Older mums-to-be are being reassured by Australian researchers that their age poses less of a risk to their health than pre-existing conditions like diabetes.
Having a chronic condition like diabetes or heart disease poses a greater health risk for older pregnant women than their age, Australian researchers have found.
A study of 99,000 mums aged over 35 found age was only a minimal risk factor in terms of the chance of them or their babies dying during childbirth or developing a severe health condition, especially for women who already had other children.
However older mums who had a pre-existing medical condition when they fell pregnant faced significantly higher risks of things going wrong for them and their babies.
Lead researcher Professor Jonathan Morris, of Sydney University's Kolling Institute, said the findings published in the Australian and New Zealand Journal of Obstetrics and Gynaecology are reassuring for older mums and their babies.
"We live in a society now where's there's a lot of societal discourse about advanced maternal age and the effects of age on pregnancy outcomes, although that is true for some conditions such as fertility and things like Downs syndrome," he told AAP.
"But what we think from the data is for those women who do have babies, the increased risk from advancing age is really quite low."
Given Australia has one of the world's highest rates of women older than 35 giving birth, the researchers wanted to find out if age posed a greater risk to the health of the mums and their babies than any pre-existing conditions including heart disease, obesity, and diabetes.
After examining birth and medical records for women aged 35-56 who had babies in NSW hospitals between 2006 and 2012, they found those who already had other children, pre-existing medical conditions and complications with previous pregnancies were at greatest risk of death and serious health problems.
However women who had given birth before but didn't have any pre-existing conditions or previous pregnancy complications were least likely to encounter problems.
"When we looked to see what the contribution of age was compared with other medical conditions it's quite clear that age is far less relevant than general health. That's the bottom line," Prof Morris said.
"Age has a far less significant effect than other health considerations, and particularly if a woman has had a straightforward pregnancy before, she can be reassured the risks aren't really appreciably higher."
A separate study in The Lancet published last September found mums aged over 35 accounted for 40 per cent of all maternal deaths in Australia.
Doctors have for years warned women that once they hit 35, they and their babies have a higher risk of developing health problems.