Pregnancy lasts approximately 9 months, however nature is not exact and all babies born between 37 and 41 weeks are considered to have been born at the correct time, i.e. to be a normal term delivery. Approximately 10% of babies are born early and whilst for some babies we can find a reason (multiple births, infections, maternal stress), about a third of premature births have no apparent explanation. When delivery occurs before the 37th week, the baby is called “premature”, if delivery occurs in the expected time but the baby is particularly small, that is under 2500g, it is called “Low Birth Weight”. Below you will find the most common terms used in the neonatal units to describe the newborn babies:
|By Gestational Age||Description|
|Term||A baby that is born between 37 and 41 weeks|
|Premature||A baby that is born between 37 and 28 weeks|
|Extremely Premature||A baby that is born before 28 weeks|
| By Birth Weight
|Low Birth Weight||A baby weighing between 2,500g and 1,500g|
|Very Low Birth Weight||A baby weighing between 1,500g and 1,000g|
|Extremely Low Birth Weight||A baby weighing less than 1,000g|
Premature babies have many special needs so, after delivery, many of them are taken care of in a neonatal intensive care unit (NICU). The NICU is an ideal setting for the baby providing warmth, nutrition, and protection while the baby grows and develops.
Premature babies have a high risk of developing illnesses such as breathing (respiratory) difficulties. In particular extremely premature babies may have respiratory difficulties due to the fact that the lungs are immature. These babies may develop a serious disease called Respiratory Distress Syndrome (RDS). In the following chapters you will find some useful information regarding the baby’s lungs and circulation, RDS and the role of surfactant is this disease.
It is important to note that nowadays due to many recent advances in neonatology, more than 90% of premature infants who weigh 1000g or more can survive, and even infants weighing as little as 500-700g have now a relatively good chance of survival, even though they may develop more complications.