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Sex Ratios at Birth Following Non-Invasive Prenatal Testing in Victoria, Australia
Hilary Bowman-Smart1,2, Christopher Gyngell2, Lisa Hui3,4
1Australian Centre for Precision Health, College of Health, Adelaide University, Adelaide, Australia.
Prenatal Diagnosis
|January 28, 2026
Summary
Non-invasive prenatal testing (NIPT) did not show an overall skewed sex ratio at birth in Australia. Further research is needed to explore potential sex selection practices with NIPT use.
Area of Science:
- Reproductive Health
- Genetics
- Public Health
Background:
- Non-invasive prenatal testing (NIPT) allows early determination of fetal sex.
- The potential for sex selection using NIPT is a growing concern.
- Limited evidence currently exists on the practice of sex selection via NIPT.
Purpose of the Study:
- To assess the sex ratio at birth (SRB) in infants born after NIPT.
- To investigate potential biases in SRB related to maternal demographics.
- To evaluate the impact of NIPT on sex selection practices in Australia.
Main Methods:
- Linking NIPT records with Victorian birth records (2014-2018).
- Calculating SRB and relative risk of male births based on maternal region, parity, and age.
- Defining the natural SRB range as 1.04-1.06.
Main Results:
- Analysis included 43,665 NIPT records, with 88.5% linked to birth records.
- The overall SRB was 1.05, falling within the natural range.
- Mothers from Southern and Central Asia showed a slightly increased relative risk of male births.
Conclusions:
- No overall skewed SRB was observed in Australian NIPT users.
- Findings suggest the need for larger studies on NIPT and sex selection.
- Further research is warranted to understand NIPT's role in reproductive choices.
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