The Alveofact and Poractant groups spent fewer days on the ventilator, needed fewer days of oxygen administration and spent fewer days in hospital compared with the Beractant group but no differences were observed among the three groups with regards to mortality and morbidity.

The aim of the study was to estimate the risk of pre-term birth in women giving birth in Greece in different age groups. Data about women giving birth in Greece were retrieved from the Hellenic Vital Statistics covering the years from 1999 to 2008. Relative risk using χ(2) contingency tables was estimated among maternal age groups formed. These groups included mothers < 15 years of age, 15-19, 20-34 (used as a control group) and women > 34 (35-39, 40-44, 45-49 and ≥ 50) years of age. Relative risk of each age group was compared with mothers 20-34 years of age. A total of 1,069,413 valid births were included in the study and 72,156 of them were pre-term (6.75% of total count). Results exhibit a 'U'-shaped distribution of risk. Higher risk of pre-term birth is noted in the groups of < 15 years (Pearson χ(2) = 14.964, p < 0.001, risk = 1.569, CI = 1.249-1.970) and above 34 years of age (Pearson χ(2) = 2991.26, p < 0.001, risk = 1.572, CI = 1.546-1.597). For older women, a steep rise in the relative risk for pre-term birth was noted beyond the 40-44 years of age group. Finally, of interest is the fact that 'late' pre-terms (34-36 gestational weeks) account for most of the pre-term birth in mothers beyond 34 years of age.

Although preterm birth etiology is multifactorial, the selective rise in the "late preterm" group possibly was due to an increase in medical reasons necessitating a preterm delivery, changes in obstetric practice, or both. Further studies are needed to estimate the precise effect of each contributing factor.

Evidence for seasonality of preterm birth was shown and extreme weather was associated with a higher incidence of it.