Sphincter Injury Research Articles

Perinatal outcome of fetuses predicted to be large-for-gestational age on universal third-trimester ultrasound in non-diabetic pregnancy.

To describe the perinatal outcome of fetuses predicted to be large-for-gestational age (LGA) on universal third-trimester ultrasound in non-diabetic pregnancies of women attempting vaginal delivery. This was a prospective population-based cohort study of patients from a single tertiary maternity unit in the UK offering universal third-trimester ultrasound and practicing expectant management of suspected LGA until 41-42 weeks. All women with a singleton pregnancy and an estimated due date between January 2014 and September 2019 were included. Women delivering before 37 weeks, those having a planned Cesarean delivery, those with pre-existing or gestational diabetes, those with fetal abnormalities and those who did not undergo a third-trimester scan were excluded from the assessment of perinatal outcome of cases with LGA predicted on ultrasound after implementation of the universal scan period. Association of LGA on universal third-trimester ultrasound screening and perinatal adverse outcome was assessed, with the exposures of interest being estimated fetal weight (EFW) at the 90th -95th , > 95th and > 99th percentile. The reference group was composed of fetuses with EFW at the 30th -70th percentile. Analysis was performed using multivariate logistic regression. The evaluated adverse perinatal outcomes included a composite outcome of admission to neonatal intensive care unit, Apgar score < 7 at 5 min and arterial cord pH < 7.1 (CAO1) and a composite outcome of stillbirth, neonatal death and hypoxic ischemic encephalopathy (CAO2). Secondary maternal outcomes were induction of labor, mode of delivery, postpartum hemorrhage, shoulder dystocia and obstetric anal sphincter injury. Cases with EFW > 95th percentile on universal third-trimester scan were at increased risk of CAO1 (adjusted odds ratio (aOR), 2.18 (95% CI, 1.69-2.80)) and CAO2 (aOR, 2.58 (95% CI, 1.05-6.34)). Cases with EFW at the 90th -95th percentile had a less pronounced increase in the risk of CAO1 (aOR, 1.35 (95% CI, 1.02-1.78)) and were not at increased risk of CAO2. All pregnancies with a fetus predicted to be LGA were at increased risk of all of the evaluated secondary maternal outcomes except for obstetric anal sphincter injury. The risk of adverse maternal outcome was typically higher with increasing EFW. Post-hoc exploration of data suggested that shoulder dystocia had a limited contribution to composite adverse perinatal outcomes in LGA cases (population attributable fraction of 10.8% for CAO1 and 29.1% for CAO2). Cases with EFW > 95th percentile are at increased risk of severe adverse perinatal outcome, such as death and hypoxic ischemic encephalopathy. These findings should aid antenatal counseling regarding the associated risk and delivery options. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Investigation of Expanded Human Adipose-derived Stem Cell Dosage and Timing for Improved Defecation Function.

Although certain treatment options exist for intestinal incontinence, none are curative. Adipose-derived stem cells (ADSCs) have emerged as promising therapeutic agents, but most preclinical studies of their effectiveness for anal function have used autologous or allogeneic ADSCs. In this study, the effectiveness, timing of administration, and required dosage of human ADSCs were investigated for clinical application. A 10-mm balloon catheter was used to induce anal sphincter injury in immunodeficient mice in the following experimental groups (n=4 per group): ADSC (injected ADSCs after injury), PBS (injected phosphate-buffered saline after injury), and control (uninjured). The effects of different timing (immediately after injection and 30 days following injury) and number of human ADSCs administered was compared among groups based on defecation status and pathological evaluation. In terms of defecation status, groups receiving ≥1×104 human ADSCs after injection showed improvement. Pathological images showed that compared to the PBS group, the thinnest part of the sphincter was thicker for animals that received ≥1×104 human ADSCs, and fibrosis of the sphincter was notable in those treated with 1×103 human ADSCs or PBS. Furthermore, defecation status was improved by administration of human ADSCs, not only immediately after injury, but also at 30 days following injury. Human ADSC administration in a mouse model of anal sphincter injury was effective. Injection of ≥1×104 human ADSCs was the amount necessary to improve defecation status, an effect detected in both the acute and chronic phases.

Research progress on the application of Chinese herbal medicine in anal fistula surgery.

