The number of WA women having babies over the age of 35 continues to rise but the state’s overall birthrate is falling.

In WA, the fertility rate was 1.87 babies per woman, with a median age of 31 years according to new data from the Australian Bureau of Statistics.

Back in 2011, the state’s fertility rate was 1.93 babies per woman but the median age sat at 30.3 years.

For women aged 35-39, fertility rates jumping from 64.9 to 70.9 between 2011 and 2017.

But the fertility for women in the 25-29, 20-24 and 15-19 age brackets all fell sharply.

Nationwide, the fertility rate of Australian women aged 35 years and over continues to rise, but the rate in most other age groups is falling.

A total of 309,142 births were registered in Australia in 2017, resulting in a total fertility rate of 1.74 babies per woman, the lowest since 2001.

ABS Director of Demography, Anthony Grubb, said: "The long-term decline in fertility of younger mums as well as the continued increase in fertility of older mums reflects a shift towards late childbearing. Together, this has resulted in a rise in median age of mothers and a fall in Australia's total fertility rate.”

SNAPSHPOT OF BIRTHS IN 2017

Total births WA: 33,991
Multiple WA births (twin, triplets etc): 515
Boys born in Australia: 159,221
Girls born in Australia: 149,921
65.2 per cent of births were to parents in a registered marriage