are similar to the literature. This suggests that the decrease in episiotomies in France is an overall tendency which is probably related to improved care strategies that have been relayed by hospital teams and perinatal networks.

The impact of a nationwide hands-on workshop on the diagnostic rates and management of obstetrical anal sphincter Injuries in Israel

AIM

The aim was to evaluate the influence of a half day, hands-on, workshop on the detection and repair of obstetric anal sphincter injuries (OASIs).

METHOD

Starting in February 2011, hands-on workshops for the diagnosis and repair of OASIs were delivered by trained urogynaecologists in departments of tertiary medical centres in Israel. The structure of the hands-on workshop resembles the workshop organized at the International Urogynecological Association annual conferences. Participants included medical staff, midwives and surgical residents from each medical centre. We collected data regarding the rate of OASIs, 1 year before and 1 year following the workshop, in 11 medical centres. The study population was composed of parturients with the following inclusion criteria: singleton pregnancy, vertex presentation and vaginal delivery. Pre-viable preterm gestations (< 24 weeks), birth weight < 500 g, stillborn, and those with major congenital anomalies, multifoetal pregnancies, breech presentations and caesarean deliveries were excluded from the analysis.

RESULTS

In the reviewed centres, 70 663 (49.3%) women delivered prior to the workshop (pre-workshop group) and 72 616 (50.7%) women delivered following the workshop (post-workshop group). Third- or fourth-degree perineal tears occurred in 248 women (0.35%) before the workshop, and in 328 (0.45%) following the workshop, a significant increase of 28.7% (P = 0.002). The increase in diagnosis was significant also in women with third-degree tears alone, 226 women (0.32%) before the workshop and 298 (0.41%) following the workshop, an increase of 28.3% (P = 0.005).

CONCLUSION

The detection rate of OASIs has significantly increased following the hands-on workshop. The implementation of such programmes is crucial for increasing awareness and detection rates of OASI following vaginal deliveries.

Obstetric anal sphincter injuries (OASIS) in multiparous women with the use of epidural anaesthesia: A retrospective cohort study

BACKGROUND

The use of epidural as a form of analgesia is increasingly common in labour, but this has shown to have been associated with increased rates of instrumental delivery, and prolonged second stage, resulting in increased rates of OASIS (Obstetric Anal Sphincter Injury).

AIMS

This study aimed to investigate the impact of epidural anaesthesia in multiparous women undergoing vaginal deliveries on OASIS and secondary maternal outcomes.

MATERIALS AND METHODS

A retrospective cohort study of multiparous women with singleton pregnancies delivering at term ≥37 weeks and the use of epidural analgesia in labour at a tertiary hospital in Melbourne, Victoria, Australia, the Royal Women's Hospital was undertaken between the period 2012-2018. Maternal outcomes were collated and dichotomised according to the presence of epidural use. Multiparous women with no prior history of a vaginal birth and non-cephalic presentation during labour were excluded.

RESULTS

There were 14 124 multiparous women who met the inclusion criteria; spontaneous labour is associated with an increased risk of OASIS at adjusted odds ratio (aOR) 1.46, P = 0.012. The overall rate of epidural use was 17%. Women with epidural use had significantly lower chances of sustaining OASIS in normal vaginal births and instrumental vaginal births. (1% vs 1.8%, aOR 0.49, P = 0.004). Epidural is associated with increased rates of prolonged second stage (8.5% vs 3.8%, P < 0.05), instrumental delivery (26.1% vs 4%, P < 0.05), and episiotomy use (23.8% vs 10.2%, P < 0.05).

CONCLUSION

The use of epidural analgesia in multiparous women is associated with a reduction in anal sphincter injuries.

Temporal trends in the incidence of and associations between the risk factors for obstetrical anal sphincter injuries

BACKGROUND

Obstetrical anal sphincter injuries are an important complication of vaginal deliveries that may result in short- and long-term pelvic floor morbidity and a diminished quality of life in young, healthy women. The prevalence of obstetrical anal sphincter injuries ranges from 0.1% to 8.7%. Over recent years, there seems to be a trend of increasing occurrence of obstetrical anal sphincter injuries worldwide. It is unclear why the rates are rising. Previous studies have examined the effect of different risk factors on the prevalence of obstetrical anal sphincter injuries. The change in the incidence of some risk factors for obstetrical anal sphincter injuries can partially explain the overall increase in obstetrical anal sphincter injuries. There is no previous study that explored the impact of the changes of individual risk factors over time on the risk for obstetrical anal sphincter injuries.

OBJECTIVE

The main aim of this study was to examine the temporal trends in the prevalence and odds ratio of the major risk factors known to be associated with obstetrical anal sphincter injuries in the period from 1988 to 2016.

