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

OBJECTIVE: To estimate the association between maternal origin and obstetric anal sphincter injury (OASI), and assess if associations differed by length of residence. DESIGN: Population-based cohort study. SETTING: The Medical Birth Registry of Norway. POPULATION: Primiparous women with vaginal livebirth of a singleton cephalic fetus between 2008 and 2017 (n = 188 658). METHODS: Multivariable logistic regression models estimated adjusted odds ratios (aORs) for OASI with 95% CI by maternal region of origin and birthplace. We stratified models on length of residence and paternal birthplace. MAIN OUTCOME MEASURES: OASI. RESULTS: Overall, 6373 cases of OASI were identified (3.4% of total cohort). Women from South Asia were most likely to experience OASI (6.2%; aOR 2.24, 95% CI 1.87-2.69), followed by those from Southeast Asia, East Asia & the Pacific (5.7%; 1.59, 1.37-1.83) and Sub-Saharan Africa (5.2%; 1.85, 1.55-2.20), compared with women originating from Norway. Among women born in the same region, those with short length of residence in Norway (0-4 years), showed the highest odds of OASI. Migrant women across most regions of origin had the lowest risk of OASI if they had a Norwegian partner. CONCLUSIONS: Primiparous women from Asian regions and Sub-Saharan Africa had up to two-fold risk of OASI, compared with women originating from Norway. Migrants with short residence and those with a foreign-born partner had higher risk of OASI, implying that some of the risk differential is due to sociocultural factors. Some migrants, especially new arrivals, may benefit from special attention during labour to reduce morbidity and achieve equitable outcomes. TWEETABLE ABSTRACT: Anal sphincter injury during birth is more common among Asian and Sub-Saharan migrants and particularly among recent arrivals.

Elective Labor Induction at 39 Weeks of Gestation Compared With Expectant Management: Factors Associated With Adverse Outcomes in Low-Risk Nulliparous Women.

OBJECTIVE: To evaluate characteristics associated with adverse outcomes in low-risk nulliparous women randomized to elective labor induction at 39 weeks of gestation or expectant management. METHODS: We conducted a secondary analysis of women randomized during the 38th week to induction at 39 weeks of gestation or expectant management. Deliveries before 39 weeks of gestation and those not adherent to study protocol or with fetal anomalies were excluded. A composite of adverse outcomes (perinatal death or severe neonatal complications), third- or fourth-degree lacerations, and postpartum hemorrhage were evaluated. Log binomial regression models estimated relative risks and 95% CIs for associations of outcomes with patient characteristics including randomly assigned treatment group. Interactions between patient characteristics and treatment group were tested. RESULTS: Of 6,096 women with outcome data, 5,007 (82.1%) met criteria for inclusion in this analysis. Frequency of the perinatal composite was 252 (5.0%), 166 (3.3%) for third- or fourth-degree perineal laceration, and 237 (4.7%) for postpartum hemorrhage. In multivariable analysis, intended labor induction at 39 weeks of gestation was associated with a reduced perinatal composite outcome (4.1% vs 6.0%; adjusted relative risk [aRR] 0.71; 95% CI 0.55-0.90), whereas increasing body mass index (BMI) was associated with an increased perinatal composite outcome (aRR 1.04/unit increase; 95% CI 1.02-1.05). Decreased risk of third- or fourth-degree perineal laceration was observed with increasing BMI (aRR 0.96/unit increase; 95% CI 0.93-0.98) and in Black women compared with White women (1.2% vs 3.9%; aRR 0.34; 95% CI 0.19-0.60). Increased risk of postpartum hemorrhage was observed in Hispanic women compared with White women (6.3% vs 4.0%; aRR 1.64; 95% CI 1.18-2.29). Patient characteristics associated with adverse outcomes were similar between treatment groups (P for interaction >.05). CONCLUSION: Compared with expectant management, intended induction at 39 weeks of gestation was associated with reduced risk of adverse perinatal outcome. Patient characteristics associated with adverse outcomes were few and similar between groups. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, NCT01990612.

