Among those who gave birth in 2022, three in 10 previously experienced at least one miscarriage, and one in 10 had two or more, an Australian Institute of Health and Welfare (AIHW) report found.
Miscarriage was the most common type of pregnancy loss recorded in hospital data, accounting for around four in five hospitalisations, followed by ectopic pregnancy.
Women aged 30 to 39 accounted for about six in 10 pregnancy loss-related hospitalisations.
However, the indicative scoping study, which used data from five states and territories, did not reflect all experiences of pregnancy loss and instead provided a "partial view", said the report released on Wednesday.
It found there were clear gaps, as the study only examined pregnancy loss among women giving birth, hospital admissions and procedures for pregnancy loss.
Additionally, there is currently no routine or consistent national or jurisdictional reporting on pregnancy loss before 20 weeks' gestation, which impacts how care is planned, funded and delivered.
Gemma Killen, who used IVF to have a baby with her non-binary partner, experienced six pregnancy losses.
She said better data was needed to improve understanding of pregnancy loss prevalence in Australia's LGBTQI community, and provide better support.
"There's some research overseas that suggests that LGBT women have higher rates of miscarriage and pregnancy loss than heterosexual women," she told AAP.
"But we don't have that data in Australia, so we can't properly design programs or fund programs that respond to specific community need."
PANDA, which delivers the Pink Elephants Pregnancy Loss Helpline, said figures on pregnancy loss among those who had not given birth was necessary to build more caring responses.
"We know that the data doesn't represent those who may have ongoing fertility issues and may never have had the opportunity to have a bub," PANDA chief executive Julie Borninkhof told AAP.
"We have to acknowledge the loss associated there.
"The system needs to recognise that no one individual is the same, and we need to provide continuity of care, integrated care, and person-centred support to individuals, regardless of where they are on their journey of loss."
Ms Borninkhof, and the AIHW, also noted the data also did not recognise those who do not access health services or who only receive care through their GP.
"The study recommends practical steps towards more comprehensive and consistent monitoring, including in primary care," AIHW spokesperson Deanna Eldridge said.
"Better data will support policy and service delivery that reflect the experiences, care needs and outcomes of those affected by pregnancy loss in Australia."
The Early Pregnancy Loss Coalition, representing peak bodies in Australia's miscarriage space, said the study provided a clearer picture, and hoped it would inform public health policy.
"These numbers now confirm what the EPLC and its members always contended: miscarriage rates are far higher than previously estimated and represent significant hospital admission numbers," executive director Isabelle Oderberg said.
The research, commissioned by the federal government, is the first to analyse the National Perinatal Data Collection, National Hospital Morbidity Database, and the Medicare Benefits Schedule.
The AIHW made four recommendations, including creating a national pregnancy loss register to allow self-reporting, a sexual and reproductive health survey and a health care provider workforce survey.
Pink Elephants Pregnancy Loss Helpline 1300 726 306
Red Nose Grief and Loss Support 1300 308 307
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