STUDY DESIGN

This was a retrospective cohort study that included all women who underwent vaginal deliveries between 1988 and 2016 at a tertiary university medical center. The time intervals were divided into 4 periods (1988-1997, 1998-2007, 2008-2016, and the total time from 1988 to 2016) and the incidence of each risk factor was calculated for each time period. Correlation models and regression analysis were performed to examine the association between obstetrical anal sphincter injuries and the different risk factors over time. Furthermore, the trends in the odds ratios of the important risk factors over the time periods were evaluated using a multivariate regression analysis in which the primiparous women were separated from the multiparous women.

RESULTS

During the study period, there were 295,668 vaginal deliveries. Of these, 591 women were diagnosed with obstetrical anal sphincter injuries (0.2%). The significant risk factors for obstetrical anal sphincter injuries (P<.05) in the multivariable analysis were the following: primiparity, vaginal birth after cesarean delivery, vacuum extraction, and a birthweight of >4 kg. There was a significant (P<.05) increase in the incidence over the study period for the following risk factors: primiparity, vaginal birth after cesarean delivery, and vacuum extraction. No change was found in the incidence of the risk factor of a birthweight of >4 kg. In addition, we found a strengthening of the association between vaginal birth after cesarean delivery and macrosomia with obstetrical anal sphincter injuries, as opposed to a decline in the relative contribution of vacuum extraction to the overall risk for obstetrical anal sphincter injuries. Moreover, we found that obstetrical anal sphincter injuries among primiparous women increased 7-fold over the study period but was unchanged among multiparous women.

CONCLUSION

We have shown significant (P<.05) temporal trends in the incidence and odds ratio of some of the known risk factors for obstetrical anal sphincter injuries. A better understanding of the changes in the incidence and specific contribution of important risk factors for obstetrical anal sphincter injuries may explain, in part, the worldwide increase in the prevalence of this important and detrimental complication of vaginal birth.

The association between vacuum-assisted vaginal delivery and anal sphincter injury

INTRODUCTION

Vacuum-assisted vaginal delivery (VAVD) is considered a major risk factor for obstetric anal sphincter injuries (OASIS). However, it is difficult to estimate its true contribution to the occurrence of OASIS, as its performance may be confounded by other determinants. Therefore, we aimed to evaluate the association of VAVD with OASIS among primiparous women compared to SVD.

METHODS

A retrospective cohort study including all primiparous women who vaginally delivered a cephalic singleton gestation during the years 2011 to 2020. As VAVDs were not performed before 34 gestational weeks, we capped the cohort at this gestational age. Women were allocated into two groups: VAVDs and spontaneous vaginal deliveries (SVD). We compared women with OASIS to those without and performed a multivariate analysis including factors that were found significant in the univariate analysis. We further divided the whole cohort into different subcategories. The primary outcome was the rate of OASIS in VAVD compared to SVD.

RESULTS

Overall, 23,272 primiparous vaginal deliveries were available for evaluation. Of these, 3595 delivered by VAVD and 19,677 delivered spontaneously. OASIS occurred in 421 (1.8%) of the deliveries. OASIS were more common in VAVDs than in SVDs [83 (2.3%) vs. 338 (1.7%), respectively, OR (95% CI) 1.35 (1.06-1.72), p = 0.01]. After multivariate regression analysis, OASIS were not found to be independently associated with the mode of delivery [aOR 1.21 (95% CI) 0.88-1.68, P = 0.23]. In a categorical analysis of OASIS rates by risk factors and mode of delivery, VAVD was not associated with an increase in OASIS among women giving birth to neonates weighing > 3500 g compared to SVD [OR (95% CI) 1.02 (0.65-1.62), P = 0.90].

CONCLUSION

Among primiparous women VAVD did not increase the risk of OASIS compared to SVD.

Risk factors associated with severe perineal tears: A five-year study

OBJECTIVE

Our aim was to describe risk factors associated with 34DPT in operative and non-operative vaginal deliveries, over a five-year period.

STUDY DESIGN

This was a retrospective cohort study including 39,227 vaginal deliveries from 2013 to 2017 in a single French University Hospital. Annual characteristics of the analyzed population were recorded. Univariate logistic regression was used to evaluate the association between these characteristics and 34DPT. Multivariate analysis was used to identify combinations of risk factors associated with instrumental delivery.

RESULTS

The rate of perineal tears was constantly rising but rate of 34DPT was stable, ranging between 0.8 and 1.4% over the study period. Cesarean section rate was stable between 18.8% and 19.6%. Rate of diabetes, preeclampsia and obesity (BMI < 40) was increasing and episiotomy rate decreasing (from 19.8% to 11.8%). Operative deliveries rate remained stable between 11 and 12.8%. Multivariate regression showed that gestational age over 39 weeks (aOR 1.18, 95% CI [1.02; 1.35]), birth weight over 3500 g (aOR 1.62, 95% CI [1.05; 2.49]) were associated with 34DPT in patients without operative vaginal deliveries but not episiotomy. Gestational age (aOR 1.71, 95% CI [1.18; 2.47]), episiotomy (aOR 0.55, 95% CI [0.38; 0.79]) and diabetes (aOR 1.73, 95% CI [1.15; 2.61]) were associated with 34DPT among patients with operative vaginal deliveries.

