Preterm deliveries - Aetiological factors and consequences for the infants prognosis.

Purpose: io identify the most important pathologies leading to preterm labour. Is a decrease of preterm deliveries a logical expectation considering the main characteristics of these pathologies and the infants' prognosis? Patients and Method: A retrospective analysis and assignment to pathologies leading to preterm birth of 1018 preterm deliveries with 1172 newborn babies before 37 weeks of gestational age between 1988-07-01 and 1995-06-30 was performed. Results: As the most important pathologies we identified premature rupture of membranes (17.5%), multiple pregnancies (15.0%), fetal malformations (14.6%), preterm labour (13.3%), fetal haemolysis (10.5%), hypertensive disease in pregnancy (9.3%) and intrauterine growth retardation without recognisable aetiology (9.3%). Neonatal mortality was 50% (46/92) up to 28 weeks, 18.5% (24/130) from 29 to 31 weeks, and 0.6% (5/867) from 32 up to 37 weeks of gestational age. Fetal malformations had the greatest influence on neonatal mortality, as well as multiple pregnancies and preterm rupture of membranes (altogether 77.9%). Single and multiple gestations are concomitant with similar effects on neonatal mortality (6.2% vs. 8.7%). Only in 24.5% (249/1018) of the cases parenteral tocolysis was used; even in these cases tocolysis was terminated in 76% (189/249) because of the attainment of fetal maturity (70) or outcoming maternal (73) or fetal (36) pathology. Conclusion: As a result of the increase of intrauterine risks concomitant with the major pathologies (such as infection, placental malfunction, haemolysis, fetal malformation) and the low neonatal mortality and morbidity after 32 weeks of gestation, it can be assumed that in many cases termination of pregnancy will be a better decision for the obstetrician than its prolongation, and significant decrease of preterm deliveries cannot be reasonably expected in the near future.