Anal fistula is a rapidly developing anorectal disease that can lead to anal dysfunction if left untreated. Minimally invasive surgery is an important treatment option for anal fistula, as it can reduce the risk of anal sphincter injury and protect anal function. However, postoperative complications such as infection, pain, bleeding, edema, and fat liquefaction can occur, resulting in slow wound healing thus negatively impacting the patient's quality of life. Recent studies have shown that Chinese herbal therapy has distinct pharmacological effects and is more effective in treating postoperative complications in anal fistula patients compared to conventional drug therapy. It not only promotes wound healing but also reduces the occurrence of complications. Chinese herbs can also modulate relevant signaling pathways such as PI3K/Akt, HIF-1, and TGF-β/Smad to enhance the wound healing process. Various methods of Chinese herbal medicine (CHM) have been used to treat post-anal fistula operation wounds, including traditional Chinese medicine (TCM) sitz baths, external application of TCM, internal administration of TCM, anal absorption, and acupuncture, all of which have shown promising therapeutic effects in clinical practice. This article aims to review the theory and clinical application of CHM in anal fistula surgery in recent years and provide valuable references for its treatment.

Differences in rates of severe perineal trauma between midwife-led and obstetrician-led care in the Netherlands: A nationwide cohort study

ObjectiveTo investigate trends and rates of severe perineal trauma (SPT), also known as obstetric anal sphincter injury (OASI), between midwife-led and obstetrician-led care in the Netherlands, and factors associated with SPT. MethodsThis nationwide cohort study included registry data from 2000 to 2019 (n = 2,169,950) of spontaneous vaginal births of term, live, cephalic, single infants, without a (previous) caesarean section or assisted vaginal birth.First, trends of SPT and episiotomy were shown. Second, differences in SPT rates between midwife- and obstetrician-led care were assessed. Third, associations of care factors with SPT were examined. Multivariable logistic regression analyses were used to determine which factors were important in the associations. All outcomes were stratified for parity. ResultsOver time, the SPT incidence increased mainly in midwife-led care and episiotomy rates decreased. Compared to midwife-led care, SPT rates were lower in obstetrician-led care among primiparous women (aOR 0.78; 99 % CI 0.74–0.81) and comparable among multiparous women (aOR 1.04; 99 % CI 0.99–1.10). Among women without epidural analgesia, these differences were smaller for primiparous women (aOR 0.88; 99 % CI 0.84–0.92), but the SPT rate was higher in obstetrician-led care among multiparous women (aOR 1.09; 99 % CI 1.03–1.15). Among women without shoulder dystocia, induction, augmentation, and pain medication, SPT rates were comparable among primiparous women, but higher among multiparous women in obstetrician-led care. In midwife-led care, SPT occurred more often among hospital versus home births. In obstetrician-led care, lower SPT incidences were found among births with epidural analgesia and for multiparous women with induction or augmentation. ConclusionsAmong spontaneous vaginal births, induction, augmentation, and epidural analgesia in obstetrician-led care may be an explanatory factor for the higher incidence of SPT among primiparous women in midwife-led care. More research is needed to explain differences in SPT rates and to understand how SPT can be prevented, while maintaining a high intact perineum rate.

56 Transperineal ultrasound-based algorithm advising women after obstetric anal sphincter injury regarding their subsequent delivery mode

56 Transperineal ultrasound-based algorithm advising women after obstetric anal sphincter injury regarding their subsequent delivery mode

Predicting Urinary Incontinence among Postpartum Women

Urinary incontinence (UI) is common during a pregnancy-puerperium period, with a prevalence of 18.6-75% during pregnancy and 6-31% during postpartum. This study aims to review several published studies on which risk factors impact the incidence of UI.The search was conducted on Pubmed®, Cochrane Library®, and Ovid®, resulted in 57, 30, and 11 studies, respectively. We included cross-sectional, cohort, or case-control studies related to this aim. The risk of bias within the study was assessed using the Cochrane and Forrest plot was analysed using Review Manager 5.3. On maternal characteristics, age less than 35 years (OR 0.49; 95% CI 0.35-0.67), primiparity (OR 0.29; 95% CI 0.22-0.38), and BMI &lt;25 kg/m2 (OR 0.67; 95% CI 0.55-0.83) were considered as protective factors. A low level of education (OR 2.16; 95% CI 1.69-2.77) increased the risk of UI, Meanwhile, they showed heterogeneity among studies (I2&gt;50%). On delivery methods, the most prone to UI was emergency caesarean section followed by instrumental vaginal deliveries, spontaneous vaginal deliveries, and caesarean section. Episiotomy, epidural analgesia, and obstetric anal sphincter injury (OASIS) were not associated with UI (p&gt;0.05). On neonatal parameters, head circumference &lt;35 cm has a protective effect on UI (OR 0.82; 95% CI 0.73-0.93; I2=0%). Methods of delivery and head circumference will affect postpartum UI according to p-value (p&lt;0.05) and homogeneity among studies (I2&lt;50%).

