Relationship of birthweight, maternal nutrition and infant mortality

A longitudinal study of the social and biological determinants of physical growth and mental development in rural Guatemala was started in 1969. A program was launched involving supplementation of pregnant mothers with a protein and calorie supplement ("atole") in 2 villages and another calorie supplement ("fresco") in 2 other villages. This paper presents an integrated quantitative approach to the analysis of data collected in the maternal supplementation program using 2 examples. The first example compares the effects of maternal height and weight at conception, and maternal caloric supplementation during pregnancy on birthweight. It was found that maternal childhood nutrition is as important a determinant of birthweight as is caloric supplementation during pregnancy. Similarly, the nutritional status of the mother during conception is as powerful a determinant of birthweight as is caloric supplementation during pregnancy. Past obstetrical history and maternal age do not affect these interrelationships among birthweight and maternal height, weight at conception, and maternal supplementation. The second example involves a consideration of postnatal function of the child, as well as several prenatal factors which affect infant mortality. Infant mortality in the study villages was found to be 4 times greater for babies with birthweight of 2.5 kg or less at term ("small for dates" babies; infant mortality rate, 121/1,000) than for heavier babies (infant mortality rate, 30/1000) (p0.05). By increasing maternal calorie supplementation during pregnancy, the number of babies weighing 2.5 kg or less was reduced from 20% among babies born to mothers ingesting less than 5000 calories during pregnancy to 5% among babies born to mothers who consume more than 20,000 calories during pregnancy. The findings suggest that village infant mortality can be lowered, and the birth of "small for dates" babies prevented by ensuring adequate levels of maternal nutrition during pregnancy. Efforts to improve maternal nutrition should start in childhood for optimum infant survival.