3RD TRIMESTER FETAL GROWTH AND MEASURES OF CARBOHYDRATE AND LIPID-METABOLISM IN UMBILICAL VENOUS-BLOOD AT TERM

Aim-To compare measures of carbohydrate and lipid metabolism in umbili cal venous blood after birth at term in pregnancies with normal and re tarded fetal growth during the third trimester. Methods-Three groups o f pregnancies reaching term, in which fetal growth had been prospectiv ely monitored by repeated ultrasound measurements during the third tri mester, were studied. Sequential fetal abdominal circumference measure ments remained above the 10th centile in 42 (normal size, normal growt h group), below the 10th centile but did not depart further than 1.5 S D (small, normal growth group), or below the 10th centile and subseque ntly fell away by more than 1.5 SD before delivery (small, growth reta rded group). Birthweight, neonatal morphometric measures (ponderal ind ex, mid arm:head circumference ratio, subscapular and triceps skinfold thickness),umbilical venous blood concentrations of glucose, insulin, pro-insulin, des 31,32 proinsulin, total cholesterol, free cholestero l, cholesterol ester, triglycerides, lipoprotein (a), apolipoprotein A -1 and apolipoprotein B were measured. Results-The median birthweight of the three groups was significantly different (3570, 2569, and 2277 g, respectively). Median values of ponderal index and mid arm:head cir cumference ratio were significantly lower in the small, growth retarde d group and did not differ between the small and normal size groups wi th normal growth. Both groups with small fetuses had significantly low er mean glucose and cholesterol ester concentrations, and higher mean free cholesterol:cholesterol ester ratios, compared with the normal si ze, normal growth group. The group showing fetal growth retardation ha d mean total cholesterol and mean cholesterol ester concentrations tha t were significantly lower than those of both the other two groups. Me an des 31,32 proinsulin concentrations were low in both groups of smal l fetuses, but only significantly so in the group without fetal growth retardation. Mean insulin, proinsulin, free cholesterol, triglyceride s, lipoprotein(a), apolipoprotein A-1, apolipoprotein B concentrations and the ratio of A-1:B were similar in all three groups. Conclusion-T he similarity in the umbilical venous blood carbohydrate and lipid pro file at term between pregnancies with documented third trimester fetal growth retardation and those with ''genetically'' small babies argues against a major role for intrauterine nutritional deprivation as a ca use for the association between birthweight and subsequent adult disea se.