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Abstract Background Obstetric anal sphincter injury (OASI) is a common and severe complication of vaginal delivery and may have short- and long-term consequences, including anal incontinence, sexual dysfunction and reduced quality of life. The rate of OASI varies substantially between studies and national birth statistics, and a recent meta-analysis concluded that there is a need to identify unrecognized risk factors. Our aim was therefore to explore both potential modifiable and non-modifiable risk factors for OASI. Methods We performed a case–control study in a single center maternity clinic in South-Eastern Norway. Data were extracted retrospectively from an institutional birth registry. The main outcome measure was the occurrence of the woman’s first-time 3rd or 4th degree perineal lesion (OASI) following singleton vaginal birth after 30 weeks’ gestation. For each woman with OASI the first subsequent vaginal singleton delivery matched for parity was elected as control. The study population included 421 women with OASI and 421 matched controls who gave birth during 1990–2002. Potential risk factors for OASI were assessed by conditional logistic regression analyses. Results The mean incidence of OASI was 3.4% of vaginal deliveries, but it increased from 1.9% to 5.8% during the study period. In the final multivariate regression model, higher maternal age and birthweight for primiparous women, and higher birthweight for the multiparous women, were the only non-modifiable variables associated with OASI. Amniotomy was the strongest modifiable risk factor for OASI in both primi- (odds ratio [OR] 4.84; 95% confidence interval [CI] 2.60–9.02) and multiparous (OR 3.76; 95% CI 1.45–9.76) women, followed by augmentation with oxytocin (primiparous: OR 1.63; 95% CI 1.08–2.46, multiparous: OR 3.70; 95% CI 1.79–7.67). Vacuum extraction and forceps delivery were only significant risk factors in primiparous women (vacuum: OR 1.91; 95% CI 1.03–3.57, forceps: OR 2.37; 95% CI 1.14–4.92), and episiotomy in multiparous women (OR 2.64; 95% CI 1.36–5.14). Conclusions Amniotomy may be an unrecognized independent modifiable risk factor for OASI and should be further investigated for its potential role in preventive strategies.

Abstract Background Obstetric anal sphincter injury (OASI) is a debilitating complication of vaginal delivery which has yet to receive ample attention in adolescents. The aim of this study was to describe risk for OASI in adolescent mothers compared to adults. We further attempted to compare risk factors for OASI between these two age groups. Methods We performed a retrospective cohort study between 2003 and 2019. Primiparous women who delivered vaginally, 21 years and younger were compared to women ages 26–35. Excluded were preterm, multifetal, non-vertex, cesarean deliveries as well as intrauterine fetal death. Rate of OASI as well as obstetric and labor characteristics of women with OASI, were compared between groups. Finally, risk factors were assessed for each group separately. Univariate and multivariate logistic regression model were performed. Results Final analysis was performed on 5113 nulliparous adolescents and 13,845 nulliparous in the 26–35 age group. Allocation to study groups was according to OASI – Sixty-seven adolescents (1.3%) had a 3rd or 4th degree perineal tear and were defined as the OASI group, while 5046 patients (98.7%) did not have such a tear. In the adult group, 199 out of 13,845 patients (1.4%) were diagnosed with OASI. Occurrence of OASI did not differ between groups (p = 0.510). Comparison of women with OASI in the adolescent group vs. adult group found differences with regard to operative vaginal delivery, (20.9% vs. 36.2%, respectively; p = 0.023) and meconium stained amniotic fluid (9.1% vs. 21.3%, respectively; p = 0.027). Following multivariate analysis the only parameter independently associated with OASI in the adolescent age group was head circumference ≥ 90th percentile with an adjusted odds ratio of 3.08 (CI 1.48–6.38, p = 0.003). In the adult group the similar analysis revealed operative vaginal delivery (OR = 2.44, CI 1.72–3.47, p

Abstract Background We aimed at developing a core outcome and variables of interest set to investigate the effects of mediolateral episiotomy on Obstetric Anal Sphincter Injury (OASI) during and after operative delivery in nulliparous women in a large-scale one-year observational French study including 15,000 women (INSTRUMODA). Methods A list of outcomes and variables of interest was suggested to obstetricians participating in the INSTRUMODA study using online questionnaires divided into 7 categories: the woman’s history and course of pregnancy, course of labor, modalities of operative delivery, episiotomy characteristics, immediate maternal morbidity, one-year maternal morbidity, immediate neonatal morbidity. We used a three-round DELPHI method to reach a consensus. In the first round, outcomes and variables considered as essential by 70% or more of obstetricians were included in the corpus whereas they were excluded when 70% rated them as “not important”. In the second round, non-consensual outcomes and variables were reassessed and excluded or definitively included if considered as “not important” or essential by 50% or more of the obstetricians. During the first round, obstetricians were invited to suggest new outcomes and/or variables that were then assessed in the second and third round. We used the same method to develop a core outcome and variables of interest set in a population of women in the community recruited via an association of patients. At the end of the procedure the core outcome and variables of interest sets were merged to provide the final core outcome set for the INSTRUMODA study. Results Fifty-three obstetricians and 16 women filled out questionnaires. After the 3 rounds of Delphi procedure in each population, 74 outcomes and variables were consensually reported by obstetricians and 92 by women in the community. By mixing these two consensual corpora we reported a final consensual list of 114 variables of interest and outcomes for both obstetricians and women. Conclusion We established a core outcome and variables of interest set among obstetricians and women in the community to investigate the association between mediolateral episiotomy and OASI during operative delivery. Trial registration The INSTRUMODA study was registered on https://clinicaltrials.gov on June 25, 2020 ( NCT04446780 ).