Associations Between Maternal Obesity and Race, with Obstetric Anal Sphincter Injury: A Retrospective Cohort Study.

This retrospective cohort study examined associations between maternal body mass index (BMI), race, and obstetric anal sphincter injury (OASI) (3rd/4th degree perineal lacerations). Obstetric anal sphincter injury may lead to significant maternal morbidity, and a more thorough understanding of risk factors for this complication may guide providers in patient counseling and procedures such as episiotomy or operative vaginal delivery. Vaginal deliveries performed at Kapi'olani Medical Center for Women and Children from 2008-2015 were included. Maternal body mass index at delivery was used and OASIs identified through International Classification of Diseases codes. Demographic/clinical variables were summarized through descriptive statistics. Adjusted odds ratios were calculated using multiple logistic regression. Of the 25,594 deliveries included, 1,198 (4.7%) involved an OASI. OASI prevalence differed by BMI (P < .0001). The prevalence was highest in women with BMI < 30 kg/m2 (5.3%) and then decreased as BMI increased with women with BMI ≥ 50 demonstrating the lowest prevalence (1.7%). Compared to women with BMI < 30 kg/m2, women with BMI > 50 kg/m2 had a lower odds of OASI (OR 0.31 [95%CI 0.11 - 0.83]), which persisted after adjustment (aOR 0.28 [95%CI 0.08-0.96]). OASI also differed by race (P < .0001), with Native Hawaiian and other Pacific Islanders (NHOPI) demonstrating the lowest prevalence (3.0%) and Asians the highest (5.6%). After adjustment, compared to White women, NHOPI women had lower OASI prevalence that met the borderline of statistical significance (aOR 0.79 [95%CI 0.62-1.01]), while Asian women continued to demonstrate increased prevalence (aOR 1.50 [95% CI 1.22-1.85]). We conclude that obese women, including those with BMI ≥ 50 kg/m2, have lower OASI prevalence. Race is also a significant factor, with Asians almost double the prevalence of NHOPIs. These findings contribute to evidence-based, individualized patient counseling on OASI.

Racial/Ethnic Differences in Perineal Lacerations in a Diverse Urban Healthcare System.

OBJECTIVES: The aim of the study was o determine whether variations exist between races/ethnicities in perineal laceration at first vaginal delivery. METHODS: We assessed first vaginal deliveries greater than 35 weeks gestation, for a four-year period, in our diverse urban healthcare system. Predictor variable was race/ethnicity with outcome variable of none, first-, second-, third-, or fourth-degree perineal laceration. Race and ethnicity were self-reported and combined into one variable to facilitate analysis. We also collected data on other known risk factors for laceration to adjust our analysis accordingly. RESULTS: A total of 1179 charts met criteria. When comparing none, first-, or second-degree lacerations versus third or fourth degrees (obstetric anal sphincter injuries) race was not a significant factor. We also compared lacerations among the following three groups: none or first degree versus second degree versus obstetric anal sphincter injuries. In this case, Asian and white women were associated with an increasing trend of perineal lacerations as degree of severity increased (P < 0.0001), whereas black and Latina women were associated with a decreasing trend as severity increased (P < 0.0001). After adjusting for other significant variables, race was still significant (P = 0.02). CONCLUSIONS: With an urban diverse population, our study demonstrates an association between race/ethnicity and perineal lacerations. As degree of laceration increased, Asian and white women were noted to have more lacerations, and black and Latina women were noted to have fewer. Because perineal lacerations pose a significant risk to future pelvic floor health, the associated factors identified in this study may prove useful in counseling patients on future risk or in identifying the actual risk in underrepresented populations.

Epidural Analgesia and Any Vaginal Laceration.