Three-Dimensional Transperineal Ultrasound Guiding Early Secondary Repair of Obstetric Anal Sphincter Injury in an Incontinent Patient without Suture Dehiscence.

We present the case of a 36-year-old primigravida who gave birth to a 3200 g baby by vacuum-assisted (Kiwi OmniCup™) operative vaginal delivery with mediolateral episiotomy. A "y"-shaped perineal tear with a grade IIIC obstetric anal sphincter injury (OASI) was diagnosed and repaired. Two days after delivery, in the absence of suture dehiscence, she started experiencing complete anal incontinence. A decision was made in association with a proctologic surgeon for an early secondary repair. Before surgery, a Three-dimensional transperineal ultrasound (TPUS) was performed. The exam revealed a major defect of the external anal sphincter at the 11 o'clock position. This allowed for the reopening of only a circumscribed area of the perineal suture and repair of the sphincters using the end-to-end technique. The symptoms regressed completely, and follow-up TPUS demonstrated the gradual wound healing process. Anal incontinence, secondary to obstetric anal sphincter injury (OASI), has a severe negative impact on women's quality of life. TPUS is an effective method to detect sphincter defects and monitor the healing process. This report investigates the feasibility of identifying the sphincter tear in an incontinent puerperal patient without suture dehiscence in order to target early secondary repair while minimizing its extent. TPUS has proven a safe and effective tool to guide early secondary repair of symptomatic OASI complications while minimizing the invasiveness of the procedure. Multidisciplinary management is crucial to ensure the adequate standard of care.

UK survey of colorectal surgeons on the management of acute obstetric anal sphincter injuries.

The role of colorectal surgeons in the management of acute obstetric anal sphincter injury (OASI) is an ongoing debate. Their expertise in operating in the anorectal region lends itself to assisting in OASI repair. The aim of this study was to establish the current involvement and recommended management of acute OASI by colorectal surgeons. An online survey of consultant colorectal surgeons was sent to members of the Pelvic Floor Society to assess current involvement in acute OASI management and repair. Forty completed surveys were collated and analysed. Sixty-five per cent of respondents had seen an acute OASI since being a consultant and 50% stated they were involved in the repair of OASI less than once per year. 37.5% felt that a de-functioning stoma was still necessary sometimes. Many agreed with current guidelines for OASI repair in terms of antibiotics, laxatives and follow-up. Colorectal surgeons have varied opinions on the management of OASI. We suggest that multidisciplinary training of obstetricians and colorectal surgeons could lead to more collaboration regarding the management of women with acute OASI.

Surgical treatment of fecal incontinence

This article describes the surgical treatment of fecal incontinence. There are many surgical methods for fecal incontinence, and each treatment has its own advantages and disadvantages and indications. The appropriate surgical procedure should be selected according to the patient's history, anatomical structure and severity of incontinence. Injectable bulking agents is suitable for passive fecal incontinence. Sphincteroplasty is suitable for patients with sphincter injury caused by vaginal delivery or surgical trauma. Sacral nerve stimulation and posterior tibial nerve stimulation are relatively conservative methods. Gracilomyoplasty, artificial anal sphincter or magnetic anal sphincter can be used in the treatment of refractory fecal incontinence, but with many complications. Colostomy is the ideal choice for patients who have failed to respond to conservative treatment and cannot undergo these procedures.

Anal sphincter injury by bullfighting trauma.

Anal sphincter injury by bullfighting trauma.

Prevention of obstetric anal sphincter injuries with perineal support and lateral episiotomy: A historical cohort study.

