Effects of vascular insufficiency on placental ribonuclease activity in the rat

Activity of alkaline RNase in placentas of malnourished women

Pregnancies were compared in 18 Ecuadorian women of low socioeconomic status and 11 of high socioeconomic status. Objective evidence of malnutrition was demonstrable in virtually all of the women from the low socioeconomic group and in none from the high socioeconomic group. Birth weight and placental weight were significantly lower in the malnourished group. Nucleic acid and protein content of placentas were slightly lower and activity of alkaline ribonuclease was markedly elevated. The data reinforce animal studies and demonstrate for the first time in human subjects that alkaline RNase activity is increased in placentas from malnourished women. We suggest that activity of this enzyme in placenta may prove to be a useful marker of maternal and fetal nutritional status.

Maternal malnutrition, low birthweight and related phenomena in man. Physiological and behavioral interactions

The variables producing lowered birthweight include prematurity, maternal genetic tendencies, low prepregnancy weight, low weight gain during pregnancy, pathologies of pregnancy, multiple births, maternal malnutrition, and intrauterine growth retardation. Reductions in intelligence related to low birthweight are distributed equally among different socioeconomic groups. However, when mental subnormality is used as the criterion of impairment, low socioeconomic status is a better predictor of poor outcome than low birthweight. Even when general intelligence is not impaired, low birthweight children show specific cognitive, perceptual and behavioral signs of organic brain damage. In the absence of frank congenital abnormality, absolute birthweight is a better predictor of impaired intelligence than intrauterine growth retardation. Maternal malnutrition during the period of pregnancy does not influence offspring intelligence. Malnutrition throughout the maternal and offspring lifespan does impair intelligence, especially when surrounding social conditions are counterproductive to its development.