Secular Trends in Preterm Birth Rates: Uncovering the Primary Challenge for Perinatal Medicine in Greece

Area of Science:

• Perinatal epidemiology
• Public health
• Reproductive health

Background:

• Preterm birth is a major cause of infant mortality with long-term consequences for mothers and infants.
• Understanding national trends in preterm birth rates is crucial for public health interventions.

Purpose of the Study:

• To analyze the time trends of national preterm birth rates (PBRs) in Greece from 1980 to 2022.
• To identify changes in PBRs across different gestational age groups.

Main Methods:

• Utilized official national live birth data from the Hellenic Statistical Authority (1980-2022).
• Calculated annual total PBRs and rates for gestational age groups per 100 live births.
• Employed joinpoint regression analysis to assess time trends, calculating Annual Percent Changes (APC) and Average Annual Percent Changes (AAPC) with 95% confidence intervals.

Main Results:

• The PBR declined from 4.66% in 1980 to 2.77% in 1991, then increased dramatically to 12.07% by 2018 and 11.90% in 2022.
• From 1991 to 2022, moderate (32-33 weeks) and late (34-36 weeks) preterm births showed the sharpest increases (AAPC 4.9% and 5.8%, respectively).
• Extremely (<28 weeks) and very (28-31 weeks) preterm births grew at slower rates (AAPC 2.2% and 0.7%, respectively).

Conclusions:

• The Greek PBR more than quadrupled between 1991 and 2022, largely due to increases in moderate and late preterm births.
• While the rate of increase has slowed since 2011, the PBR remains significantly higher than in other developed nations.
• The high PBR presents challenges for prevention strategies and perinatal care in Greece.