There are many risk factors for obstetric anal sphincter injury (OASIS) and the interaction between these risk factors is complex and understudied. The many observational studies that have shown a reduction of OASIS rates after implementation of perineal support have short follow-up time. We aimed to study the effect of integration of active perineal support and lateral episiotomy on OASIS rates over a 15-year period and to study interactions between risk factors known before delivery. We performed a historical cohort study over the periods 1999-2006 and 2007-2021 at Stavanger University Hospital, Norway. The main outcome was OASIS rates. Women without a previous cesarean section and a live singleton fetus in cephalic presentation at term were eligible. The department implemented in 2007 the Finnish concept of active perineal protection, which includes support of perineum, control of fetal expulsion, good communication with the mother and observation of perineal stretching. The practice of mediolateral episiotomy was replaced with lateral episiotomy when indicated. We analyzed the OASIS rates in groups with and without episiotomy stratified for delivery mode, fetal position at delivery and for parity, and adjusted for possible confounders (maternal age, gestational age, oxytocin augmentation and epidural analgesia). We observed a long-lasting reduction in OASIS rates from 4.9% to 1.9% and an increase in episiotomy rates from 14.4% to 21.8%. Lateral episiotomy was associated with lower OASIS rates in nulliparous women with instrumental vaginal deliveries and occiput anterior (OA) position; 3.4% vs 10.1% (OR 0.31; 95% CI: 0.24-0.40) and 6.1 vs 13.9% (OR 0.40; 95% CI: 0.19-0.82) in women with occiput posterior (OP) position. Lateral episiotomy was also associated with lower OASIS rates in nulliparous women with spontaneous deliveries and OA position; 2.1% vs 3.2% (OR 0.62; 95% CI: 0.49-0.80). The possible confounders had little confounding effects on the risk of OASIS in groups with and without episiotomy. We observed a long-lasting reduction in OASIS rates after implementation of preventive procedures. Lateral episiotomy was associated with lower OASIS rates in nulliparous women with an instrumental delivery. Special attention should be paid to deliveries with persistent OP position.

Episiotomy: Are Indian Obstetricians Getting the Angle Right?

BackgroundA mediolateral episiotomy is recommended when indicated at a 60° angle at crowning, to avoid obstetric anal sphincter injuries (OASIs) by episiotomies angled too close or distant to the anus. This study surveyed obstetricians in India regarding the recommended episiotomy angle and their ability to correctly draw the angle.MethodsWorkshops were conducted in India to share knowledge in the prevention and repair of OASIs. A questionnaire was distributed prior to the workshop. Participants were asked to describe the recommended episiotomy angle and to draw this on a paper replica of the perineum. The intra-class correlation coefficient (ICC) was calculated to assess the inter-rater reliability between the angle stated and drawn. A 2° difference was deemed acceptable. Standard errors of measurement (SEM) were calculated to measure the range of error of each measurement.ResultsOne hundred and forty doctors participated. 47.9% described the angle of an episiotomy to be 60°. Only 2.2% drew an angle of 60°, but 8.7% (n = 12) drew between 58 and 62°. Only 5.8% (n = 6) of doctors correctly drew the episiotomy angle they described. There was poor agreement ICC = 0.18 (− 0.01 to 0.36) with a SEM of ± 12.2°ConclusionsKnowledge surrounding the recommended episiotomy angle is lacking. Doctors are failing to estimate their desired episiotomy angle. This highlights the need for national guidelines, the creation and validation of structured training programmes to improve accuracy, or using fixed-angle devices such as the EPISCISSORS-60 or other proven measurement aids to minimise preventable harm due to human error.

Predelivery sonographic predictors of obstetric anal sphincter injury among nulliparous women.

Data available at admission to delivery of nulliparous has rarely been investigated for prediction of obstetric anal sphincter injury (OASI). The aim of the present study was to study risk factors for OASI in nulliparous based on information available at admission. A retrospective study of all nulliparous women undergoing labor, during March 2011 to January 2021 was performed. We compared women with OASI following delivery to those without by univariate and multivariable regression. A total of 30 262 deliveries were included and 4181 (13.4%) of those were delivered by an emergent cesarean delivery. OASI followed 453 (1.5%) deliveries. Women in the OASI group were younger 29 ± 4.4 versus 30 ± 4.8, P = 0.001. In a multivariable regression analysis, higher sonographic estimated fetal weight was positively associated with OASI occurrence (aOR, 95% CI: 1.13 [1.00-1.29]). Maternal age was inversely associated with OASI occurrence (adjusted odds ratio [aOR], 95% confidence interval [CI] 0.95 [0.92-0.97]). Sonographic fetal weight estimation is an independent risk factor for OASI occurrence that may be available at admission for delivery among nulliparous women.

