Trisomy 21 - incidence, diagnostics and pregnancy terminations 1999-2018.

Area of Science:

• Prenatal diagnostics
• Genetics
• Public Health

Background:

• Hypothesized differences in examinations offered at fetal medicine centers versus general maternity care in Norway.
• Investigated incidence, prenatal diagnostics, and pregnancy terminations for trisomy 21.
• Compared data from a national center with national Norwegian figures.

Purpose of the Study:

• To investigate the incidence, prenatal diagnostics, and pregnancy termination rates for trisomy 21.
• To compare these figures between a specialized fetal medicine center and national data in Norway.
• To explore potential reasons for observed differences in termination rates.

Main Methods:

• Retrospective analysis of data from 1999-2018.
• Comparison of national data (Medical Birth Registry of Norway) with local data (National Center for Fetal Medicine quality registry).
• Statistical analysis to assess trends and differences.

Main Results:

• National trisomy 21 incidence was 0.20%, increasing significantly over time, associated with maternal age.
• Local trisomy 21 incidence was 0.19%.
• In the local population, 68.2% received prenatal diagnosis, and 87.7% of those terminated; this termination rate was significantly higher than the national average.

Conclusions:

• While trisomy 21 incidence and prenatal diagnosis rates are comparable, specialized centers show significantly higher termination rates.
• Disparities in access to prenatal diagnostics may explain the higher termination rates observed at fetal medicine centers.
• Further investigation into diagnostic access and counseling practices is warranted.