Longitudinal outcome of a preterm birth: evaluation of an intervention program and an exploration of effects of maternal environment on preschool children born preterm

© 2013 Dr. Lisa Clare MilneWhile survival rates of preterm infants continue to improve, a significant number of surviving preterm infants display ongoing cognitive and behavioural problems. Environmental factors, including stress from medical and routine procedures in the Neonatal Intensive Care Unit (NICU) and problematic parent-infant interactions are now thought to influence developmental outcomes for preterm infants. The mother forms a large part of the infant’s environment and in the first 3 years of life environmental factors that may influence preterm infants include her relationship with the infant and also her capacity to organise, structure and regulate the infant’s interaction with other external experiences. In a landmark study (Nurcombe et al., 1984) found significant benefits emerging after 2 years on cognitive development (IQ )following early intervention in the NICU – the Mother Infant Transaction Program (MITP). The MITP is a relatively inexpensive parent-based program aimed at improving the neurodevelopmental outcomes for preterm infants. Study 1 was a follow-up at 36 months of 90 preterm infants, of less than 30 weeks gestation, who received either the intervention (a modified version of the MITP), or a control condition in a RCT. An ANOVA design was used with treatment entered as the fixed variable, and hospital and gender were entered as random variables. The results showed that there were no overall treatment effects on cognitive variables, executive function variables, or behavioural variables. However, the results were complex to interpret. In this field of study, where sample sizes are limited, consideration of the effect sizes is important, nonetheless the effect sizes in this study were unremarkable. While it may be that the results accurately reflect that at 36 months, the Premiestart modified MITP had no effect on the variables measured. Other possible explanations were that the preterm infants needed more time to recover and show the benefits of the intervention program, as shown in other studies where benefits emerged at later ages. Further it may have been that perhaps the measures were not sensitive enough to detect any differences between the groups, and finally it may be that improved standards of care in the NICU have reduced the impact of the intervention. It was also shown that the infants born at a later gestation, and who were less sick (as measured by length of hospital stay) had better cognitive achievement scores compared with the infants born earlier and who spent longer in hospital. Thus the MITP intervention may be effective only with very preterm infants, and not extremely preterm infants. Further follow-up research was recommended. Study 2 was one of the few reported studies exploring the relationship between maternal variables including: sensory profile, personality, maternal executive function and maternal emotion regulation on the neurobehavioural outcomes of preterm infants at 36 months, using a correlation-based design. Results showed that maternal executive functioning was highly correlated with preterm child executive functioning and behaviour. Maternal emotion regulation was also highly correlated with preterm child executive functioning and behaviour. A maternal sensory style of Low registration was predictive of preterm child behavioural outcomes. There were isolated correlations between maternal variables and preterm child cognitive outcomes. These findings were discussed in terms the theoretical framework of intersubjectivity, which is widely applied to understand infant mental health and development within the context of the relationship with the primary caregiver, and is consistent with the notion that the environment of the preterm infant/child is largely influenced by maternal behavioural characteristics. When planning interventions to assist preterm infants, consideration of maternal factors is warranted. It is possible that interventions could be more specifically targeted to address unique maternal characteristics