Parental ages in Australia
A mother in her 50s who conceived after IVF treatment has given birth to triplets in Adelaide, it was widely reported today. In response to requests for information about other births to older parents, the AIHW National Perinatal Statistics Unit at the University of New South Wales has analysed available data from the national register on assisted conception and from birth registrations to determine what proportion of all births to older parents occur after assisted conception (IVF and GIFT) and to provide some information on pregnancy outcome.
Commenting on these findings, the Unit's Director, Associate Professor Paul Lancaster, said 'while IVF and other types of assisted conception have increased the number of births at older parental ages, the majority of births to these older parents (more than 90%) are still conceived naturally.
'With increasing age, donor eggs or sperm are more likely to be used to achieve conception. Among women who become pregnant after assisted conception in their 40s or 50s, about 50-60% go on and have a liveborn infant. We still lack information on how many births to parents of all ages occur after fertility drugs or artificial insemination.'
The key findings are as follows:
- In recent years (1994-1996), an increasing proportion of all mothers giving birth in Australia are aged 40 or more. In 1996, there were 5,145 (2.1%) mothers in this age group. There were 155 (0.06%) mothers aged 45-49 years and 11 aged 50 or more.
- Paternal age is also increasing. In 1996, 1 in 10 fathers of all children born in Australia was aged 40 or more, 1 in 100 was 50 or more, and 1 in 1,000 was 60 or more.
- Infertile couples treated by assisted conception (IVF and GIFT) are well known to be older than couples who conceive naturally.
- In 1994-95, 1 in 25 (3.9%) of all births to mothers aged 40 or more followed assisted conception, increasing from 1 in 27 (3.7%) at 40-44 years to 1 in 12 (8.3%) at 45 or more.
- In 1994-95, the father was 40 or more for 36,777 births. Of these births, 1 in 37 (2.7%) resulted from assisted conception. The proportion of all births in Australia that occurred after assisted conception increased slightly with paternal age from 2.5% at 40-44 to 3.0% at 45-49 and 3.9% at 50-54, then declined again to 2.4% at 55-59 and 1.6% of those aged 60 or more.
- After assisted conception, 55.4% of 1,084 pregnancies to women aged 40-44 years resulted in live births. Among 54 women aged 45 and over, 44.6% of their pregnancies resulted in live births.
- Among more than 16,000 pregnancies resulting in births after assisted conception in Australia since 1979, 1,176 mothers were aged 40 or more (Table 1) and 3,256 fathers were aged 40 or more (Table 2).
- After assisted conception in Australia, the oldest mother giving birth was 56; the oldest mother of twins was 48; and the previous oldest mother of triplets was 43 years (Table 1). The oldest father of an infant born after assisted conception was in his 70s (Table 2).