Implementing minimum threshold for reporting neonatal mortality rates may minimize international variations in these rates: JAMA

Comparing neonatal mortality rates (NMRs) globally is crucial but difficult due to differing standards for documenting live births and the practices of obstetricians regarding the registration of periviable newborns in various countries. Recent cross-sectional study examined international variations in neonatal mortality rates (NMRs) with and without a minimum threshold (MT) of 22 weeks' gestational age or 500g birth weight in 2010 and 2020. The researchers obtained NMR data from the OECD Health Statistics and calculated 95% confidence intervals for the NMRs, differences, and ratios between NMRs with and without an MT for each country. In 2010, the analysis included 12,988,445 live births and 37,620 neonatal deaths across 30 countries. Six countries (Austria, New Zealand, Germany, Taiwan, UK, and US) showed significant differences in NMRs with and without an MT, while 12 countries revealed the same NMRs. In 2020, with 8,039,571 live births and 21,820 neonatal deaths across 26 countries, 4 countries (Austria, Taiwan, Switzerland, US) had significant differences, and 8 countries showed the same NMRs. The countries with significant differences exhibited improvements in their rankings when considering the MT. For example, in 2020 Switzerland, Austria, and Taiwan moved up in the NMR rankings when the MT was applied. The researchers note that countries with significant differences may have a higher proportion of obstetricians using a definition-based approach, leading to more periviable newborns, including elective terminations, being registered as live births. Conversely, the countries showing the same NMRs with and without an MT likely had various registration criteria for live births in their official published neonatal and infant mortality rates, as indicated by an OECD report.

Limitations

One limitation is that the exact number of neonatal deaths with an MT in each country was unavailable, and the estimated values would be lower than the actual numbers.

Conclusion

In conclusion, the introduction of an MT to improve the comparability of NMRs across countries has led to decreased international variations in NMRs. However, some countries exhibited greater improvements than others, potentially due to differences in obstetrician practices regarding the registration of periviable newborns as live births.

Key Points

1. The study examined international variations in neonatal mortality rates (NMRs) with and without a minimum threshold (MT) of 22 weeks' gestational age or 500g birth weight in 2010 and 2020.

2. In 2010, 6 countries (Austria, New Zealand, Germany, Taiwan, UK, and US) showed significant differences in NMRs with and without an MT, while 12 countries revealed the same NMRs. In 2020, 4 countries (Austria, Taiwan, Switzerland, US) had significant differences, and 8 countries showed the same NMRs.

3. The countries with significant differences exhibited improvements in their NMR rankings when considering the MT. For example, in 2020 Switzerland, Austria, and Taiwan moved up in the NMR rankings when the MT was applied.

4. The researchers note that countries with significant differences may have a higher proportion of obstetricians using a definition-based approach, leading to more periviable newborns, including elective terminations, being registered as live births.

5. The countries showing the same NMRs with and without an MT likely had various registration criteria for live births in their official published neonatal and infant mortality rates.

6. The introduction of an MT has led to decreased international variations in NMRs, but some countries exhibited greater improvements than others, potentially due to differences in obstetrician practices regarding the registration of periviable newborns as live births.

Reference –

Fu-Wen Liang et al. (2024). Neonatal Mortality Rates With And Without A Minimum Threshold. *JAMA Network Open*, 7. https://doi.org/10.1001/jamanetworkopen.2024.47487

Introduction of minimum threshold to improve the comparability of neonatal mortality rates across countries has led to decreased international variations in neonatal mortality rates