BACKGROUND: Studies have shown increased incidence of severe vaginal lacerations (third and fourth degree) in women under the influence of epidural analgesia. This increase has been attributed to the increased the use of operative vaginal delivery (OVD), with attendant increased risk of laceration. Although mild and moderate vaginal lacerations requiring suturing are clinically significant, their relationship to epidural analgesia has not been extensively studied. OBJECTIVE: The purpose of this study is to examine relationships between epidural analgesia in laboring women and vaginal lacerations at delivery. Our research addresses the question: "Is epidural analgesia in labor associated with reduced likelihood of vaginal laceration at delivery, compared with delivery without epidural analgesia? In addition, is there a difference in vaginal laceration rates between an urban hospital staffed by obstetricians and a suburban hospital staffed mainly by family physicians?" STUDY DESIGN: For the purposes of our study we included mild and severe perineal lacerations (first through fourth degree). We included all-term singleton vaginal deliveries at Truman Medical Centers Hospital Hill and Lakewood during 2013. We conducted a retrospective chart review that included 2131 women. We examined the relationship of OVD to epidural and to laceration. Since the 2 hospitals had different characteristics, we also examined the relationship of location of delivery to laceration. We controlled for maternal age, birth weight, location of delivery, OVD, parity, and race. We examined these factors using a logistic regression analysis. RESULTS: After controlling for all factors mentioned above, epidural was negatively associated with laceration (odd ratio [OR], 0.886; 95% CL, 0.665, 0.991). Other factors negatively associated with laceration included black race, parity, and delivery at Truman Medical Center Lakewood (TMCLW). CONCLUSIONS: Patients who received epidural analgesia experienced fewer vaginal lacerations. There was no increase in OVD in patients who received epidural analgesia. Patients who delivered at a suburban hospital staffed by family medicine residents experienced fewer lacerations than those delivering at an urban hospital staffed by Obstetrics and Gynecology residents after controlling for race and other factors.

Are Asian American women at higher risk of severe perineal lacerations?

OBJECTIVE: To evaluate whether Asian race is an independent risk factor for severe perineal lacerations. METHODS: We performed a nationwide population-based retrospective cohort study examining the relationship between Asian race and severe perineal lacerations (third and fourth degree). The data were collected from the 2012 Healthcare Cost and Utilization Project National Inpatient Sample (HCUP-NIS). Characteristics of Asian American women were compared with those of non-Asian women. The primary outcome of interest was severe perineal lacerations. Multivariable logistic regression was used to refine the associations between Asian race and severe perineal lacerations while adjusting for confounding effects. Results were compared with previously published data using a pooled odds ratio. RESULTS: 2,270,044 Women with singleton vaginal deliveries were identified, and 120,452 (5.3%) were Asian. After adjusting for confounders, Asian women were more likely to experience severe perineal lacerations than any other racial group (3.5% versus 6.3%, adjusted odds ratio [aOR] 1.50, 99% CI 1.29-1.74, p < 0.0001). Analysis of literature indicated that Asian American women are 74% more likely to experience severe perineal lacerations (aOR 1.74, 99% CI 1.72-1.76, p < 0.0001) than non-Asians. CONCLUSION: Asian race is an independent risk factor for severe perineal lacerations in the United States.

Racial and ethnic disparities in maternal morbidity and obstetric care.