CONCLUSION

In a tertiary medical center model with low cesarean section rate, factors associated with 34DPT were different among patients with or without operative vaginal delivery. The question of the protective effect of mediolateral episiotomy against 34DPT in case of operative delivery deserves further investigations.

The role of fetal head circumference in the formation of obstetric anal sphincter injuries following vacuum deliveries among primiparous women

PURPOSE

To evaluate the association of sonographic fetal head circumference (HC) with obstetric anal sphincter injury (OASIS) occurrence among primiparous women who underwent vacuum-assisted delivery (VAD).

METHODS

A retrospective study of all primiparous women who delivered at term by VAD between 2011 and 2019 and underwent ultrasound with fetal biometry within 1 week prior to delivery. Women who suffered OASIS were compared to women without OASIS.

RESULTS

Overall, 74 of 3222 (2.3%) primiparous women suffered an OASIS. As compared with control, women with OASIS were younger (median 28 vs. 30 years, p = 0.001), had higher BMI (median 28.2 vs. 26.9 kg/m², p = 0.03), and had a longer second stage of labor (median 190 vs. 168 min, p = 0.01). Fetal head circumference was larger in the OASIS group (mean 334 vs. 330 mm, p = 0.03), occiput posterior fetal head position was more prevalent (12 (16%) vs. 232 (7.4%), OR [95% CI]: 2.43 (1.29-4.57), p = 0.004), and the rate of mediolateral episiotomy performed was lower (58 (78.0%) vs. 2777 (88.2%), OR [95% CI]: 0.48 (0.27-0.85), p = 0.01). Multivariate regression modeling identified higher fetal HC (aOR [95% CI] 1.03 (1.001-1.06), p = 0.04) and occiput posterior (aOR [95% CI] 2.5 (1.16-5.71), p = 0.01) as independently positively associated with OASIS. Mediolateral episiotomy and maternal age were independently negatively associated with an OASIS (aOR [95% CI] 0.39 (0.18-0.85), p = 0.01); aOR [95% CI] 0.4 (0.17-0.60), p = 0.001).

CONCLUSIONS

Sonographic large fetal HC is associated with OASIS occurrence during VAD. The only modifiable predictor of OASIS detected was mediolateral episiotomy, found to be protective against OASIS.

Sonographic fetal head circumference and the risk of obstetric anal sphincter injury following vaginal delivery

INTRODUCTION

High birth weight is strongly associated with OASIS; nevertheless, it has not been determined which biometric characteristics most affect OASIS occurrence. We aimed to evaluate the association of estimated fetal head circumference with OASIS occurrence among primiparous women delivering by unassisted vaginal delivery.

METHODS

A retrospective study included all primiparous women who delivered at term by spontaneous vaginal delivery from 2011-2019. Women were allocated to two groups: (1) those who experienced OASIS and (2) those who did not experience OASIS. Risk factors for OASIS were analyzed.

RESULTS

Overall, 7646 women were included in the study cohort. Of those, 119/7646 (1.6%; 95% CI, 1.3-1.9%) experienced OASIS. Sonographic head circumference and birth weight did not vary between groups. Prolonged second stage was more common in the OASIS group [23 (19%) vs. 986 (13.3%), 1.58 OR (95% CI 1.003-2.51, p = 0.04)]. Absence of epidural analgesia was more common in the OASIS group [30 (25%) vs. 1197 (15.9%), 1.8 OR (95% CI 1.1-2.7, p = 0.006)]. On multivariate logistic regression analysis, the lack of epidural analgesia and duration of second stage of labor were both independently positively associated with OASIS [adjusted OR 2.67 (95% CI 1.55-4.62), p < 0.001, adjusted OR 1.23 (95% CI 1.11-1.43), p < 0.001, respectively)].

CONCLUSION

Sonographic head circumference and birth weight are not associated with OASIS occurrence among primiparous women delivering by an unassisted vaginal delivery. Prolonged second stage and the use of epidural analgesia are modifiable risk factors among these women.

What's new in obstetric anesthesia in 2018?

The Gerard W. Ostheimer Lecture presented at the annual meeting of the Society of Obstetric Anesthesia and Perinatology (SOAP) is a one-year summary of the literature published in domains of interest to anesthesiologists who manage and care for obstetric patients. One individual is asked to review the literature and present the lecture. This manuscript summarizes aspects of the Gerard W. Ostheimer Lecture presented at the 2019 SOAP meeting; the relevant literature from 2018 was summarized. The topics included in this review are maternal morbidity, antibiotic prophylaxis, anaphylaxis, the Lancet series on increasing cesarean delivery rates, the Robson Ten-Group Classification System, pelvic floor disorders, timing of delivery in nulliparous women, placenta accreta disorders, anesthesia for cesarean delivery, labor analgesia (including parturients with thrombocytopenia and tattoos, and epidural maintenance with the programmed intermittent epidural bolus technique), ultrasound use in obstetric anesthesia, and drugs in pregnancy.

