The Classification of the Low Birth-weight Infants from the Viewpoint of Mental Development

Periodical checkups on 206 infants were carried out in order to elucidate which of various factors would pose decisive influence upon the retardation of mental development after birth with the AIKEN method. Correlations between average DQ (development quotient) and figures of physical measurements at birth were sought after. Consequently, weeks of gestation, body weight, cephalic circumference and body length at birth revealed certain correlation with the retardation of mental development. Multiple regression analysis disclosed highly significant correlations of body length and cephalic circumference toward the birth weight. Therefore, both weeks of gestation and birth weight are the direct contributory factors to average development quotient. Based on this result, a prediction equation for the mental development after birth has been proposed. Low average DQ was found in high percentages among infants born with toxemia of pregnancy or premature rupture of membranes. However, it is suggested that they are not the direct causes of such retardation, but are rather provoking short weeks of gestation and low birth weight. In summary, the newborn with less than 37 weeks of gestation and below 2,000 grams of birth weight would be named and classified as a SFD (small for dates) with the problem for mental development (MD-SFD).