Prevention and Management of Severe Obstetric Anal Sphincter Injuries (OASIs): a National Survey of Nurse- Midwives


Introduction and hypothesis

There are no data on midwives’ knowledge and management of obstetric anal sphincter injuries (OASIs) in the USA. We performed a cross-sectional national survey characterizing OASI practice by certified nurse midwives (CNMs), hypothesizing that few midwives personally repair OASIs and that there are gaps in CNM OASI training/education.


We emailed a REDCap internet-based survey to 6909 American College of Nurse Midwives members (ACNM). We analyzed responses from active clinicians performing at least one delivery per month, asking about OASI risks, prevention, repair, and management. We summarized descriptive data then evaluated OASI knowledge by patient and provider characteristics.


We received 1070 (15.5%) completed surveys, and 832 (77.8%) met the inclusion/exclusion criteria. Participants were similar to ACNM membership. Respondents most frequently identified prior OASI (87%) and nutrition (71%) as antepartum OASI risk factors and, less frequently, nulliparity (36%) and race (22%). Identified intrapartum risks included forceps delivery (94%) and midline episiotomy (88%). When obstetric laceration is suspected, 13.6% of respondents perform a rectal examination routinely. Only 15% of participants personally perform OASI repair. Overall, participants matched 64% of evidence-based answers. OASI education/training courses were attended by 30% of respondents, and 44% knew of OASI protocols within their group/institution. Of all factors evaluated, the percent of evidence-based responses was only different for respondent education/CME and protocols.


Quality initiatives regarding OASI prevention and management may improve care. Our data suggest OASI training for midwives may improve delivery care in the US. Further studies of other obstetric providers are needed.

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We acknowledge Andre Owens for his assistance implementing the invitations and Nicole Carlson, CNM, PhD, for her input on project design and the consensus process. We especially thank all the participants from ACNM without whom we could not have done this work.


This work was supported by the Rocky Vista University College of Osteopathic Medicine Intramural Research Grant (SD), the Department of Obstetrics and Gynecology (KJH), the Society of Family Planning Junior Investigator Career Grant SFPRF10-JI1 (MG), and the NIH/NCRR Colorado CTSI grant no. UL1 RR025780 (RedCap resource). Its contents are the authors’ sole responsibility and do not necessarily represent official UC Denver, Rocky Vista University, or NIH views.

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Correspondence to K. Joseph Hurt.

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Conference Presentations

ACOG Annual Meeting. San Diego, CA, May 2017



Table 5 Consensus panel evidence-based practices for OASI prevention and management
Table 6 Frequency of participants who matched consensus answer choices regarding ante- and intrapartum risk factors
Table 7 Frequency of participants who matched consensus answer choices regarding procedures performed at time of OASI repair and management approaches for patients with 3rd- or 4th-degree lacerations
Table 8 CME, protocols, and routine rectal examinations for those who personally repair OASIs
Table 9 Approach to OASI repair after primary or subsequent lacerations
Table 10 Participant response to performing episiotomies
Table 11 Participant free-text responses listing their routine OASI prevention techniquesa
Table 12 Knowledge and practice for OASIs by participant characteristics

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Diko, S., Guiahi, M., Nacht, A. et al. Prevention and Management of Severe Obstetric Anal Sphincter Injuries (OASIs): a National Survey of Nurse- Midwives. Int Urogynecol J 31, 591–604 (2020).

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  • Cross-sectional
  • Education
  • Midwifery
  • OASIs
  • Perineal trauma
  • Quality improvement