We read with interest the report by Zeitlin et al. of the Euro-Peristat preterm study group on time trends in preterm births in Europe 1996–2008. However, we noted that relevant data from Greece were not included. To improve the completeness of this report, we analysed official nationwide data on all live births for the reference period, starting at 22 weeks of gestation, in Greece, provided by the Hellenic Statistical Authority, EL.STAT and, following the same methodology, compared the Greek preterm birth rates (PBRs) with those of the 19 countries. Unfortunately, routine data on mode of onset of labour (induction or spontaneous) are unavailable.
Preterm birth rate (before 37 weeks of gestation) increased 2.6-fold exponentially (R2 = 0.956, P < 0.0001), from 3.68 in 1996 to 9.63 in 2008, with an average annual percentage change (AAPC) of +8.3%, which is substantially higher than in all 19 countries included in the study. In comparison with the 19 European countries, PBR in Greece was the lowest in 1996, second lowest in 2000 (5.44) and tenth in 2004 (6.97), whereas by 2008 it had risen to second highest place (9.63). Greece also had the highest 2000–2008 annual trends with the same AAPC value of +7.0% for both singleton and multiple live births. Moreover, the rate accelerated during the most recent years, 2002–2010 (AAPC + 9.4%), and PBR reached 11.18 in 2010, decreasing slightly in 2011 (10.97).
In 1996, 2000, 2004 and 2008, PBRs in singleton births were 3.10, 4.16, 5.24 and 7.16%, respectively, and PBRs in multiple births were 21.27, 35.17, 43.46 and 60.25%, respectively. For both singleton and multiple births, Greece had the lowest PBR values in 1996 and 2000, whereas in 2008 it occupied third and fifth positions, respectively. During the period 1996–2008, PBR rose +2.3-fold in singleton births, with an AAPC of +7.2%, and +2.8-fold in multiple births, with an AAPC of +9.1%. Both AAPC values are higher than in all 19 countries.
Increases in PBR were more marked for births at 35–36 weeks of gestation for both singleton (AAPC + 10.1%) and multiple (AAPC + 12.2%) births, in comparison with births at 32–34 weeks of gestation (singleton births AAPC +3.7%, multiple births AAPC + 7.9%). For preterm births at < 32 weeks of gestation the changes were less pronounced, with an AAPC + 1.7% for singleton births (the overall 1996–2008 trend being nonsignificant, P = 0.878) and an AAPC + 2.9% for multiple births.
Multiple births as a proportion of all live births (multiple birth rate, MBR) increased from 3.16 to 4.66 per 100 live births, with an AAPC of + 3.3%, which is the third highest among the countries studied. The MBR in Greece in 2008 was higher than in all 19 countries and rose further to 5.26 in 2010. There was an almost perfect positive correlation between the increase in PBR and MBR (Spearman's ρ = 0.956, P < 0.0001), substantially higher than that found for the other European countries (ρ = 0.66). The population attributable risk (PAR%) of multiple births in 2008 was 25.7%, putting Greece in third place.
In recent years, Greece has had the most rapidly worsening rates of PTBs among the 19 European and 39 most developed countries, a phenomenon which has become the severest public health concern in Greek obstetrics.[3, 4]
Disclosure of interest
The authors report no conflict of interest.