Does epidural anesthesia influence pelvic floor muscle endurance and strength and the prevalence of urinary incontinence 6 weeks postpartum?

INTRODUCTION AND HYPOTHESIS

With the increasingly extensive application of epidural analgesia, its effect on pelvic floor function outcomes has received growing attention. The aim of the study is to determine the possible effect of epidural analgesia on pelvic floor muscle (PFM) endurance and strength and the prevalence of urinary incontinence (UI) and stress urinary incontinence (SUI) at 6 weeks postpartum.

METHODS

This is a retrospective cohort study of 333 primiparous women after vaginal delivery. At 6 weeks postpartum, a vaginal balloon connected to a high-precision pressure transducer was used to measure PFM strength and endurance. SUI/UI was determined using the verified Chinese International Classification of Urinary Incontinence Short Form (ICIQ-UI-SF) questionnaire. Statistical analysis was performed using binary logistic regression and multiple linear regression analysis.

RESULTS

Women in the epidural analgesia group experienced longer first and second stages of labor (p < 0.05). There were no statistically significant differences in the rates of perineal lacerations, forceps assistance or episiotomy between women with or without epidural analgesia (p > 0.05). No statistically significant differences were found in PFM endurance (B: 0.933, 95% CI confidence interval: -1.413 to 3.278, p: 0.435) or PFM strength (B: 0.044, 95% CI: -3.204 to 3.291, p:0.979) between these two groups. In addition, the prevalence of UI (30.77% vs. 26.87%) and SUI (21.54% vs. 16.42%) in women with or without epidural analgesia was not statistically significant (p > 0.05).

CONCLUSIONS

PFM function and UI prevalence at 6 weeks postpartum are not significantly affected by epidural analgesia.

Comparison between different epidural analgesia modalities for labor

INTRODUCTION

In recent years new modalities of epidural analgesia maintenance (EA) have been introduced.

OBJECTIVE

The objective of this study is to compare different modalities of EA maintenance for childbirth relating the time of expulsive and dilatation, motor blockade and delivery instrumentation (caesarean section, sucker, forceps, eutocic delivery or non-instrumented delivery).

MATERIAL AND METHODS

Patients admitted for labor in the University Hospital Nuestra Señora de Candelaria between January 2013 and December 2015 were included. Independent modalities of EA, continuous infusion (CI), continuous infusion plus analgesia patient controlled epidural analgesia were determined as independent variables (CI+PCEA) and intermittent programmed epidural boluses plus patient controlled epidural analgesia (PIEB+PCEA).

RESULTS

There are no differences in expulsive time or dilation. There is a difference in the type of instrumentation, caesarean section, sucker, forceps, eutocic delivery or non-instrumented delivery (P>.05), with the percentage of eutocic deliveries in PIEB+PCEA of 66 versus 60 in CI and 65 in CI+PCEA. The percentage of caesarean sections was 23 in CI, in CI+PCEA and PIEB+PCEA of 17. CI increases by 27% the possibility of instrumented deliveries respect to PIEB+PCEA, there is no difference between CI+PCEA and PIEB+PCEA. The motor blockade at 60 and 90minutes reaches lower values with PIEB+PCEA with an average of 0 and a range of 0-1, compared to CI+PCEA 0 (0-4). Satisfaction with CI+PCEA ranges from 2-10 and with PIEB+PCEA 0-10.

CONCLUSION

It is possible to say that PIEB+PCEA is associated with higher frequency of non-instrumented deliveries. The possibility of instrumented deliveries increases with CI versus PIEB+PCEA. There is less motor block with PIEB+PCEA than with CI+PCEA. There are no differences in time of dilatation, expulsion, or patient satisfaction.

Epidural analgesia and its implications in the maternal health in a low parity comunity

Background

In regard to obstetrical analgesia management there are different results related to the use of epidural analgesia versus mechanical adverse outcomes at delivery.

Methods

Cohort study of 23,183 consecutive, term, singleton vaginal deliveries, including spontaneous and induced labours, at a single institution from January 2004 to June 2016 to determine the association between epidural analgesia and different mechanical complications affecting maternal health such as severe perineal tears (SPT), abnormal foetal head position at delivery, instrumental delivery and caesarean section (CS).

Multivariate logistic regression models were constructed to evaluate the risk factors of these mechanical complications with respect to possible cofounders.

Results

Epidural analgesia was used in 15,821 (68.24%) women. The logistic regression model showed a non-significant association between the use of epidural analgesia and SPT (odds ratio [OR], 078; 95% confidence interval [CI], 0.48–1.26; p = 0.310). Instrumental delivery and CSs were more frequently performed in cases than controls (p = < 0.001), with OR of 1.19 (95% CI: 1.10–1.29) for CS and with OR of 3.27 (95% CI: 2.93–4.61) for instrumental delivery. The abnormal foetal position head at delivery were significantly lower in the neonates delivered without epidural analgesia compared with those in which epidural analgesia was used (p < 0.001) with OR of 1.43 (95% CI:1.27–1.72).

