Developmental surveillance of childen born preterm
Babies born prematurely are particularly vulnerable to delays in their development. In their first weeks of life preterm babies are going through developmental processes that occur in the uterus for full term babies and adapting to life outside the uterus before they are developmentally ready. Their ability to, for example, breathe, feel, hear and see are impacted by stimuli whilst these organs are still immature. This can alter the development trajectory and neuronal connections and affect abilities later.
The development timescale and corrected age
The rate of development is rapid in the first two years of a baby’s life, and not accounting for prematurity will cause a child to appear to have falsely delayed development.
For example, a preterm baby born at 30 weeks gestational age will only be able to behave in a similar fashion to a full term (40 weeks) newborn when it reaches 10 weeks of age. This is called the corrected age.
The corrected age of a preterm baby is calculated from the original date the baby was due - the expected date of delivery - and their chronological age from the actual date of their birth. Corrected age should be used until a child born preterm is at least two years of age.
Age terminology during perinatal period
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Development milestones and surveillance for children born preterm
There is evidence to suggest that preterm infants can reach development milestones later than term infants even after correcting for their prematurity. However, the risk of delayed development is greater the more preterm a child is, and many have entirely appropriate development for their corrected age.
Children’s developmental milestones occur in an ordered fashion over time, for example, a child must learn to sit before they stand, and stand before they walk. This gives opportunities for strategies to encourage development, knowing what to expect at the next stage.
Developmental milestones are divided into broad categories:
- Motor - fine motor and gross motor
- Language - receptive and expressive
- Social and emotional
- Sensory - vision, hearing
A number of national guidelines recommend developmental surveillance for all high-risk infants up to the age of 4 years but there may be further developmental difficulties that only become evident as the child continues to grow and learning becomes more complex.
In the United Kingdom, children born preterm can enter school based on their expected date of delivery rather than their date of birth. This prevents them starting school a year earlier than their genetic potential. In particular, the EPICURE studies have shown that children born preterm who have normal development at two years of age may still have educational needs at six and eleven years. For individual preterm children the trajectory of their development over time may be more helpful than whether they are meeting milestones at a particular point in time.
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