2. A preterm baby's body and brain
A preterm baby is born before all of the organ systems are fully developed. Being born before 32 weeks of gestation usually means that medical support is needed to survive - these babies are cared for in a specialist neonatal unit. With good care the majority of babies born 24 weeks of gestation or above will survive.
View the video of neonatologist Professor Neil Marlow to hear more about how a preterm baby's body and brain develops.
Neonatologist Professor Neil Marlow describes how a preterm baby's body and brain develops
A preterm baby has all the organ systems they need at birth but many of them are relatively underdeveloped especially when birth occurs before 32 weeks of gestation. Babies can survive from as early as 23 weeks but the earlier birth occurs the greater the challenge they face. For example, at 24-26 weeks the skin is only 4-5 layers thick and not waterproof, the eyelids may not have separated, and the lungs are likely to need careful help and support to ensure that enough oxygen can get into the body. Over the last 20 years the neonatal team has become much better at doing this and as a result many more babies now survive. They may need help with a respirator or ventilator and be given oxygen for many weeks after birth. Once a baby gets to beyond about 29-30 weeks the need for support now becomes much less.
Alongside all the challenges faced by the baby, all of the body systems need to be looked after and this includes the brain.
The brain grows and changes rapidly up to 40 weeks of gestation. At 22 weeks, the brain is a smooth structure, the nerve cells in it are almost all in the position they will occupy later on, and many supporting cells are being produced and moving to their position. Subsequently the cells organise themselves and increase dramatically in size and number, folding the surface of the brain into the more familiar shape we see later in life.
Development of the brain for many babies progresses normally after preterm birth. Interference with the natural development of the brain can occur after preterm birth and a few babies have episodes of bleeding into the spaces inside the brain (called intraventricular haemorrhages). Only some of these babies may develop cerebral palsy or serious learning problems. Babies who are born extremely or very preterm are very more likely to suffer consequences of being born so early without showing serious disability.