Tags for Tears: The Obstetric Anal Sphincter Injury Hashtag Ontology Project.

Social media is a powerful outlet for the dissemination of health care information. Adoption of a hashtag ontology-a standardized list of terms-may help better organize information and improve access to educational materials for health care providers (HCPs) and patients. The primary objective was to create a hashtag ontology specific to obstetric anal sphincter injuries (OASIS) based on Twitter usage. Secondary objectives included (1) performing a thematic analysis of OASIS-related tweet content and (2) reporting the type of users posting about OASIS. This study was an analysis of tweets related to OASIS posted between June 1, 2019, and June 1, 2022. Symplur Signals (a Twitter analytics software) (Symplur LLC, Los Angeles, CA) was used to identify relevant tweets based on predetermined search terms. Hashtags were reviewed by social media influencers to create a finalized ontology list. The top 100 tweets underwent thematic analysis and were grouped based on emergent themes. Types of users posting about OASIS were also analyzed. Symplur identified 660 tweets related to OASIS. The final ontology included the following 8 hashtags: #OASIS, #perinealtrauma, #birthtrauma, #3rddegreetear, #4thdegreetear, #episiotomy, #operativedelivery, and #postpartumbody. Major tweet content themes included education, self-promotion, patient experience, medical-legal, research, and opinions. Educational tweets surrounded prevention, risk factors, complications, and educational events related to OASIS and perineal trauma. Of the educational tweets, only 30% were posted by HCPs. This study created a standardized hashtag ontology related to OASIS. Less than one third of educational tweets were posted by HCPs.

A biomechanical perspective on perineal injuries during childbirth

Background and ObjectiveChildbirth trauma is a major health concern that affects millions of women worldwide. Severe degrees of perineal trauma, designated as obstetric anal sphincter injuries (OASIS), and levator ani muscle (LAM) injuries are associated with long-term morbidity. While significant research has been conducted on LAM avulsions, less attention has been given to perineal trauma and OASIS, which affect up to 90% and 11% of vaginal deliveries, respectively. Despite being widely discussed, childbirth trauma remains unpredictable. This work aims to enhance the modeling of the maternal musculature during childbirth, with a particular focus on understanding the mechanisms underlying the often overlooked perineal injuries. MethodsA geometrical model of the pelvic floor muscles (PFM) and perineum (including the perineal body, ischiocavernosus, bulbospongiosus, superficial and deep transverse perineal muscles) was created. The muscles were characterized by a transversely isotropic visco-hyperelastic constitutive model. Two simulations of vaginal delivery were conducted with the fetus in the vertex presentation and occipito-anterior position, with and without the perineum. ResultsThe simulation that considered the perineum exhibited higher stresses over an extended area of the PFM, which suggests that including additional structures can impact the obtained results. The maximum stretch of the urogenital hiatus was 2.94 and the maximum stress was 23.86 kPa. The perineal body reached a maximum stretch of 1.95, which was more pronounced near the urogenital hiatus, where perineal tears may occur. The external anal sphincter's transverse diameter decreased by 51% and the maximum principal stresses were observed in the area close to the perineal body, where OASIS can occur. ConclusionsThe present study emphasizes the importance of including most structures involved in vaginal delivery in its biomechanical analysis and represents another step further in the understanding of perineal injuries and OASIS. The superior region of the perineal body and its connection to the urogenital hiatus and anal sphincter have been identified as the most critical regions, highly susceptible to injury.

Reducing macrosomia-related birth complications in primigravid women: ultrasound- and magnetic resonance imaging–based models