Conclusions

Epidural analgesia is not associated with an increase of SPT, but it was an independent risk factor for instrumental delivery, CS and abnormal foetal head position at delivery.

Relation between Epidural Analgesia and severe perineal laceration in childbearing women in Catalonia

OBJECTIVE

Our objectives were to study the association between epidural analgesia and risk of severe perineal laceration (SPL), and identify additional risk factors for SPL. This multicentre study consisted of an analysis of data from the MidconBirth Phase I Database, on the use of EA and perineal results during childbirth. (World Health Organization, International Clinical Trials Registry Platform, 2016: http://apps.who.int/trialsearch/Trial2.aspx?TrialID=ISRCTN17833269).

METHODS

We conducted a prospective study of pregnant women at term between July 2016 and July 2017 in 30 public maternity hospitals in Catalonia, Spain. Inclusion criteria were an uncomplicated singleton pregnancy, in cephalic presentation and vaginal birth. Data was analysed separately for instrumental births and spontaneous vaginal births, as the former is more frequently associated with episiotomy and more perineal lacerations. Risk factors as well as protective factors in each cohort of women (instrumental and spontaneous vaginal birth), were identified. Multivariate logistic regression model was performed to study the association between epidural analgesia and SPL to identify potential confounders. Odds ratios (OR), using 95% confidence intervals (CI) were constructed.

FINDINGS

During the study period, 5497 eligible women gave birth, 77.46% of them received epidural analgesia. SPL occurred in 1.63% of births. The univariate analysis showed births with epidural analgesia had significantly higher rates of inductions, augmentation of labour, lithotomy position for birth and episiotomy. However, this association disappeared when the variable "type of vaginal birth" was introduced. In multivariate logistic regression, nulliparity was the major predictor for SPL (OR: 0.17; CI 95%: 0.08-0.34, p: 0.000).

KEY CONCLUSIONS

Epidural analgesia was not associated with SPL once confounding factors were included. Other interesting factors associated with SPL were identified.

IMPLICATIONS FOR PRACTICE

This paper identifies important practice areas which contribute to SPL and which have the potential to be rectified. It offers evidence on the role that EA plays on pelvic floor injuries and it adds to existing evidence about the disadvantages of using the lithotomy position for birth, especially in relation to SPL. It highlights the need for practice change in Catalonia from what can be considered a medical model of care to one more aligned with the midwifery philosophy of care through the development of clinical guidelines. It also signals the need to provide women with evidence base upon which to make informed choices on the use of EA, specifically in relation to SPL.

Risk and protective factors for obstetric anal sphincter injuries: A retrospective nationwide study

BACKGROUND

In view of the reported increase in obstetric anal sphincter injuries, the objective of this study was to evaluate the incidence of such injuries over time and the associated risk and protective factors.

METHODS

This was a retrospective cohort study from a national database of 168 137 primiparous women with term, singleton, cephalic, vaginal delivery between 2008 and 2014. The main outcome measure was obstetric anal sphincter injury. A multivariate regression model was used to identify risk and protective factors.

RESULTS

Age >19 years, birthweight >4000 g, and operative vaginal delivery were independent risk factors for obstetric anal sphincter injuries. Mediolateral episiotomy increased the risk for obstetric anal sphincter injuries in spontaneous vaginal birth (number needed to harm 333), whereas it was protective in vacuum delivery (number needed to treat 50). From 2008 to 2014, there was an increase in the rate of obstetric anal sphincter injuries (2.1% vs 3.1%, P < .01), vacuum deliveries (12.1% vs 12.8%, P < .01), and cesarean delivery after labor (17.1% vs 19.4%, P < .01), while forceps deliveries (0.4% vs 0.1%, P < .01) and episiotomy rate decreased (35.9% vs 26.4%, P < .01).

CONCLUSIONS

Episiotomy may be a risk or protective factor depending on the type of episiotomy and the clinical setting in which it is used. Our study supports a restrictive use of mediolateral episiotomy in spontaneous vaginal deliveries. In vacuum deliveries mediolateral episiotomy may help prevent obstetric anal sphincter injuries.

[Definition, epidemiology and risk factors of obstetric anal sphincter injuries: CNGOF Perineal Prevention and Protection in Obstetrics Guidelines]

OBJECTIVES

The aim of this review was to agree on a definition of the obstetric anal sphincter injuries (OASIS), to determine the prevalence and risk factors.

METHODS

A comprehensive review of the literature on the obstetric anal sphincter injuries (OASIS), establishment of levels of evidence (NP), and grades of recommendation according to the methodology of the recommendations for clinical practice.

