Can the risk of obstetric anal sphincter injuries (OASIs) be predicted using a risk-scoring system?

BMC Research Notes

Ranee Thakar¹  Abdul H Sultan¹  Andrew D Beggs²  Karl C McPherson¹ 

[1] Department of Obstetrics & Gynaecology, Croydon University Hospital, 530 London Road, Croydon, CR7 7YE London, UK;Academic Department of Surgery, School of Cancer Sciences, Birmingham, UK

关键词: Third and fourth degree tears;    Risk factors;    Perineal trauma;    Anal sphincter;   

Others  :  1131827
DOI  :  10.1186/1756-0500-7-471

 received in 2014-01-27, accepted in 2014-07-21,  发布年份 2014

【 摘 要 】

Background

Perineal trauma involving the anal sphincter is an important complication of vaginal delivery. Prediction of anal sphincter injuries may improve the prevention of anal sphincter injuries. Our aim was to construct a risk scoring model to assist in both prediction and prevention of Obstetric Anal Sphincter Injuries (OASIs). We carried out an analysis of factors involved with OASIs, and tested the constructed model on new patient data.

Methods

Data on all vaginal deliveries over a 5 year period (2004–2008) was obtained from the electronic maternity record system of one institution in the UK. All risk factors were analysed using logistic regression analysis. Odds ratios for independent variables were then used to construct a risk scoring algorithm. This algorithm was then tested on subsequent vaginal deliveries from the same institution to predict the incidence of OASIs.

Results

Data on 16,920 births were analysed. OASIs occurred in 616 (3.6%) of all vaginal deliveries between 2004 and 2008. Significant (p < 0.05) variables that increased the risk of OASIs on multivariate analysis were: African-Caribbean descent, water immersion in labour, water birth, ventouse delivery, forceps delivery. The following variables remained independently significant in decreasing the risk of OASIs: South Asian descent, vaginal multiparity, current smoker, home delivery. The subsequent odds ratios were then used to construct a risk-scoring algorithm that was tested on a separate cohort of patients, showing a sensitivity of 52.7% and specificity of 71.1%.

Conclusions

We have confirmed known risk factors previously associated with OASIs, namely parity, birth weight and use of instrumentation during delivery. We have also identified several previously unknown factors, namely smoking status, ethnicity and water immersion. This paper identifies a risk scoring system that fulfils the criteria of a reasonable predictor of the risk of OASIs. This supersedes current practice where no screening is implemented other than examination at the time of delivery by a single examiner. Further prospective studies are required to assess the clinical impact of this scoring system on the identification and prevention of third degree tears.

【 授权许可】

   
2014 McPherson et al.; licensee BioMed Central Ltd.

【 图 表 】

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