Many complications increase with macrosomia, which is defined as birthweight of ≥4000 g. The ability to estimate when the fetus would exceed 4000 g could help to guide decisions surrounding the optimal timing of delivery. To the best of our knowledge, there is no available tool to perform this estimation independent of the currently available growth charts. This study aimed to develop ultrasound- and magnetic resonance imaging-based models to estimate at which gestational age the birthweight would exceed 4000 g, evaluate their predictive performance, and assess the effect of each model in reducing adverse outcomes in a prospectively collected cohort. This study was a subgroup analysis of women who were recruited for the estimation of fetal weight by ultrasound and magnetic resonance imaging at 36 0/7 to 36 6/7 weeks of gestation. Primigravid women who were eligible for normal vaginal delivery were selected. Multiparous patients, patients with preeclampsia spectrum, patients with elective cesarean delivery, and patients with contraindications for normal vaginal delivery were excluded. Of note, 2 linear models were built for the magnetic resonance imaging- and ultrasound-based models to predict a birthweight of ≥4000 g. Moreover, 2 formulas were created to predict the gestational age at which birthweight will reach 4000 g (predicted gestational age); one was based on the magnetic resonance imaging model, and the second one was based on the ultrasound model. This study compared the adverse birth outcomes, such as intrapartum cesarean delivery, operative vaginal delivery, anal sphincter injury, postpartum hemorrhage, shoulder dystocia, brachial plexus injury, Apgar score of <7 at 5 minutes of life, neonatal intensive care unit admission, and intracranial hemorrhage in the group of patients who delivered after the predicted gestational age according to the magnetic resonance imaging-based or the ultrasound-based models with those who delivered before the predicted gestational age by each model, respectively. Of 2378 patients, 732 (30.8%) were eligible for inclusion in the current study. The median gestational age at birth was 39.86 weeks of gestation (interquartile range, 39.00-40.57), the median birthweight was 3340 g (interquartile range, 3080-3650), and 63 patients (8.6%) had a birthweight of ≥4000 g. Prepregnancy body mass index, geographic origin, gestational age at birth, and fetal body volume were retained for the optimal magnetic resonance imaging-based model, whereas maternal age, gestational diabetes mellitus, diabetes mellitus type 1 or 2, geographic origin, fetal gender, gestational age at birth, and estimated fetal weight were retained for the optimal ultrasound-based model. The performance of the first model was significantly better than the second model (area under the curve: 0.98 vs 0.89, respectively; P<.001). The group of patients who delivered after the predicted gestational age by the first model (n=40) had a higher risk of cesarean delivery, postpartum hemorrhage, and shoulder dystocia (adjusted odds ratio: 3.15, 4.50, and 9.67, respectively) than the group who delivered before this limit. Similarly, the group who delivered after the predicted gestational age by the second model (n=25) had a higher risk of cesarean delivery and postpartum hemorrhage (adjusted odds ratio: 5.27 and 6.74, respectively) than the group who delivered before this limit. The clinical use of magnetic resonance imaging- and ultrasound-based models, which predict a gestational age at which birthweight will exceed 4000 g, may reduce macrosomia-related adverse outcomes in a primigravid population. The magnetic resonance imaging-based model is better for the identification of the highest-risk patients.

The association of maternal obesity and obstetric anal sphincter injuries at time of vaginal delivery

The risk of third- and fourth-degree perineal laceration after vaginal delivery in patients with obesity is relatively understudied and has mixed findings in existing literature. This study aimed to examine the association of maternal obesity and obstetric anal sphincter injuries at vaginal delivery. The Healthcare Cost and Utilization Project's National Inpatient Sample was retrospectively queried to examine 7,385,341 vaginal deliveries from January 2017 to December 2019. The exposure assignment was obesity status. The main outcomes were third- and fourth-degree perineal lacerations after vaginal delivery. Statistical analysis examining the exposure-outcome association included (1) inverse probability of treatment weighting with log-Poisson regression generalized linear model to account for prepregnant and pregnant confounders for the exposure and (2) multinomial regression model to account for delivery factors in the inverse probability of treatment weighting cohort. The secondary outcomes included (1) the temporal trends of fourth-degree laceration and its associated factors at cohort level and (2) risk factor patterns for fourth-degree laceration by constructing a classification tree model. In the inverse probability of treatment weighting cohort, patients with obesity were less likely to have fourth-degree lacerations and third-degree lacerations than patients without obesity (fourth-degree laceration: 2.3 vs 3.9 per 1000 vaginal deliveries, respectively; adjusted odds ratio, 0.62; 95% confidence interval, 0.56-0.69; third-degree laceration: 15.6 vs 20.1 per 1000 vaginal deliveries, respectively; adjusted odds ratio, 0.79; 95% confidence interval, 0.76-0.82). In contrast, in patients with obesity vs those without obesity, forceps delivery (54.7 vs 3.3 per 1000 vaginal deliveries, respectively; adjusted odds ratio, 17.73; 95% confidence interval, 16.17-19.44), vacuum-assisted delivery (19.8 vs 2.9 per 1000 vaginal deliveries, respectively; adjusted odds ratio, 5.18; 95% confidence interval, 4.85-5.53), episiotomy (19.2 vs 2.8 per 1000 vaginal deliveries, respectively; adjusted odds ratio, 3.95; 95% confidence interval, 3.71-4.20), and shoulder dystocia (17.8 vs 3.4 per 1000 vaginal deliveries, respectively; adjusted odds ratio, 2.60; 95% confidence interval, 2.29-2.94) were associated with more than a 2-fold increased risk of fourth-degree perineal laceration. Among the group with obesity, patients who had forceps delivery and shoulder dystocia had the highest incidence of fourth-degree laceration (105.3 per 1000 vaginal deliveries). Among the group without obesity, patients who had forceps delivery, shoulder dystocia, and macrosomia had the highest incidence of fourth-degree laceration (294.1 per 1000 vaginal deliveries). The incidence of fourth-degree perineal laceration decreased by 11.9% over time (P trend=.004); moreover, forceps delivery, vacuum-assisted delivery, and episiotomy decreased by 3.8%, 7.6%, and 29.5%, respectively (all, P trend<.05). This national-level analysis suggests that patients with obesity are less likely to have obstetric anal sphincter injuries at the time of vaginal delivery. Furthermore, this analysis confirms other known risk factors for fourth-degree laceration, such as forceps delivery, vacuum-assisted delivery, episiotomy, and shoulder dystocia. However, we noted a decreasing trend in fourth-degree lacerations, which may be due to evolving obstetrical practices.

