Elsevier

Midwifery

Volume 23, Issue 2, June 2007, Pages 196-203
Midwifery

An Australian prospective cohort study of risk factors for severe perineal trauma during childbirth

https://doi.org/10.1016/j.midw.2006.04.004Get rights and content

Abstract

Objective

to determine risk factors for the occurrence of severe perineal trauma (third and fourth degree tears) during childbirth.

Design

a prospective cohort study was conducted using the hospital's computerised obstetric information system. Additional data were gathered on women who sustained severe perineal trauma. Descriptive statistics and logistic regression were used to assess risk factors for severe perineal trauma. Midwives were asked to comment on possible reasons for severe perineal trauma. Written responses made by midwives were analysed using content analysis. Discussion groups with midwives were held to further explore their experiences.

Setting

Royal Prince Alfred Hospital, Sydney, Australia.

Participants

all women having vaginal births (n=6595) in a 2-year period between 1 April 1998 and 31 March 2000, in both the birth centre and the labour ward.

Measurements and findings

2% of women (n=134) experienced severe perineal trauma. One hundred and twenty-two women had third-degree tears and 12 had fourth-degree tears. Primiparity, instrumental delivery, Asian ethnicity and heavier babies were associated with an elevated risk of severe perineal trauma. Midwives identified several factors they believed contributed to severe perineal trauma. These were lack of effective communication with the woman during the birth, different birth positions, delivery technique, ethnicity and obstetric influences.

Key conclusions

findings support current knowledge that primiparity, instrumental birth, heavier babies and being of Asian ethnicity are associated with increased rates of severe trauma. Specific attention needs to be paid to the strong association found between being of Asian ethnicity and experiencing severe perineal trauma.

Implications for practice

further identification and validation of the concerns expressed by midwives to reduce severe perineal trauma is warranted so that preventative strategies can be used and researched.

Introduction

Perineal trauma after childbirth can cause short- and long-term complications for women. Severe perineal trauma can cause long-term complications, such as involuntary loss of faeces and flatus. After third-degree perineal tears, up to 85% of women have persistent sphincter defects and up to 50% have anorectal complaints (Sultan et al., 1993b; Haadem and Gudmundsson, 1997; Poen et al., 1998). There is increasing evidence that instrumental delivery is a risk factor for severe perineal trauma (Sultan et al., 1993a, Sultan et al., 1993b; MacArthur et al., 1997; Donnelly et al., 1998). Randomised trials have shown that episiotomy is not effective in reducing the rate of severe perineal trauma and may indeed be harmful (Harrison and Brennan, 1984; Sleep et al., 1984; House et al., 1986; Sleep and Grant, 1987; Klein et al., 1992; Argentine Episiotomy Trial Collaborative Group, 1993; Eltorkey et al., 1994). There is also evidence that the lithotomy position, fetal malpositions, fetal macrosomia, certain racial and ethnic groups (Rizk and Thomas, 2000; Goldberg et al., 2003), perineal body length (Deering, et al., 2004), women of low socio-economic status and very young teenagers are more likely to sustain perineal trauma (Renfrew et al., 1998).

In 1998, midwives and doctors at a tertiary maternity unit in Sydney, Australia, became concerned that their severe perineal trauma rate (1.9%) was one of the highest in the state of New South Wales (NSW) (NSW Health, 1998). This was despite a relatively low episiotomy rate of 11.8%, compared with 18.1% for NSW and an instrumental delivery rate of 11.8%, compared with 10.5% for the State. The high numbers of women from Asian backgrounds (19%) (NSW Health, 1998) giving birth in the maternity unit was hypothesised by many of the midwives and doctors to partly explain the high severe perineal trauma rate. This study was designed to identify the risk factors for severe perineal trauma in this population in order to help midwives and doctors reduce the rate, improve their practice and thereby contribute to the improved well-being of childbearing women. It was also hoped that a prospective study would ensure correct identification of all severe perineal trauma and an accurate incidence could be determined.

Section snippets

Design

A prospective cohort study was conducted over a 2-year period.

Setting

The hospital in which the study was undertaken is situated in central Sydney and cares for a significant proportion of women from non-English-speaking backgrounds (NESB). More than 45% of women are from NESBs, with 19% being born in an Asian country (NSW Health, 1998). ‘Asian’ was defined as being born in the following countries: China, Vietnam, Hong Kong, Indonesia, Japan, Laos, Cambodia, Taiwan, North Korea, South Korea, Thailand,

Findings

The overall incidence of severe perineal trauma in the sample was 2% (n=134). There were 122 third-degree tears (91%) and 12 (9%) fourth-degree tears. There was one repeat third-degree in the 2-year study period. Severe perineal trauma remained stable during the 2-year period.

No significant difference in mean maternal age was found between women who had severe perineal trauma and those who did not. Women who had severe trauma were less likely to have private health insurance, more likely to be

Discussion

This study has a number of limitations. The way women from individual Asian countries were categorised under one classification of ‘Asian’ makes individual analysis difficult. Individual ethnic variations are lost in such a classification system. As country of birth rather than ethnicity is recorded, some women who were classified as non-Asian could be second-generation Asian women born in Australia. Nonetheless, this system of classification was seen as a way to further explore this issue with

Conclusion

In this study, being primiparous, being of Asian ethnicity or having instrumental births put women at increased risk of sustaining severe perineal trauma during birth. In order to try and reduce the incidence of severe perineal trauma, effort needs to be made to reduce the incidence of instrumental deliveries. More research is needed into methods for reducing the incidence of severe trauma in women of Asian ethnicity; into reducing oedematous perineums during birth; the effect of fear and lack

Acknowledgment

The authors would like to thank the midwives involved in the study.

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