The Great Divide: Country of birth as a risk factor for obstetric anal sphincter injuries

Abstract

BackgroundObstetric anal sphincter injuries (OASIS) can complicate up to 6% of births and are a major contributor to preventable maternal morbidity. Asian women have a risk of third and fourth degree perineal tears up to four times greater than women of other ethnicities in the same community, but the lack of differentiation of Asian women into regional groups has limited insight into the reasons behind their increased risk.AimsTo investigate risk of OASIS associated with country of birth.MethodsThis was a retrospective cohort study of all women with a singleton, nulliparous pregnancy who delivered vaginally by spontaneous vaginal birth or an instrumental delivery between 1 January 2009 and 31 December 2015. The demographics of women who experienced OASIS were compared with those women who had minor perineal trauma.ResultsFrom January 2009 to December 2015 there were 10 750 singleton, nulliparous and natural vaginal birth (NVB), forceps or vacuum deliveries. Of these deliveries, 581 (5.4%) werehad third degree tears and 36 (0.3%) fourth degree tears. Women born in South Asia were at a much higher risk of OASIS than other groups, including women born in other Asian countries, compared to the Australian/New Zealand cohort. One in every 10 nulliparous South Asian women having a singleton vaginal or instrumental delivery will sustain an OASIS.ConclusionsOur study further confirms the role of Asian ethnicity in the risk of OASIS, and is the second to confirm that South Asian women are at a dramatically increased risk.

‘Please Squeeze’: A novel approach to perineal guarding at the time of delivery reduced rates of obstetric anal sphincter injury in an Australian tertiary hospital

“…The risk factor of ethnicity was not investigated in this audit as the primary outcome was if perineal protection was effective at reducing the incidence of OASIS. The impact of ethnicity has been reported elsewhere, and showed that women of South Asian country of birth were at increased risk of OASIS 20 …”

“…This was a retrospective observational audit over two 36-month time periods, before and after implementation of the 'Please Squeeze' program at a tertiary level hospital. This unit delivers over 5500 babies per annum and cares for women from very diverse ethnic backgrounds, 20 making it an ideal study population.…”

“…The impact of ethnicity has been reported elsewhere, and showed that women of South Asian country of birth were at increased risk of OASIS. 20 The primary outcome of this audit was OASIS incidence for all vaginal deliveries. Secondary outcomes included the incidence of episiotomy, OASIS following spontaneous vaginal delivery (SVD) and OASIS following assisted vaginal delivery.…”

“…This was a retrospective observational audit over two 36‐month time periods, before and after implementation of the ‘Please Squeeze’ program at a tertiary level hospital. This unit delivers over 5500 babies per annum and cares for women from very diverse ethnic backgrounds, 20 making it an ideal study population. Data were analysed to determine baseline statistics prior to implementation as part of ongoing departmental audits, and then analysed following completion of the second 36‐month time period.…”

Obstetric anal sphincter injuries among women with gestational diabetes and women without gestational diabetes: A NSW population‐based cohort study

“…Several demographic factors have been identified as associated with OASIs. Asian ethnicity, maternal older age, first-time mother and giving birth in public hospitals are all associated with an increase in the risk of OASIs [6][7][8] . Instrumental vaginal birth, including forceps and vacuum births, has been identified as a major risk factor for OASIs 7,9 .…”