RESULTS

To classify obstetric anal sphincter injuries (OASIS), we have used the WHO-RCOG classification, which lists 4 degrees of severity. To designate obstetric anal sphincter injuries, we have used the acronym OASIS, rather than the standard French terms of "complete perineum" and "complicated complete perineum". OASIS with only isolated involvement of the EAS (3a and 3b) appears to have a better functional prognosis than OASIS affecting the IAS or the anorectal mucosa (3c and 4) (LE3). The prevalence of women with ano-rectal symptoms increases with the severity of the OASIS (LE3). In the long term, 35-60% of women who had an OASIS have anal or fecal incontinence (LE3). The prevalence of an OASI in the general population is between 0.25 to 6%. The prevalence of OASIS in primiparous women is between 1.4 and 16% and thus, should be considered more important than among the multiparous women (0.4 to 2.7%). In women with a history of previous OASIS, the risk of occurrence is higher and varies between 5.1 and 10.7% following childbirth. The priority in this context remains the training of childbirth professionals (midwives and obstetricians) to detect these injuries in the delivery room, immediately after the birth. The training and awareness of these practitioners of OASIS diagnosis improves its detection in the delivery room (LE2). Professional experience is associated with better detection of OASIS (LE3) (4). Continuing professional education of obstetrics professionals in the diagnosis and repair of OASIS must be encouraged (Grade C). In the case of second-degree perineal tear, the use of ultrasound in the delivery room improves the diagnosis of OASIS (LE2). Ultrasound decreases the prevalence of symptoms of severe anal incontinence at 1 year (LE2). The diagnosis of OASIS is improved by the use of endo-anal ultrasonography in post-partum (72h-6weeks) (LE2). The principal factors associated with OASIS are nulliparity and instrumental (vaginal operative) delivery; the others are advanced maternal age, history of OASIS, macrosomia, midline episiotomy, posterior cephalic positions, and long labour (LE2). The presence of a perianal lesion (perianal fissure, or anorectal or rectovaginal fistula) is associated with an increased risk of 4th degree lacerations (LE3). Crohn's disease without perianal involvement is not associated with an excess risk of OASIS (LE3). For women with type III genital mutilation, deinfibulation before delivery is associated with a reduction in the risk of OASIS (LE3); in this situation, deinfibulation is recommended before delivery (grade C).

CONCLUSION

It is necessary to use a consensus definition of the OASIS to be able to better detect and treat them.

[Obstetrical anal sphincter injuries and vacuum-assisted delivery at term in primiparas]

OBJECTIVES

Operative Vaginal Delivery (OVD) is subject to a risk of perineal tears especially of Obstetrical Anal Sphincter Injuries (OASIS) that are associated with more complications and impaired quality of life. The main objective of this study was to compare the rate of OASIS in primipara at term with fetus in cephalic presentation depending on the type of delivery: OVD using vacuum extractor and spontaneous delivery.

METHODS

This is a single-center retrospective study between 01/01/2010 and 12/31/2014 including all primipara who delivered vaginally at term, a single and living fetus in cephalic presentation. Perineal lesions were classified according to the WHO classification. The primary endpoint was the proportion of OASIS.

RESULTS

3552 patients were included: 2496 spontaneous deliveries (SD) and 1056 OVD (29.72 %). There were twenty sphincter tears (0.56 %): 7 in SD group (0.28 %) and 13 in OVD (1.23 %), P<0.0001, OR=5.10 [2.00; 12.99]. Other risk factors associated with OASIS in univariable analysis were: maternal age (≥30 years), duration of expulsive efforts (≥20min) and a birth weight≥4000g.

CONCLUSION

In these patients, the risk of OASIS in case of AI increases by a factor of 5;10. The high rate of AI in these patients exposes them to a real risk of OASIS. However, the proportion of OASIS in this group remains lower than those reported in the literature and is barely higher than the national overall rate, despite a very restrictive policy of the use of episiotomy.

What women want? Results from a prospective multicenter study on women's preference about pain management during labour

OBJECTIVE

The aim of this study was to assess women preference about pain and duration of labour applying a standardized questionnaire.

STUDY DESIGN

A prospective multicentre large cohort study was carried out in two different University Hospitals. A standardized questionnaire was proposed before active labour and the day after delivery in order to investigate whether women preferred low pain intensity for a longer labour duration or greater pain intensity for a shorter labour duration. The studied population was divided and analysed in two groups according to Epidural Analgesia (EA) administration. A multivariable linear regression analysis was performed to assess which variables were able to influence the opinion about the pain perception after birth.

RESULTS

EA group showed an increased risk of episiotomy (p = 0.004), of longer duration of labour (Stage I, p < 0.001; Stage II, p = 0.002) and of oxytocin augmentation (P = 0.030). No statistical differences were found about the route of delivery between the two groups. Rates of pre-labour scores significantly differed from rates of post labour scores (p < 0.001). In the multivariable linear regression analysis, pre-labour score was directly related to post-labour score (p = 0.013). The EA was indirectly related to higher pain levels for a longer duration preference (p = 0.001), whereas oxytocic infusion in labour was directly related with preference for higher pain for a shorter duration (p = 0.011).