EP34.04: The use of a new intrapartum 3D ultrasound technique to diagnose obstetric anal sphincter injuries

EP34.04: The use of a new intrapartum 3D ultrasound technique to diagnose obstetric anal sphincter injuries

Analysis of Obstetric Outcomes by Hospital Location, Volume, and Teaching Status Associated With Non–Medically Indicated Induction of Labor at 39 Weeks

ABSTRACT Previous research has shown that non–medically indicated induction of labor contributes to some favorable outcomes compared with expectant management in low-risk pregnancies. Cesarean birth rates have risen in recent years and represent a significant impact on long-term health of both mother and child. Research has connected these 2 phenomena, showing that non–medically indicated induction may reduce the overall likelihood of cesarean delivery, but it is not yet known how these outcomes are affected by hospital facility variables. This study was designed to examine outcome differences in women undergoing non–medically indicated induction at 39 weeks' gestation based on hospital characteristics such as obstetric volume, location, and teaching status. This study was designed as a retrospective cohort study, analyzing births between January 1, 2007, and December 31, 2011. Inclusion criteria were singleton, nonanomalous births at 39 weeks 0 days' gestation to 41 weeks 6 days' gestation among nulliparous mothers. Births with missing data on induction or hospital type were excluded, as well as births to pregnant individuals with comorbid conditions, placenta previa, breech presentation, stillbirths, and elective or planned cesarean delivery. The primary outcome was cesarean birth, and secondary outcomes included perinatal outcomes of severe maternal morbidity, chorioamnionitis, postpartum hemorrhage, operative vaginal birth, and obstetric anal sphincter injury, as well as neonatal outcomes of neonatal intensive care unit admission for more than 24 hours, respiratory distress syndrome, and shoulder dystocia. Analysis included 455,044 births, with 24,272 (5.3%) experiencing non–medically indicated induction of labor. Significant differences were found between non–medically indicated induction and expectant management when the sample was stratified by urban versus rural settings. Cesarean birth was significantly less likely among those who underwent non–medically indicated induction, with lower odds for rural (adjusted odds ratio [aOR], 0.68; 99% confidence interval [CI], 0.53–0.86) versus urban hospitals (aOR, 0.78; 99% CI, 0.74–0.81). For other outcomes assessed based on location, urban hospitals showed significantly lower odds of severe maternal morbidity (aOR, 0.78; 95% CI, 0.61–0.98), chorioamnionitis (aOR, 0.26; 99% CI, 0.22–0.30), postpartum hemorrhage (aOR, 0.73; 99% CI, 0.65–0.83), operative vaginal birth (aOR, 0.85; 99% CI, 0.79–0.90), and obstetric anal sphincter injury (aOR, 0.90; 99% CI, 0.82–0.98). Odds were also decreased for the neonatal outcomes of neonatal intensive care unit admission for more than 24 hours (aOR, 0.71; 99% CI, 0.66–0.77) and respiratory distress syndrome (aOR, 0.64; 99% CI, 0.57–0.71). In an analysis stratified by obstetric volume, odds of cesarean delivery were lower for those with non–medically indicated induction in both medium- and high-volume hospitals (aORs, 0.86 [99% CI, 0.78–0.94] and 0.73 [99% CI, 0.69–0.77], respectively). Stratified by hospital teaching status, significant differences were found in women who experienced non–medically indicated induction in the areas of race and ethnicity, age, BMI, and insurance type. Odds of cesarean delivery were again lower with induction, both in community and academic hospitals (aORs, 0.78 [99% CI, 0.74–0.81] and 0.67 [99% CI, 0.56–0.80], respectively). No significant differences between hospital types were observed. These findings support previous research showing that cesarean birth rates are lowered by non–medically indicated induction of labor at 39 weeks' gestation and show that previous findings hold across hospitals of different sizes, locations, and teaching status. With the increase in non–medically indicated induction, it is necessary for clinicians to optimize outcomes for mothers and infants using any evidence-based methods available. Further research could focus on variations between clinicians or hospital guidelines or policies. In addition, methods of induction have yet to be analyzed and tend to change over time; these could be opportunities for reanalysis to ensure the most benefit to patients in labor and delivery.

