(a) The number of females having their first baby who had an episiotomy during a non-instrumental vaginal birth, divided by the number of females having their first baby who had a non-instrumental vaginal birth, and multiplied by 100.

(b) The number of females having their first baby who had an episiotomy during an instrumental vaginal birth, divided by the number of females having their first baby who had an instrumental vaginal birth, and multiplied by 100.

A birth is defined as the complete expulsion or extraction from a female, of a product of conception of 20 or more completed weeks of gestation or of 400 grams or more birthweight.

Included are those females who gave birth for the first time and had a vaginal birth, with or without instruments. Females who had a multiple birth are included if this was the first time they had given birth.

Excluded are those females who did not give birth for the first time or gave birth by caesarean section.

Instrumental vaginal birth means that the baby was delivered with the use of forceps or vacuum extraction.

100 × (Numerator ÷ Denominator)

(a) The number of females having their first baby who had an episiotomy during a non-instrumental vaginal birth.

(b) The number of females having their first baby who had an episiotomy during an instrumental vaginal birth.

(a) The number of females having their first baby who had a non-instrumental vaginal birth

(b) The number of females having their first baby who had an instrumental vaginal birth.

• Year of birth
• State or territory of birth
• Mother's age at birth
• Hospital annual number of births
• Hospital sector
• Primary Health Network (from mother's area of usual residence)
• Statistical local area 3 (from mother's area of usual residence)

Data elements are from the Perinatal National Minimum Data Set (NMDS) or have been provided as voluntary non-standardised items by the states and territories. Records with a permissible value have been included in the denominator.

In 2004-2013 analysis, total number of episiotomy was been calculated using the perineal status item in the Perinatal NMDS 2013-14, by combining code 5 (episiotomy) and 6 (combined laceration and episiotomy). However, there is no information on the degree of laceration on code 6. Therefore, there is an undercount in the degree of laceration.

In 2014, there was a revision of the perineal status data items in the Perineal NMDS 2014-2018 from 2014. This meant that the perineal status was split between seven perineal status data items, which captures the perineal status relevant to each delivery. As a result, the episiotomy can be calculated using one data item, Perineal status: Episiotomy (code 5). Note that a female can have both an episiotomy and recorded laceration, the new data item has been adjusted to allow this.

Source of definition: Core Maternity Indicator Project, Indicator 4 (WHA 2007).

N[NN.N]

WHA (Women's Healthcare Australasia) 2007. Supporting excellence in maternity care: the core maternity indicators project: findings from the core maternity indicators project. Canberra: WHA.