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. 2014 Jul 24;4(7):e004592.
doi: 10.1136/bmjopen-2013-004592.

Assessing the association of oxytocin augmentation with obstetric anal sphincter injury in nulliparous women: a population-based, case-control study

Astrid B Rygh  1 , Finn Egil Skjeldestad  2 , Hartwig Körner  3 , Torbjørn M Eggebø  4
Affiliations

Assessing the association of oxytocin augmentation with obstetric anal sphincter injury in nulliparous women: a population-based, case-control study

Astrid B Rygh et al. BMJ Open. .

Abstract

Objective: To assess the association of oxytocin augmentation with obstetric anal sphincter injury among nulliparous women.

Design: Population-based, case-control study.

Setting: Primary and secondary teaching hospital serving a Norwegian region.

Population: 15 476 nulliparous women with spontaneous start of labour, single cephalic presentation and gestation ≥37 weeks delivering vaginally between 1999 and 2012.

Methods: Based on the presence or absence of oxytocin augmentation, episiotomy, operative vaginal delivery and birth weight (<4000 vs ≥4000 g), we modelled in logistic regression the best fit for prediction of anal sphincter injury. Within the modified model of main exposures, we tested for possible confounding, and interactions between maternal age, ethnicity, occiput posterior position and epidural analgaesia.

Main outcome measure: Obstetric anal sphincter injury.

Results: Oxytocin augmentation was associated with a higher OR of obstetric anal sphincter injuries in women giving spontaneous birth to infants weighing <4000 g (OR 1.8; 95% CI 1.5 to 2.2). Episiotomy was not associated with sphincter injuries in spontaneous births, but with a lower OR in operative vaginal deliveries. Spontaneous delivery of infants weighing ≥4000 g was associated with a threefold higher OR, and epidural analgaesia was associated with a 30% lower OR in comparison to no epidural analgaesia.

Conclusions: Oxytocin augmentation was associated with a higher OR of obstetric anal sphincter injuries during spontaneous deliveries of normal-size infants. We observed a considerable effect modification between the most important factors predicting anal sphincter injuries in the active second stage of labour.

Keywords: Epidemiology.

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References

    1. Baghestan E, Irgens LM, Bordahl PE, et al. Trends in risk factors for obstetric anal sphincter injuries in Norway. Obstet Gynecol 2010;116:25–34 - PubMed
    1. Laine K, Skjeldestad FE, Sanda B, et al. Prevalence and risk factors for anal incontinence after obstetric anal sphincter rupture. Acta Obstet Gynecol Scand 2011;90:319–24 - PubMed
    1. Dudding TC, Vaizey CJ, Kamm MA. Obstetric anal sphincter injury: incidence, risk factors, and management. Ann Surg 2008;247:224–37 - PubMed
    1. Sultan AH, Thakar R, Fenner DE. Perineal and anal sphincter trauma: diagnosis and clinical management. New York; London: Springer, 2009
    1. Jander C, Lyrenas S. Third and fourth degree perineal tears. Predictor factors in a referral hospital. Acta Obstet Gynecol Scand 2001;80:229–34 - PubMed

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