Macarthur AJ, Macarthur C. Incidence, severity, and determinants of perineal pain after vaginal delivery: a prospective cohort study. Am J Obstet Gynecol. 2004;191(4):1199–204.
Schytt E, Lindmark G, Waldenstrom U. Physical symptoms after childbirth: prevalence and associations with self-rated health. BJOG. 2005;112(2):210–7.
Rathfisch G, Dikencik BK, Kizilkaya Beji N, Comert N, Tekirdag AI, Kadioglu A. Effects of perineal trauma on postpartum sexual function. J Adv Nurs. 2010;66(12):2640–9.
Sultan AH, Kamm MA, Hudson CN, Bartram CI. Third degree obstetric anal sphincter tears: risk factors and outcome of primary repair. BMJ (Clinical research ed). 1994;308(6933):887–91.
Way S. A qualitative study exploring women's personal experiences of their perineum after childbirth: expectations, reality and returning to normality. Midwifery. 2012;28(5):e712–9.
Reid AJ, Beggs AD, Sultan AH, Roos AM, Thakar R. Outcome of repair of obstetric anal sphincter injuries after three years. Int J Gynaecol Obstet. 2014;127(1):47–50.
Albers LL, Sedler KD, Bedrick EJ, Teaf D, Peralta P. Midwifery care measures in the second stage of labor and reduction of genital tract trauma at birth: a randomized trial. J Midwifery Womens Health. 2005;50(5):365–72.
McCandlish R, Bowler U, van Asten H, Berridge G, Winter C, Sames L, Garcia J, Renfrew M, Elbourne D. A randomised controlled trial of care of the perineum during second stage of normal labour. Br J Obstet Gynaecol. 1998;105(12):1262–72.
Laine K, Rotvold W, Staff AC. Are obstetric anal sphincter ruptures preventable?-- large and consistent rupture rate variations between the Nordic countries and between delivery units in Norway. Acta Obstet Gynecol Scand. 2013;92(1):94–100.
National Board of health and Welfare. Graviditeter, förlossningar och nyfödda barn. Medicinska födelseregistret 1973–2014. (National data from the Swedish Birthregister - annual report 1973–2014), vol. 2016. Welfare NBoha; 2015. http://www.socialstyrelsen.se/publikationer2015/2015-12-27
Bjarnadottir RG, Smárason AK, Pálsson GI. Faedingarskráningunni fyrir árid 2013. (Report from the Icelandic Birth Registry for 2013), vol. 2016. National Hospital of Iceland R; 2013. http://www.landspitali.is/library/Sameiginlegar-skrar/Gagnasafn/Rit-og-skyrslur/Faedingaskraningar/faedingarskraning_skyrsla_2013.pdf.
de Leeuw JW, Struijk PC, Vierhout ME, Wallenburg HC. Risk factors for third degree perineal ruptures during delivery. BJOG. 2001;108(4):383–7.
Elfaghi I, Johansson-Ernste B, Rydhstroem H. Rupture of the sphincter ani: the recurrence rate in second delivery. BJOG. 2004;111(12):1361–4.
Raisanen SH, Vehvilainen-Julkunen K, Gissler M, Heinonen S. Lateral episiotomy protects primiparous but not multiparous women from obstetric anal sphincter rupture. Acta Obstet Gynecol Scand. 2009;88(12):1365–72.
Valsky DV, Lipschuetz M, Bord A, Eldar I, Messing B, Hochner-Celnikier D, Lavy Y, Cohen SM, Yagel S. Fetal head circumference and length of second stage of labor are risk factors for levator ani muscle injury, diagnosed by 3-dimensional transperineal ultrasound in primiparous women. Am J Obstet Gynecol. 2009;201(1):91.e91–97.
Samuelsson E, Ladfors L, Wennerholm UB, Gareberg B, Nyberg K, Hagberg H. Anal sphincter tears: prospective study of obstetric risk factors. BJOG. 2000;107(7):926–31.
Carroli G, Mignini L. Episiotomy for vaginal birth. The Cochrane database of systematic reviews. 2009;(1):Cd000081.
Gottvall K, Allebeck P, Ekeus C. Risk factors for anal sphincter tears: the importance of maternal position at birth. BJOG. 2007;114(10):1266–72.
Rygh AB, Skjeldestad FE, Korner H, Eggebo TM. Assessing the association of oxytocin augmentation with obstetric anal sphincter injury in nulliparous women: a population-based, case–control study. BMJ open. 2014;4(7), e004592.
Samuelsson E, Ladfors L, Lindblom BG, Hagberg H. A prospective observational study on tears during vaginal delivery: occurrences and risk factors. Acta Obstet Gynecol Scand. 2002;81(1):44–9.
Lindgren HE, Radestad IJ, Christensson K, Hildingsson IM. Outcome of planned home births compared to hospital births in Sweden between 1992 and 2004. A population-based register study. Acta Obstet Gynecol Scand. 2008;87(7):751–9.
Hutton EK, Reitsma AH, Kaufman K. Outcomes associated with planned home and planned hospital births in low-risk women attended by midwives in Ontario, Canada, 2003–2006: a retrospective cohort study. Birth (Berkeley, Calif). 2009;36(3):180–9.
McPherson KC, Beggs AD, Sultan AH, Thakar R. Can the risk of obstetric anal sphincter injuries (OASIs) be predicted using a risk-scoring system? BMC research notes. 2014;7:471.