OBJECTIVE: To evaluate whether racial and ethnic disparities exist in obstetric care and adverse outcomes. METHODS: We analyzed data from a cohort of women who delivered at 25 hospitals across the United States over a 3-year period. Race and ethnicity was categorized as non-Hispanic white, non-Hispanic black, Hispanic, or Asian. Associations between race and ethnicity and severe postpartum hemorrhage, peripartum infection, and severe perineal laceration at spontaneous vaginal delivery as well as between race and ethnicity and obstetric care (eg, episiotomy) relevant to the adverse outcomes were estimated by univariable analysis and multivariable logistic regression. RESULTS: Of 115,502 studied women, 95% were classified by one of the race and ethnicity categories. Non-Hispanic white women were significantly less likely to experience severe postpartum hemorrhage (1.6% non-Hispanic white compared with 3.0% non-Hispanic black compared with 3.1% Hispanic compared with 2.2% Asian) and peripartum infection (4.1% non-Hispanic white compared with 4.9% non-Hispanic black compared with 6.4% Hispanic compared with 6.2% Asian) than others (P<.001 for both). Severe perineal laceration at spontaneous vaginal delivery was significantly more likely in Asian women (2.5% non-Hispanic white compared with 1.2% non-Hispanic black compared with 1.5% Hispanic compared with 5.5% Asian; P<.001). These disparities persisted in multivariable analysis. Many types of obstetric care examined also were significantly different according to race and ethnicity in both univariable and multivariable analysis. There were no significant interactions between race and ethnicity and hospital of delivery. CONCLUSION: Racial and ethnic disparities exist for multiple adverse obstetric outcomes and types of obstetric care and do not appear to be explained by differences in patient characteristics or by delivery hospital. LEVEL OF EVIDENCE: II.

Risk factors for anal sphincter tears in vacuum-assisted delivery.

OBJECTIVE: The aim of the present study was to describe the prevalence of anal sphincter tears (AST) in relation to obstetric management and technique during vacuum extraction deliveries (VE) (re: indications, the station of the fetal head at application of the cup, number of tractions, the length for the extraction, cup detachments, pain relief, episiotomy, fetal presentation, and experience of the operator) as well as maternal and infant anthropometrics. METHODS: Descriptive study. Data on six hundred vacuum extraction deliveries were consecutively collected from six different delivery units in Sweden. Each unit contributed with data on 100 deliveries. The final study population included 596 women who delivered by vacuum extraction. RESULTS: There was no correlation between the management of the vacuum extraction and risk for anal sphincter tear. Women from Africa had nearly a fourfold risk for anal sphincter tear during vacuum-assisted delivery compared with Swedish-born women (OR 3.82 CI 1.47-9.89). Compared with infants with birth weight less than 4000 g, birth weight above 4000 g was associated with increased risk of AST (OR 1.87 CI 1.06-3.28). CONCLUSIONS: In this study, the obstetric management in VE-assisted deliveries did not impact the risk of AST.

Risk factors for obstetric anal sphincter injuries and postpartum anal and urinary incontinence: a case-control trial.

INTRODUCTION AND HYPOTHESIS: Obstetric anal sphincter injuries (OASIS) cause serious maternal morbidity for mothers. A clearer understanding of aetiological factors is needed. We aimed to determine the risk factors for OASIS . METHODS: Birth details of 222 primiparous women sustaining OASIS were compared with 174 women who did not sustain OASIS (controls) to determine the relevant risk factors. The data underwent univariate analysis and logistic regression analysis. RESULTS: Asian or Indian ethnicity, operative vaginal birth (p = 0.00), persistent occipito-posterior position (p = 0.038) and rapid uncontrolled delivery of the head were identified as risk factors for OASIS. Pushing time, use of epidural, episiotomy and head circumference were not predictors of OASIS. CONCLUSIONS: Women with Asian or Indian ethnicity, operative vaginal birth, persistent occipito-posterior position and rapid uncontrolled delivery of the fetal head were likely to sustain OASIS. Awareness of these factors may help to minimise the incidence of OASIS.

Maternal Asian ethnicity and the risk of anal sphincter injury.

