The risks of later problems and the effect of neonatal care for premature infants

Premature infants are at risk for problems in a variety of areas. The later the infant is born, the lower the risk of later problems. Results of the largest long-term study of babies born extremely prematurely at the age of 25 weeks or fewer were published in the New England Journal of Medicine in 2005. When the children were assessed at age 2 1/2 results showed that 50% had no disabilities, 25% had some level of disability and 25% had severe disability. Results of follow-up at age 6 ½ showed a high rate of disability; 22% had a severe disability such as inability to walk caused be cerebral palsy, very low cognitive ability, blindness or deafness. A further 24% were moderately disabled with cerebral palsy (but walking), IQ in the special needs range and lesser problems with hearing and vision. Milder problems such as wearing glasses, a squint or low/normal cognitive scores were shown by 34% of children. Twenty percent of the very premature babies had no problems. According to Neil Marlow, joint author of the paper "These results show that the majority of children do not have a serious physical disability, i.e., do not have cerebral palsy, blindness or deafness, and despite the high incidence of learning difficulties, half are doing reasonably well and keeping up with their classmates."

 

Events that influence genetic composition or the structure and function of the brain can affect later development. The most significant risk factors include:

• the prenatal environment: e.g. cigarette smoking, substance abuse, infection
  neonatal complications: e.g. loss of oxygen, intraventricular hemorrhage, types of Neonatal Intensive Care Unit (NICU) experiences
• chronic factors: e.g. mother-infant interaction, post natal nutrition, hydrocephalus, blindness, deafness

The areas that have been shown to be most likely affected include:

• cognitive and academic ability e.g. math or reading disability, intellectual ability)
  language (e.g. delays)
• fine and gross motor (e.g. poor coordination)
• vision, hearing (e.g. visual impairment)
• mental illness (e.g. attention-deficit/hyperactivity disorder)
• The disabilities can range from relatively minor, such as difficulty catching a ball due to poor eye hand coordination, to more significant or global disabilities such as blindness, with the type and severity dictating future intervention.

The effect of neonatal care on later development
The type of care required by the infant in the NICU to improve physical functioning may impact later development. For example, the infant who has difficulty breathing may need frequent placement of a breathing tube. The infant who receives this repeated unpleasant touch in the area of the mouth may develop oral motor sensitivity or oral motor muscle problems that can affect later speech and language development. Further, if the infant isn't appropriately supported during these stressful medical procedures with positive touch, pressure in the brain may increase causing the fragile blood vessels in the brain to burst. This can lead to intraventricular hemorrhage (IVH), resulting in neurodevelopment problems in the future.

Positioning the preemie can also influence future development. For example, preemies may be routinely left to lie on their backs, a position that differs from the natural curved fetal position they would maintain in utero. This can result in a shortening of the scapula muscles between the shoulder blades, causing a restricted range of motion and later motor problems. Thus, the older infant may be unable to appropriately reach for objects in front of him.

 

Researchers believe the different physiological systems are affected both positively and negatively by early NICU experiences. Imagine the seemingly simple and common NICU experience of giving a preemie a heel stick (for a blood test). People may be talking over the infant who is under bright lights. Different internal systems are stimulated simultaneously causing the infant to become overwhelmed. Typically, due to the overload, the infant is unable to soothe himself and restore a calm state. As a result of overload, the infant may (a) dissociate (tune out the painful or confusing situation), (b) become defensive in one area (be hypervigilant and on guard when stimulated) or (c) become distractible (trying desperately to switch from one stimulated area to another in an effort to manage the assault on the different areas of the system). Therefore later in life, when faced with multiple tasks or input, seemingly simple tasks such as listening to the teacher while she is writing on the board or putting on a jacket amongst a group of young children, can overwhelm the child's coping ability.

 

New understanding of the impact of the physical environment on later development has led to new interventions and devices.

 

Correctly sized diapers is one such simple invention. For example, it was found that preemies who are put in diapers that are too large must keep their legs spread apart in order to accommodate the extra fabric. This resulted in incorrect turn out of the hips and thus later motor problems.

A form of holding called Kangaroo Care is being practiced and taught to parents in many NICUs. This special holding has parents hold the infant on their chest allowing for skin-to-skin contact. Results have shown that "the parent's body temperature adjusts to keep the baby's temperature at the right level. The baby's breathing also becomes more even, and the heart rate and blood oxygen levels stay steady."