CONCLUSIONS

Patients' preferences about labour are focused on both pain relief and labour duration. The standardized questionnaire could be a useful tool to screen patients eligible for EA.

Neuraxial labor analgesia is not an independent predictor of perineal lacerations after vaginal delivery of patients with intrauterine fetal demise

INTRODUCTION

The role of neuraxial labor analgesia in perineal trauma following live births is controversial, and no studies have assessed the association in women delivering an intrauterine fetal demise. We evaluated the relationship between neuraxial labor analgesia and perineal laceration in these patients.

METHODS

This was a retrospective case-control study of women with a diagnosis of fetal death after 20weeks of gestation, a vaginal delivery, and an Apgar score of 0 at delivery, during the period from January 2007 through December 2015. The presence of a perineal laceration and its severity, graded from grade I to IV based on the 2014 American College of Obstetricians and Gynecologists guidelines, was recorded.

RESULTS

A total of 329/422 (78%) patients received neuraxial, and 93/422 (22%) non-neuraxial, labor analgesia. A perineal laceration occurred in 23% in the neuraxial versus 10% in the non-neuraxial analgesia group, a difference of 13% (95% CI of difference 4% to 20%, P=0.005). After adjusting for confounder bias, greater birthweight (OR 4.22, 95% CI 3.00 to 5.92, P<0.001) and lower parity (OR 0.44, 95% CI 0.24 to 0.82, P=0.009), but not neuraxial analgesia (OR 1.29, 95% CI 0.47 to 3.57, P=0.61) were independent predictors of perineal laceration. The maintenance concentration of bupivacaine did not affect the rate of perineal injury.

CONCLUSIONS

Neuraxial labor analgesia does not appear to be an independent risk for a perineal laceration in patients with intrauterine fetal demise. Our data suggests that the use of neuraxial analgesia should not raise concern about increased rates of perineal injury.

[Pain therapy during labour]

To date the gold standard of treating labour pain is regional analgesia by application of epidural analgesia. When offering epidural analgesia, the programmed intermittent epidural bolus (PIEB) is more effective in terms of pain reduction, less motor blocks and higher satisfaction of the parturient compared to continuous application via perfusor pump. An upcoming alternative to epidural analgesia is remifentanil, a short acting and potent opioid. Remifentanil, however, requires haemodynamic monitoring as cardiac and respiratory impairment has been described. Nitrous oxide has been used for decades in the Anglosphere but it is a greenhouse gas, and interactions with Vitamin B₁₂ are possible. Using novel extraction systems, nitrous oxide has become more attractive for treatment of the initial phase of labour pain in Central Europe. In order to provide the parturient with the best possible and with a tailored pain concept an interdisciplinary approach with obstetricians, midwives and anaesthesiologists is required.

Does midwife experience affect the rate of severe perineal tears?

BACKGROUND

Our aim was to study whether midwife experience affects the rate of severe perineal tears (3rd and 4th degree).

METHODS

A retrospective cohort study of all women with term vertex singleton pregnancies, who underwent normal vaginal deliveries, in a single tertiary hospital, between 2011 and 2015, was performed. Exclusion criteria were instrumental deliveries and stillbirth. All midwives used a "hands on" technique for protecting the perineum. The midwife experience at each delivery was calculated as the time interval between her first delivery and current delivery. A comparison was performed between deliveries in which midwife experience was less than 2 years (inexperienced), between 2 and 10 years (moderately experienced), and more than 10 years (highly experienced). A multivariate regression analysis was performed to assess the association between midwife experience and the incidence of severe perineal tears, after controlling for confounders.

RESULTS

Overall, 15 146 deliveries were included. Severe perineal tears were diagnosed in 51 (0.33%) deliveries. Women delivered by inexperienced midwives had a higher rate of severe perineal tears compared with women delivered by highly experienced midwives (0.5% vs 0.2%, respectively, P=.024). On multivariate regression analysis, midwife experience was independently associated with a lower rate of severe perineal tears, after controlling for confounding factors. Each additional year of experience was associated with a 4.7% decrease in the risk of severe perineal tears (adjusted OR 0.95 [95% CI 0.91-0.99, P=.03).

CONCLUSION

More experienced midwives had a lower rate of severe perineal tears, and may be preferred for managing deliveries of women at high risk for such tears.

Obstetric Anal Sphincter Injuries (OASIs) in Israel: A Review of the Incidence and Risk Factors

Obstetric anal sphincter injuries (OASIs) following vaginal deliveries are the main reason for subsequent development of anal incontinence in women. The diagnosis of such tears is crucial for treating and preventing such a grave sequela. The reported rate of OASIs in Israel was between 0.1% and 0.6%, out of all vaginal births, which is 10-fold lower than that reported in Europe and the United States. Structured hands-on training in repair of OASIs in seven medical centers in Israel significantly increased the detection rate of third-degree perineal tears. The implementation of such programs is crucial for increasing awareness and detection rates of OASIs following vaginal deliveries.