OBJECTIVE: To examine associations between maternal Asian ethnicity (South Asian and South East/East Asian) and anal sphincter injury. DESIGN: Retrospective cross-sectional study, comparing outcomes for Asian women with those of Australian and New Zealand women. SETTING: A large metropolitan maternity service in Victoria, Australia. POPULATION: Australian/New Zealand, South Asian and South East/East Asian women who had a singleton vaginal birth from 2006 to 2012. METHODS: The relation between maternal ethnicity and anal sphincter injury was assessed by logistic regression, adjusting for potential confounders. MAIN OUTCOME MEASURES: Anal sphincter injury was defined as a third or fourth degree tear (with or without episiotomy). RESULTS: Among 32,653 vaginal births there was a significant difference in the rate of anal sphincter injury by maternal region of birth (p < 0.001). After adjustment for confounders, nulliparous women born in South Asian and South East/East Asia were 2.6 (95% confidence interval 2.2-3.3; p < 0.001) and 2.1 (95% confidence interval 1.7-2.5; p < 0.001) times more likely to sustain an anal sphincter injury than Australian/New Zealand women, respectively. Parous women born in South Asian and South East/East Asia were 2.4 (95% confidence interval 1.8-3.2; p < 0.001) and 2.0 (95% confidence interval 1.5-2.7; p < 0.001) times more likely to sustain an anal sphincter injury than Australian/New Zealand women, respectively. CONCLUSION: There are ethnic differences in the rates of anal sphincter injury not fully explained by known risk factors for such trauma. This may have implications for care provision.

Racial/ethnic variations in perineal length and association with perineal lacerations: a prospective cohort study.

OBJECTIVE: To examine the association between race/ethnicity, perineal length and the risk of perineal laceration. METHODS: This is a prospective cohort study of a diverse group of women with singleton gestations in the third trimester of pregnancy. Perineal length was measured and mean values calculated for several racial/ethnic groups. Chi-squared analyses were used to examine rates of severe perineal laceration (third or fourth degree laceration) by race/ethnicity among women considered to have a short perineal length. Further, subgroup analyses were performed comparing nulliparas to multiparas. RESULTS: Among 344 study participants, there was no statistically significant difference in mean perineal length by race/ethnicity (White 4.0 ± 1.1 cm, African-American 3.7 ± 1.0 cm, Latina 4.1 ± 1.1 cm, Asian 3.8 ± 1.0 cm, and other/unknown 4.0 ± 0.9 cm). Considering parity, more multiparous Asian and African-American women had a short perineal length (20.7 and 23.5%, respectively, p = 0.05). Finally, the rate of severe perineal lacerations in our cohort was 2.6% overall, but was 8.2% among Asian women (p = 0.04). CONCLUSIONS: We did not find a relationship between short perineal length and risk of severe perineal laceration with vaginal delivery, or a difference in mean perineal length by maternal race/ethnicity. However, we did find that women of different racial/ethnic groups have varying rates of severe perineal laceration, with Asian women comprising the highest proportion.

Risk factors for severe perineal injury during childbirth: a case-control study of 60 consecutive cases.

AIM: The study aimed to evaluate the current risk factors for severe perineal tears in a single university-affiliated maternity hospital. METHOD: An obstetric database of 31 784 consecutive women who delivered from January 2007 to December 2009 was screened for cases of third-degree or fourth-degree perineal tears. Four controls, matched by time of delivery, were selected for each case of third- or fourth-degree perineal tear. Maternal and obstetric parameters were analyzed and compared between the study and control groups. RESULTS: Sixty women (0.25% of all vaginal deliveries) had a third-degree (53 women) or a fourth-degree (seven women) perineal tear. The control group comprised 240 matched vaginal deliveries without severe tears. Primiparity, younger maternal age, Asian ethnicity, longer duration of second stage of labour, vacuum-assisted delivery and heavier newborn birth weight were significantly more common among women who had third- or fourth-degree perineal tears. Of the variables that were found to be statistically significant in the univariate analysis, only primiparity (OR = 2.809, 95% CI: 1.336-5.905), vacuum delivery (OR = 10.104, 95% CI: 3.542-28.827) and heavier newborn birth weight (OR = 1.002, 95% CI: 1.001-1.003) were found to be statistically significant independent risk factors for severe perineal trauma. CONCLUSION: Identification of women at risk may facilitate the use, or avoidance, of certain obstetric interventions to minimize the occurrence of childbirth-associated perineal trauma.

