Australia's mothers and babies 2004

Australia’s mothers and babies 2004 is the fourteenth report providing information on births in Australia from perinatal data collections for each state and territory. The report presents demographic, pregnancy and childbirth factors of women who gave birth in 2004 and the characteristics and outcomes of their babies. This edition includes a chapter on first-time mothers and their babies.

The report is produced by the AIHW National Perinatal Statistics Unit based at the University of New South Wales and can be used by researchers, academics, students, policy makers and health service planners, and those providing services in reproductive health.

Highlights

Mothers in 2004

• There were 257,205 babies born to 252,871 mothers in 2004 reported to the National Perinatal Data Collection.
• The median age of women who gave birth was 30.0 years, continuing the upward trend seen in maternal age in recent years. There were 49,411 mothers aged 35 years or older (19.5%).
• Women who reported smoking at all during pregnancy accounted for 16.7% of women who gave birth in the five jurisdictions for which data were available. This represents a decrease since 2001.
• Of women who gave birth, 59.2% had a spontaneous vaginal birth and 0.4% had a vaginal breech birth. Deliveries using forceps accounted for 3.9% and vacuum extractions for 7.1%.
• The increase in caesarean sections continued with 29.4% of mothers having caesarean section deliveries in 2004, compared with 19.3% in 1995. Over the same period, instrumental deliveries have remained stable at around 11%. Caesarean section rates were higher among older mothers and those who gave birth in private hospitals.
• Of multiparous mothers who gave birth, 24.5% had previously had a caesarean section. The proportion of these mothers who had a caesarean section in 2004 was 81.6%.
• Of mothers having an operative delivery, one-third had an epidural or caudal anaesthetic administered, and approximately half had a spinal anaesthetic. A general anaesthetic was administered for 5.5% of operative deliveries.
• There were 8,904 Aboriginal or Torres Strait Islander women who gave birth, making up 3.6% of all mothers in Australia in 2004.
• The average age of Aboriginal or Torres Strait Islander mothers who gave birth was 24.8 years, compared with 29.9 years for non-Indigenous mothers.
• Multiple pregnancies accounted for 1.7% of all pregnancies and included 4,175 twin pregnancies, 75 triplet pregnancies and three quadruplet and quintuplet pregnancies. The twinning rate was 16.5 per 1,000 mothers.
• There were 589 planned homebirths reported, representing 0.2% of women who gave birth in 2004. Of women who gave birth at home, 72.7% were multiparous.
• The estimated number of induced abortions in 2004 was 83,210.

Babies in 2004

• Of the 257,205 births in Australia, 20,999 (8.2%) were preterm (less than 37 weeks gestation). The average gestational age of all babies was 38.8 weeks in 2004.
• Low birthweight (less than 2,500 grams) occurred in 16,336 (6.4%) liveborn babies. The proportion of liveborn babies of Aboriginal or Torres Strait Islander mothers that were low birthweight was 13.2% compared with 6.1% of babies of non-Indigenous mothers.
• Of babies with breech presentations at birth, 87.6% were delivered by caesarean section.
• Male births exceeded female births, accounting for 51.4% of all births. The national sex ratio was 106.0 male live births per 100 female live births.
• Of liveborn babies, 15.6% were admitted to a special care nursery or neonatal intensive care unit.
• In 2004, 5,724 babies were admitted to level III neonatal intensive care units in Australia. This was a rate of 22.4 per 1,000 live births. Of these babies, 46.3% had a gestational age of less than 32 weeks and 39.3% had a birthweight of less than 1,500 grams.
• Using state and territory perinatal data, the fetal death rate was 7.5 per 1,000 births; the neonatal death rate was 3.1 per 1,000 live births; and the perinatal death rate was 10.5 per 1,000 births.
• The main categories of perinatal death, as classified by the Perinatal Society of Australia and New Zealand Perinatal Death Classification, were congenital abnormalities, spontaneous preterm births and unexplained antepartum deaths. These three groups of causes accounted for over half of perinatal deaths.

First-time mothers

• Women who gave birth for the first time in 2004 accounted for 42.2% of all women who gave birth. The average age of first-time mothers was 28.0 years, an increase from 26.5 years in 1995.
• Compared with multiparous mothers, first-time mothers had higher rates of induction, epidural anaesthesia and caesarean section, and lower rates of smoking during pregnancy.
• Around 9.2% of babies born to first-time mothers were preterm in 2004, compared with 7.4% of babies born to multiparous women.
• Low birthweight occurred in 7.6% of liveborn babies of primiparous women compared with 5.5% for multiparous women.