Babies With Moderately Low Birthweight Are At Risk Of Neurological Immaturity

Main Category: Pediatrics / Children's Health
Also Included In: Neurology / Neuroscience
Article Date: 11 Nov 2009 - 1:00 PDT

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Low-birthweight babies, until now considered at low risk, have less sharp reflexes, diminished responses to visual and auditory stimuli and other neurological impairments such as attention deficit, difficulty adapting to their environment and reduced motor skills compared with normal-birthweight babies.

The most widely held view in the medical community is that moderately low birthweight is a variation of normality. These fetuses are generally believed to be "constitutionally small" and are therefore not considered at risk. A study performed at Hospital Clínic de Barcelona by Francesc Figueras and Eduard Gratacós of the Department of Maternal-Fetal Medicine and researchers of the Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS) and recently published in Pediatrics shows that this belief could be erroneous and that these babies show neurological immaturity from birth. Some of the neurological disorders affecting these infants are attention deficit, difficulties adapting to the environment and reduced mobility compared with normal-birthweight babies.

The study evaluated the neurological skills of 100 normal-birthweight babies and 102 "small-for-gestational-age" infants, with a birthweight lower than the 10th percentile and normal placental function (umbilical artery pulsatility index below the 95th percentile). Low-birthweight babies had lower scores on the Neonatal Behavioral Assessment Scale (NBAS), which evaluates neurological capacities in neonates, such as attention, mobility, response to visual and auditory stimuli, social and environmental adaptation. Infants with low birth-weight systematically showed poorer results on all the neurological competencies analyzed, suggesting that these babies suffer delayed neurological maturation with possible repercussions on their future sensory and cognitive development, especially at school and during adolescence.

Until now, the risk of impaired neurological development was known for babies with severe growth delay, affecting less than 1% of pregnancies and mainly premature infants. However, mildly affected fetuses that are close to term (up to 10%) are considered a variation on normality. The Barcelona study shows that there is a risk of neurological delay even if the results of current tests are normal and questions the use of techniques such as umbilical artery Doppler ultrasonography, currently the standard procedure to distinguish fetuses with true growth delay from those that are simply small but without growth restriction. The study reveals that new tests are required to detect these at-risk babies.

The research performed in Barcelona is important because neurodevelopmental disorders affect up to 10% of the pediatric population and as many as two-thirds of these disorders could be explained by fetal diseases or abnormalities, although these entities are poorly understood. The results of the Barcelona study strongly support the hypothesis put forward several years ago by researchers at Hospital Clínic de Barcelona that a proportion of childhood neurological disorders could be explained moderately low birthweight. Identifying babies at risk of neurological deficits as early as possible might prevent subsequent cognitive impairments. One of the study's applications would be to establish special early detection and treatment programs, a possibility intensively looked into by Hospital Clínic de Barcelona in collaboration with other centers. Early diagnosis and treatment would improve cognitive development, learning, and social integration in infants with neurological problems.

Source
Institut d'Investigacions Biomèdiques August Pi i Sunyer

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