WOULD MORE CALORIES PER DAY KEEP LOW BIRTHWEIGHT AT BAY?

Abstract

Extremes of deprivation can be quoted to suggest that diet is important to the expectant mother. Average birthweight fell by about 500 gm during the siege of Leningrad in 1942 and by about 300 gm in Holland during the famine of 1944-45. Yet, in Motherwell, Scotland 1 obstetrician counseled mothers to eat a diet high in animal protein but low in carbohydrates and total caloreis. These mothers delivered infants some 400 gm lighter on average than those of Aberdeen mothers of similar stature and social class who ate normally. Thus, a recommended dietary regimen, which presumably maintained the mothers in good health, has been exceeded in its effect on infant birthweight only by the extreme famine conditions in Leningrad. Studies of the effect of dietary advice with or without specific food supplements have had varying results. Although the effects of diet on birthweight may be small, at least the data from different studies are reasonably consistent. This is not the case when perinatal and infant mortality are considered. In 1944 Balfour reported that the perinatal mortality rate was lower in infants of over 11,000 women in the poorer areas of England and Wales given extra dried milk and iron rich foods than in those of controls. Yet, in Rush's studies, additional dietary protein was associated with increased neonatal mortality. In the Institute of Nutrition of Central America and Panama (INCAP) study of Guatemala, infant mortality declined from 135 to 51/1000, but this fall was not obviously related to diet. The infant mortality rate was 5.4% in babies of women who had taken a supplement of less than 50 calories/day, 3.7% in infants of the group taking 51-100 calories, 6.5% in infants of the group taking 101-200 calories, and 3% in the group taking more than 200 calories. Behavioral sequelae consequent upon maternal diet are more difficult to assess. The effect of diet on infant behavior remains speculative at this time. Most dietary studies have concentrated on the possible benefits of giving mothers additional food during the 2nd half of pregnancy, by which time organogenesis is long since completed. If dietary supplements are to help prevent birth defects they must be begun before conception. Data from trials of preconceptional supplementation are few. A series of recent reports suggests that the use of additional vitamins may significantly reduce the risk of neural tube defects. In sum, extremes of nutritional deprivation do apparently reduce birthweight, but the extent by which birthweight is reduced should be kept in proportion.