Fetal growth retardation in relation to maternal smoking and weight gain in pregnancy

Abstract

Two types of fetal growth retardation were recognized in term infants. One type was characterized by an abnormally low ponderal index (defined as birth weight in grams X 100 divided by crown-heel length in cubic centimeters.) The other type of growth-retarded infants had abnormally short crown-heel lengths for fetal age. Both types were observed under all conditions studied. However, mothers who smoked cigarettes during pregnancy were more likely to have infants with short body lengths for dates, whereas mothers who had low weight gain in pregnancy were more likely to have infants with low ponderal indices. Social group, prepregnancy weight, parity, marital status, and fetal sex were found to be less determinant of fetal growth than were maternal weight gain and smoking habits.

PIP: 2 types of fetal growth retardation were recognized in term infants delivered to more than 1200 white mothers with uncomplicated pregnancies from 1973-1974. The 1st type was characterized by an abnormally l onderal index (PI), defined as birth weight in grams times 100 divided by crown-heel length in centimeters. The other type had abnormally short crown-heel lengths for their fetal age. Both types were observed under all conditions observed (maternal smoking/nonsmoking, low/greater weight gain, and high/low social class). However, mothers who smoked cigarettes during pregnancy were more likely to have infants with short body lengths for fetal age, whereas mothers who had low weight gain in pregnancy were more likely to have infants with low PIs. Social group, prepregnancy weight, parity, marital status, and fetal sex were less determinant of fetal growth than were maternal weight gain and smoking habits. Very few growth-retarded infants were identified by routine procedures for checking the progress of pregnancy and labor. Support for the idea that the 2 types of growth retardation are distinct is given by the fact that they follow different developmental paths after birth; the low-PI babies catch up to normal babies in weight and development within 3-6 months; short-for-fetal-age babies have a notable incidence of organic disease and continue to grow on the same low percentiles for height and weight as they do in utero.