Brocklehurst P, Hardy P, Hollowell J, Linsell L, Macfarlane A, McCourt C, Marlow N, Miller A, Newburn M, Petrou S, et al. Perinatal and maternal outcomes by planned place of birth for healthy women with low risk pregnancies: the Birthplace in England national prospective cohort study. BMJ (Clinical research ed). 2011;343:d7400.
Hildingsson IM, Lindgren HE, Haglund B, Radestad IJ. Characteristics of women giving birth at home in Sweden: a national register study. Am J Obstet Gynecol. 2006;195(5):1366–72.
Lindgren H, Kjaergaard H, Olafsdottir OA, Blix E. Praxis and guidelines for planned homebirths in the Nordic countries - an overview. Sex Reprod Healthc. 2014;5(1):3–8.
Lindgren HE, Brink A, Klinberg-Allvin M. Fear causes tears - perineal injuries in home birth settings. A Swedish interview study. BMC Pregnancy Childbirth. 2011;11:6.
Dahlen HG, Dowling H, Tracy M, Schmied V, Tracy S. Maternal and perinatal outcomes amongst low risk women giving birth in water compared to six birth positions on land. A descriptive cross sectional study in a birth centre over 12 years. Midwifery. 2013;29(7):759–64.
Cortes E, Basra R, Kelleher CJ. Waterbirth and pelvic floor injury: A retrospective study and postal survey using ICIQ modular long form questionnaires. Eur J Obstet Gynecol Reprod Biol. 2011;155(1):27–30.
Smith LA, Price N, Simonite V, Burns EE. Incidence of and risk factors for perineal trauma: a prospective observational study. BMC Pregnancy Childbirth. 2013;13:59.
Shorten A, Donsante J, Shorten B. Birth position, accoucheur, and perineal outcomes: informing women about choices for vaginal birth. Birth (Berkeley, Calif). 2002;29(1):18–27.
Soong B, Barnes M. Maternal position at midwife-attended birth and perineal trauma: is there an association? Birth (Berkeley, Calif). 2005;32(3):164–9.
Aikins Murphy P, Feinland JB. Perineal outcomes in a home birth setting. Birth (Berkeley, Calif). 1998;25(4):226–34.
Gupta JK, Hofmeyr GJ, Shehmar M. Position in the second stage of labour for women without epidural anaesthesia. The Cochrane Database of Systematic Reviews. 2012;5:Cd002006.
Naroll F, Naroll R, Howard FH. Position of women in childbirth. A study in data quality control. Am J Obstet Gynecol. 1961;82:943–54.
Kemp E, Kingswood CJ, Kibuka M, Thornton JG. Position in the second stage of labour for women with epidural anaesthesia. The Cochrane Database of Systematic Reviews. 2013;1:Cd008070.
Blix E, Kumle MH, Ingversen K, Huitfeldt AS, Hegaard HK, Olafsdottir OA, Oian P, Lindgren H. Transfers to hospital in planned home birth in four Nordic countries - a prospective cohort study. Acta Obstet Gynecol Scand. 2016;95(4):420–8.
Homer CS, Thornton C, Scarf VL, Ellwood DA, Oats JJ, Foureur MJ, Sibbritt D, McLachlan HL, Forster DA, Dahlen HG. Birthplace in New South Wales. Australia: an analysis of perinatal outcomes using routinely collected data. BMC Pregnancy Childbirth. 2014;14:206.
Thiagamoorthy G, Johnson A, Thakar R, Sultan AH. National survey of perineal trauma and its subsequent management in the United Kingdom. Int Urogynecol J. 2014.
Baghestan E, Irgens LM, Bordahl PE, Rasmussen S. Trends in risk factors for obstetric anal sphincter injuries in Norway. Obstet Gynecol. 2010;116(1):25–34.
Stedenfeldt M, Oian P, Gissler M, Blix E, Pirhonen J. Risk factors for obstetric anal sphincter injury after a successful multicentre interventional programme. BJOG. 2014;121(1):83–91.
Priddis H, Dahlen H, Schmied V. What are the facilitators, inhibitors, and implications of birth positioning? A review of the literature. Women Birth. 2012;25(3):100–6.
De Jonge A, Lagro-Janssen AL. Birthing positions. A qualitative study into the views of women about various birthing positions. J Psychosom Obstet Gynaecol. 2004;25(1):47–55.
Downe S. Physiology and care during the transition and second stage phases of labour. In: Fraser DM, Cooper MA, editors. Myles textbook for midwives. Edinburgh: Churchill Livingstone; 2003.
How to perform an episiotomy [https://www.rcm.org.uk/news-views-and-analysis/analysis/how-to-perform-an-episiotomy]
Andrews V, Sultan AH, Thakar R, Jones PW. Occult anal sphincter injuries--myth or reality? BJOG. 2006;113(2):195–200.
Andrews V, Thakar R, Sultan AH. Structured hands-on training in repair of obstetric anal sphincter injuries (OASIS): an audit of clinical practice. Int Urogynecol J Pelvic Floor Dysfunct. 2009;20(2):193–9.
Blix E, Kumle MK, Ingversen K, Huitfeldt AS, Hegaard HK, Ólafsdóttir OÁ, Oian P, Lindgren H. Transfers to hospital in planned home births in four Nordic countries. 2016.
Aasheim V, Nilsen AB, Lukasse M, Reinar LM. Perineal techniques during the second stage of labour for reducing perineal trauma. The Cochrane database of systematic reviews. 2011(12):Cd006672.