Characteristics associated with severe perineal and cervical lacerations during vaginal delivery.

OBJECTIVE: To characterize potentially modifiable risk factors for third- or fourth-degree perineal lacerations and cervical lacerations in a contemporary U.S. obstetric practice. METHODS: The Consortium on Safe Labor collected electronic medical records from 19 hospitals within 12 institutions (228,668 deliveries from 2002 to 2008). Information on patient characteristics, prenatal complications, labor and delivery data, and maternal and neonatal outcomes were collected. Only women with successful vaginal deliveries of cephalic singletons at 34 weeks of gestation or later were included; we excluded data from sites lacking information about lacerations at delivery and deliveries complicated by shoulder dystocia; 87,267 and 71,170 women were analyzed for third- or fourth-degree and cervical lacerations, respectively. Multivariable logistic regressions were used to adjust for other factors. RESULTS: Third- or fourth-degree lacerations occurred in 2,516 women (2,223 nulliparous [5.8%], 293 [0.6%] multiparous) and cervical lacerations occurred in 536 women (324 nulliparous [1.1%], 212 multiparous [0.5%]). Risks for third- or fourth-degree lacerations included nulliparity (7.2-fold risk), being Asian or Pacific Islander, increasing birth weight, operative vaginal delivery, episiotomy, and longer second stage of labor. Increasing body mass index was associated with fewer lacerations. Risk factors for cervical lacerations included young maternal age, vacuum vaginal delivery, and oxytocin use among multiparous women, and cerclage regardless of parity. CONCLUSION: Our large cohort of women with severe obstetric lacerations reflects contemporary obstetric practices. Nulliparity and episiotomy use are important risk factors for third- or fourth-degree lacerations. Cerclage increases the risk for cervical lacerations. Many identified risk factors may not be modifiable.

Perineal length: norms in gravid women in the first stage of labour.

INTRODUCTION: The purpose of this study was to generate normative data for perineal length for Caucasian and Asian women in labour. METHODS: The distance from the posterior fourchette to the centre of the anal orifice was measured in 1,000 women in the first stage of labour. Data on ethnicity, body mass index, delivery mode and perineal trauma were collected prospectively. RESULTS: The mean perineal length in Caucasian women was 3.7 +/- 0.9 cm and in Asian women, 3.6 +/- 0.9 cm. Primigravid women with short perineum were more likely to have a third-degree perineal tear in labour (p = 0.03). CONCLUSION: This is the first paper to report normative data for perineal length in Caucasian and Asian women in labour. We found a negative correlation between perineal length and third-degree tear in primigravid women. These data may be useful in clinical practice to determine the risk of significant perineal tears in labour.

Postpartum anal sphincter lacerations in a population with minimal exposure to episiotomy and operative vaginal delivery.

This case-control study was designed to identify risk factors for anal sphincter lacerations (ASL) in a multicultural population where episiotomies and operative vaginal deliveries are rarely performed. Cases were subjects with ASL delivered between July 1997 and June 2003. Two controls were selected for each case matched for gestational age. Independent variables collected included age, race/ethnicity, parity, tobacco use, medical conditions, episiotomy, operative vaginal delivery, epidural use, and infant weight. One thousand and sixty-six subjects met the inclusion criteria. The risk of ASL increased with increasing maternal age (Odds ratio [OR] 1.09 per year, 95% confidence interval [CI] 1.06, 1.12) and increasing infant weight (OR 1.09 per 100 g, 95% CI 1.06, 1.13). Multiparity was protective (P1 vs P2 OR 0.19, 95% CI 0.13, 0.28, and > or =P3 vs P1 OR 0.04, 95% CI 0.02, 0.11). Hispanic and Native American women were at increased risk for ASL (OR 2.08, 95% CI 1.41, 3.09 and OR 1.92, 95% CI 1.07, 3.45, respectively).