Abstract Background Obstetric anal sphincter injury (OASI) is one of the most severe obstetrical complications. Although risk factors for OASI have been identified, little is known about various parameters that can influence symptoms’ severity. The aim of this study is to explore whether obstetrical and epidemiological factors can have an effect on the severity of symptoms after OASI. Methods 11.483 deliveries between January 2010 and December 2014 were reviewed, and data from 88 women with OASI are presented. Results The only statistically significant differences between symptomatic and asymptomatic women were age (p = 0.02), body mass index (p = 0.04) and the use of forceps (p = 0.04). Women with more severe symptoms were more likely to have received oxytocin during the second stage of labor (p = 0.03) and had shorter delivery to follow-up interval (p = 0.008). Conclusions Modifiable factors such as use of forceps and oxytocin should be taken into consideration in clinical practice.

Abstract Background Third and fourth degree perineal tears, or obstetric anal sphincter injuries (OASI), sustained during childbirth can result in anal incontinence and psychosocial problems which require ongoing treatment. Within the English National Health System (NHS) reported rates of OASI have gradually increased. In response, a care bundle was developed incorporating four elements: 1) antenatal information to women, 2) manual perineal protection during all vaginal births, 3) episiotomy to be performed with a 60° mediolateral angle at crowning (when clinically indicated) and 4) perineal examination (including per rectum) after childbirth. Implementation of the OASI Care Bundle is aided by a skills development module and an awareness campaign. The project is a collaboration between two national professional bodies, an NHS hospital trust and an academic institution. Methods Implementation of the OASI Care Bundle will be evaluated using a stepped-wedge design. From January 2017 sixteen maternity units across England, Wales and Scotland will participate in the study over a 15-month period, with sequential roll-out of the intervention in four blocks (regions) of four units. The primary clinical outcome is OASI rate. Regression analysis will adjust for differences in organisational characteristics and obstetric risk factors in women who gave birth before and after implementation of the care bundle. Focus group discussions and in-depth interviews with clinicians will evaluate the feasibility of integrating the care bundle into routine practice. Interviews with women will explore the acceptability of the intervention. Discussion This protocol outlines the evaluation of our quality improvement project which aims to prevent OASI using a bundle of evidence-based interventions that are each widely used in practice. The OASI project aims to 1) standardise practice to prevent OASI in a way that is acceptable to clinicians and women and 2) identify the barriers and enablers associated with upscaling interventions within maternity units. If found to be effective, feasible and acceptable, the OASI Care Bundle will be shared with a range of audiences using the communication channels available to the professional bodies. Trial registration The OASI Project was retrospectively registered on the ISCTRN12143325 database date assigned 03/10/2017.

Abstract Background Obstetric anal sphincter injury (OASI) is a rare but serious outcome of vaginal birth. Based on concerns about the increasing number of women who commence childbearing later than previous generation, this study aimed at investigating age-related risk of OASI in women of different parity. Methods A population-based register study including 959,559 live singleton vaginal births recorded in the Swedish Medical Birth Register 1999 to 2011. In each parity group risks of OASI at age 25–29 years, 30–34 years, and ≥35 years compared with age

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.

Background: To identify the emotional, social and psychological consequences and recovery process of anal incontinence (AI) following obstetric anal sphincter injuries (OASIS) and explore if this can be identified as a recognisable syndrome with visual representation., Methods: A qualitative approach was adopted for this study. Data derived from case studies (n = 81) and interviews (n = 14) with women with AI after OASIS was used to identify the emotional, social and psychological consequences of AI after OASIS. Keywords and synonyms were extracted and the power of these statements displayed as a 'word picture'. The validity and authenticity of the word picture was then assessed by: a questionnaire sent to a group of mothers who had experienced this condition (n = 16); a focus group attended by mothers (n = 14) and supported by health professionals (n = 6) and via interviews with health professionals (n = 12) who were involved with helping mothers with AI following OASIS., Results: Women with AI resulting from OASIS have a specific syndrome - the 'OASIS Syndrome' - which we have uniquely visualised as a 'word picture'. They feel unclean which results in dignity loss, psychosexual morbidity, isolation, embarrassment, guilt, fear, grief, feeling low, anxiety, loss of confidence, a feeling of having been mutilated and a compromised role as a mother. Coping relies on repetitive washing (which may become a ritual), planning daily activities around toiletry needs, sharing, family support, employment if possible and attention to the baby. Recovery and healing is through care of the child and hope generated by love within the family., Conclusions: This study has identified a previously unrecognised 'OASIS Syndrome' and, by way of a new and unique 'word picture', revealed a hidden condition. There should be greater awareness by the public and profession about the 'OASIS Syndrome' and a mechanism for early identification of the condition and referral for management. This, if successful, would overcome the barrier of silence which surrounds this currently unspoken taboo.