Predictive factors for obstetric anal sphincter injury in primiparous women: systematic review and meta-analysis.

The primary objective was to perform a systematic review of predictive factors for obstetric anal sphincter injury (OASI) occurrence at first vaginal delivery, with the diagnosis made by ultrasound (US-OASI). The secondary objective was to report on incidence rates of sonographic anal sphincter (AS) trauma, including trauma that was not clinically reported at childbirth, among the studies providing data for our primary objective. We conducted a systematic search of MEDLINE, EMBASE, Web of Science, CINAHL, The Cochrane Library and ClinicalTrials.gov databases. Both observational cohort studies and interventional trials were eligible for inclusion. Study eligibility was assessed independently by two authors. Random-effects meta-analyses were performed to pool effect estimates from studies reporting on similar predictive factors. Summary odds ratio (OR) or mean difference (MD) is reported with 95% CI. Heterogeneity was assessed using the I2 statistic. Methodological quality was assessed using the Quality in Prognosis Studies tool. A total of 2805 records were screened and 21 met the inclusion criteria (16 prospective cohort studies, three retrospective cohort studies and two interventional non-randomized trials). Increasing gestational age at delivery (MD, 0.34 (95% CI, 0.04-0.64) weeks), shorter antepartum perineal body length (MD, -0.60 (95% CI, -1.09 to -0.11) cm), labor augmentation (OR, 1.81 (95% CI, 1.21-2.71)), instrumental delivery (OR, 2.13 (95% CI, 1.13-4.01)), in particular forceps extraction (OR, 3.56 (95% CI, 1.31-9.67)), shoulder dystocia (OR, 12.07 (95% CI, 1.06-137.60)), episiotomy use (OR, 1.85 (95% CI, 1.11-3.06)) and shorter episiotomy length (MD, -0.40 (95% CI, -0.75 to -0.05) cm) were associated with US-OASI. When pooling incidence rates, 26% (95% CI, 20-32%) of women who had a first vaginal delivery had US-OASI (20 studies; I2 = 88%). In studies reporting on both clinical and US-OASI rates, 20% (95% CI, 14-28%) of women had AS trauma on ultrasound that was not reported clinically at childbirth (16 studies; I2 = 90%). No differences were found in maternal age, body mass index, weight, subpubic arch angle, induction of labor, epidural analgesia, episiotomy angle, duration of first/second/active-second stages of labor, vacuum extraction, neonatal birth weight or head circumference between cases with and those without US-OASI. Antenatal perineal massage and use of an intrapartum pelvic floor muscle dilator did not affect the odds of US-OASI. Most (81%) studies were judged to be at high risk of bias in at least one domain and only four (19%) studies had an overall low risk of bias. Given the ultrasound evidence of structural damage to the AS in 26% of women following a first vaginal delivery, clinicians should have a low threshold of suspicion for the condition. This systematic review identified several predictive factors for this. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.