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.

Predicting obstetric anal sphincter injuries in a modern obstetric population

BACKGROUND

Perineal lacerations are common at the time of vaginal delivery and may predispose patients to long-term pelvic floor disorders, such as urinary incontinence and pelvic organ prolapse. Obstetric anal sphincter injuries, which are the most severe form of perineal lacerations, result in disruption of the anal sphincter and, in some cases, the rectal mucosa during vaginal delivery. Long-term morbidity, including pain, pelvic floor disorders, fecal incontinence, and predisposition to recurrent injury at subsequent delivery may result. Despite several studies that have reported risk factors for obstetric anal sphincter injuries, no accurate risk prediction models have been developed.

OBJECTIVE

The purpose of this study was to identify risk factors and develop prediction models for perineal lacerations and obstetric anal sphincter injuries.

STUDY DESIGN

This was a nested case control study within a retrospective cohort of consecutive term vaginal deliveries at 1 tertiary care facility from 2004-2008. Cases were patients with any perineal laceration that had been sustained during vaginal delivery; control subjects had no lacerations of any severity. Secondary analyses investigated obstetric anal sphincter injury (3rd- to 4(th)-degree laceration) vs no obstetric anal sphincter injury (0 to 2(nd)-degree laceration). Baseline characteristics were compared between groups with the use of the chi-square and Student t test. Adjusted odds ratios and 95% confidence intervals were calculated with the use of multivariable logistic regression. Prediction models were created and model performance was estimated with receiver-operator characteristic curve analysis. Receiver-operator characteristic curves were validated internally with the use of the bootstrap method to correct for bias within the model.

RESULTS

Of the 5569 term vaginal deliveries that were recorded during the study period, complete laceration data were available in 5524 deliveries. There were 3382 perineal lacerations and 249 (4.5%) obstetric anal sphincter injuries. After adjusted analysis, significant predictors for laceration included nulliparity, non-black race, longer second stage, nonsmoking status, higher infant birthweight, and operative delivery. Private health insurance, labor induction, pushing duration, and regional anesthesia were not statistically significant in adjusted analyses. Significant risk factors for obstetric anal sphincter injury were similar to predictors for any laceration; nulliparity and operative vaginal delivery had the highest predictive value. Area under the curve for the predictive ability of the models was 0.70 for overall perineal laceration, and 0.83 for obstetric anal sphincter injury. When limited to primiparous patients, 1996 term vaginal deliveries were recorded. One hundred ninety-two women sustained an obstetric anal sphincter injury; 1796 women did not. After adjusted analysis, significant predictors for laceration included non-black race, age, obesity, and nonsmoking status. In secondary analyses, significant predictors for obstetric anal sphincter injury included non-black race, nonsmoking status, longer duration of pushing, operative vaginal delivery, and infant birthweight. Area under the curve for the predictive ability of the models was 0.60 for any laceration and 0.77 for obstetric anal sphincter injury.

CONCLUSIONS

Significant risk factors for sustaining any laceration and obstetric anal sphincter injury during vaginal deliveries were identified. These results will help identify clinically at-risk patients and assist providers in counseling patients about modifications to decrease these risks.

Episiotomy - risk factors and outcomes. J Matern Fetal Neonatal Med 2016;30:251-256. [PMID: 27018243 DOI: 10.3109/14767058.2016.1169527]

OBJECTIVE

To identify risk factors for mediolateral episiotomy, and evaluate the risk of obstetrical anal sphincter injury (OASI) among women with an episiotomy.

METHODS

A retrospective cohort study of all singletons vaginal deliveries at term between 2007 and 2014. Spontaneous and operative vaginal deliveries were compared separately, as well as nulliparous and multiparous women.

RESULTS

Overall, 41,347 women were included in the spontaneous vaginal delivery group: 12,585 (30.4%) nulliparous and 28,762 (69.6%) multiparous women. Risk factors for episiotomy (nulliparous) were maternal age (aOR 0.98), gestational age (GA, aOR 1.07), regional analgesia (RA, aOR 1.18), labor induction (aOR 1.17), meconium (aOR 1.37) and birth weight (BW, aOR 1.04). Episiotomy was associated with PPH (aOR 1.49). Among multiparous, risk factors were maternal age (aOR 1.04), previous vaginal delivery (aOR 0.38), GA (aOR 1.06), RA (aOR 1.22), meconium (aOR 1.22) and BW (aOR 1.05). Episiotomy was associated with 3rd degree perineal tear (aOR 2.26, 95% CI 1.03-4.97). Only birth weight (nulliparous) and previous vaginal deliveries (multiparous) were contributors for episiotomy in the OVD group.

CONCLUSION

Several risk factors for mediolateral episiotomy exist. Episiotomy does not protect nulliparous women, and may be associated with an increased risk for multiparous, for OASI. Therefore, the practice of routine episiotomy should be abandoned, and the practice of selective episiotomy reconsidered.