A Decade of Non-Invasive Prenatal Testing (NIPT) for Chromosomal Abnormalities in Croatia: First National Monocentric Study to Inform Country's Future Prenatal Care Strategy.

BACKGROUND

Chromosomal numerical and structural alterations are significant causes of various developmental disorders in foetuses. Non-invasive prenatal testing (NIPT) has emerged as an effective screening tool for detecting common aneuploidies, aiding in the identification of individuals who may require further diagnostic work-up.

METHODS

This retrospective, monocentric observational study evaluates the usage patterns, test choices, turnaround times (TAT), and outcomes of NIPT between 2013 and 2023 on a sample of 2431 pregnant women at a special hospital offering outpatient services and comprehensive gynaecological/obstetric inpatient care. We analysed the trends in NIPT usage, high-risk results, prior screening procedures, as well as factors such as age, gestational age and in vitro fertilisation (IVF) status. NIPT was performed using cell-free foetal DNA (cffDNA) extracted from maternal plasma, followed by library construction, sequencing and result analysis. The sequencing results were aligned with reference genomes, and z-scores were calculated to assess the likelihood of aneuploidy. Statistical significance was set at < 0.05.

RESULTS

The average age of women undergoing NIPT decreased from 36.1 years in 2013 to 33.01 years in 2023 ( = 0.0287), and mean TAT dropped from 12.44 days in 2013 to 7.08 days in 2023 ( = 0.0121), with the most substantial reduction occurring between 2013 and 2019. The study identified a stable rate of women who underwent IVF seeking prenatal testing, with no statistically significant difference between the first half and the second half of the analysed period ( = 0.2659). Among high-risk results, there were 39 chromosomal abnormalities detected, most of them belonging to trisomy 21 (59%).

CONCLUSIONS

Our findings demonstrate the increasing efficiency and accessibility of NIPT in prenatal care in Croatia, while the significant reduction in TAT and the decreasing age of women undergoing NIPT reflect enhanced operational practices and broader acceptance. Introducing NIPT into the public healthcare system in the Republic of Croatia could improve equitable access to advanced prenatal care and enhance pregnancy outcomes. Future advancements in technology and genetic counselling will further enhance its role, requiring careful attention to ethical and regulatory considerations.