Premature delivery
All children that are born before the 35th week after fertilization (37th WoP after the LMP) are considered to be premature deliveries. These children come into the world with still immature organ systems and functions. These can lead to a postpartum series of acute diseases and ensuing chronic pulmonary and neurological damage.
The respiratory distress syndrome (RDS) or hyaline membrane disease is a very typical complication of premature babies. It is due to the immaturity of the type 2 pneumocytes in the lungs, which have not yet been able to secrete enough surfactant, a product that promotes the unfolding of the alveoli during each breath. The absence of the surfactant causes the lung alveoli to stick together (secondary atelectasis). The required long-term ventilation of a premature baby and oxygenation in the air being breathed in, can lead to the development of a chronic lung disease, the bronchopulmonary dysplasia (BPD) and eye damage: retrolental fibroplasia (retinopathy of prematurity). Exogenous administration of synthetic surfactant reduces the severity of RDS and neonatal mortality.
The survival chances of a premature baby with a weight at birth of less than 1500 gm has improved significantly in the last decade. Today it is assumed that more than 50% of those born prematurely with a weight at birth between 600-1000 gm and more as well as 85% of all premature babies with a weight at birth between 1000-1499 gm survive.
One distinguishes between eutrophic and hypotrophic premature babies. For this classification growth and weight curves are applied that, with the help of measurements made available in the respective population groups, display statistically their normal distributions.
The intrauterine weight measurements are based on extrapolated values of various diameters obtained with ultrasound (green). They do not correlate exactly with the postnatal weight measurements.
One distinguishes three phases in the weight distribution curve: the intrauterine period, the transition period (or the perinatal period – the first 6 - 12 days) and the extra-uterine period (from 6 - 12 days following delivery).