The results of two studies of the influence of moderate maternal malnutrition on the weight and chemical characteristics of the placenta are discussed. In the first study, two groups of pregnant women of high and low socioeconomic status from Guatemala City were studied. Socioeconomic status was defined by family income, educational level of the mother, and environmental sanitary conditions. Both groups were very similar with respect to age, parity, gestational age, and absence of severe disease during pregnancy. The average placental weight in the low socioeconomic group was 15 per cent below that of the high socioeconomic group and there was a consistent association between the postpartum maternal weight and placental weight. There were no differences between the two groups regarding placental concentration of fat, protein, water, ash, hemoglobin, and DNA; hydroxyproline and fat concentration were significantly lower in the low socioeconomic group. The hypothesis that the difference in placental weight observed between the two groups was primarily due to maternal nutritional status was tested in the second study by means of nutritional intervention in four rural villages in Guatemala. Two of the villages received a protein-calorie preparation while the other two received a calorie supplement. Placental weight was higher among women with high levels of supplemented calories during pregnancy, independently of the type of food supplement ingested. On the average, the groups with low caloric supplementation (smaller than 20,000 calories) had placental weight 11 per cent below those with high caloric supplementation (larger than or equal to 20,000 calories), In contrast to placental weight, the concentration of placental chemical components studied was not associated with caloric supplementation. It was concluded that moderate protein-calorie malnutrition during pregnancy leads to lower placental weight without significantly changing the concentration of the biochemical components studied. The reduction of placental weight may be the mechanism by which maternal malnutrition is associated with high prevalence of low-birth-weight babies in these populations.
PIP: The results of 2 studies carried out at the Institute of Nutrition of Central American and Panama are described. The 1st study was of an urban population and the other in rural villages. The influences of mode rate maternal malnutrition on the weight of the placenta and its chemical characteristics were particularly studied. Placentas were homogenized and then divided into 3 equal parts which were lyphilized. In the urban study, women of high and of low socioeconomic status were compared. The low socioeconomic group was considered to suffer from calorie deficiency, and particularly protein malnutrition at the time of the study. The values of the tricipital skinfold tests were lower in this group, and the weight for height ratio was low (p less than .01). The average placental weight in the low socioeconomic group was 15% below th at of the high socioeconomic group. Placental concentrations of protein, water, ash, hemoglobin, and DNA were the same in the 2 groups, while hydroxyproline and fat levels were less in the low socioeconomic group, and peripheral villi areas of the placenta were shown to be less in this group (p less than .001). These changes were attributed to moderate maternal malnutrition. In the rural study the female populations of 4 villages were investigated. Mean weight gains during pregnancy were only 60% of normal. Diet consisted mostly of corn and beans with little animal protein. In 2 villages, a dietary supplement containing protein was distributed and in the 2 other villages another supplement without protein and of lower caloric value was given. Placental weights were 11% less in those with the lower caloric and no protein supplement. An association between maternal malnutrition, placental weight, and birth weights of infants was shown. Low placental weight was considered to be the most important measurable factor in reducing birth weights.