Changes in Neonatology: Comparison of Two Cohorts of Very Preterm Infants (Gestational Age <32 Weeks): The Project on Preterm and Small for Gestational Age Infants 1983 and The Leiden Follow-Up Project on Prematurity 1996-1997

Abstract
Objective. To determine changes in peri- and neonatal care concerning neonatal mortality and morbidity by comparing 2 cohorts of very prematurely born infants (gestational age [GA] Methods. The Leiden Follow-Up Project on Prematurity (LFUPP-1996/97), a regional, prospective study, includes all infants who were born alive after a GA n = 1338). For comparison, infants from the POPS-1983 cohort with a GA n = 102). Results. The absolute number of preterm births in the study region increased by 30%: 102 in 1983 to on average of 133 in 1996–1997. Centralization of perinatal care improved: the percentage of extrauterinely transported infants decreased from 61% in 1983 to 35% in 1996–1997. A total of 182 (73%) of the LFUPP-1996/97 infants were treated antenatally with glucocorticosteroids compared with 6 (6%) of the POPS-1983 infants. A total of 112 (42%) of the LFUPP-1996/97 infants received surfactant. In-hospital mortality decreased from 30% in the 1980s to 11% in the 1990s. Mortality of the extremely preterm infants (Conclusions. An increase in the absolute number of very preterm births in this study region was found, leading to a greater burden on the regional NICUs. Improvements in peri- and neonatal care have led to an increased survival of especially extremely preterm infants. However, increased survival has resulted in more morbidity, mainly bronchopulmonary dysplasia, at the moment of discharge from the hospital.