The effect of antenatal betamethasone on cord blood concentrations of retinol-binding protein, transthyretin, transferrin, retinol, and vitamin E.

We assessed the effect of short-term (less than or equal to 1 week) and prolonged (greater than 1 week) exposure to antenatal betamethasone on umbilical cord serum concentrations of retinol-binding protein (serum t 1/2 = 12 h), transthyretin (t 1/2 = 2 days), transferrin (t 1/2 = 8 days), retinol (vitamin A), and vitamin E in appropriate-for-gestational-age preterm newborn infants of less than 36 weeks' gestation. A group of 30 infants whose mothers received a single course of betamethasone less than or equal to 1 week prior to delivery had significantly elevated mean retinol-binding protein and transthyretin but not transferrin concentrations when compared with a group of 30 gestational age- and birth weight-matched infants with no exposure to antenatal betamethasone. A group of eight infants whose mothers received multiple (more than two) weekly courses of betamethasone prior to delivery had significantly elevated mean serum concentrations of all three proteins when compared with eight gestational age- and weight-matched control infants with no betamethasone exposure. Serum retinol and vitamin E concentrations were measured in a group of 21 infants exposed to short-term prenatal betamethasone and were significantly greater than in a group of 21 control infants without steroid exposure. We conclude that antenatal steroids increase the umbilical cord serum concentrations of retinol-binding protein, transthyretin, transferrin, retinol, and vitamin E. The effect on the various serum proteins is dependent on the duration of exposure to steroids.

A comparison of the mid-arm circumference/head circumference ratio and ponderal index for the evaluation of newborn infants after abnormal intrauterine growth.

We studied the accuracy of the ponderal index and the mid-arm circumference/head circumference ratio for detecting newborn infants who were likely to be symptomatic because of aberrant intrauterine growth. Sixty infants were evaluated because of suspected intrauterine growth retardation; both the mean ponderal index and mid-arm circumference/head circumference ratio were significantly lower in the group of 30 symptomatic infants than in the group of 30 asymptomatic infants (p less than 0.05). However, the mid-arm circumference/head circumference ratio identified a significantly higher percentage of the symptomatic infants than the ponderal index (80% vs. 47%; p = 0.007). An additional 60 infants were evaluated because of suspected abnormal intrauterine growth acceleration. The mean mid-arm circumference/head circumference ratio, but not the ponderal index, was significantly higher in the group of 30 symptomatic infants than in the group of 30 asymptomatic infants (p less than 0.005). Again, the mid-arm circumference/head circumference ratio identified a significantly higher percentage of the symptomatic infants than the ponderal index (79% vs. 33%; p less than 0.001). The mid-arm circumference/head circumference ratio is more accurate than the ponderal index for the evaluation of potentially symptomatic newborn infants who suffered abnormal fetal growth. The ponderal index is not useful for the detection of symptomatic large-for-dates infants.

Cord transferrin and ferritin values in newborn infants at risk for prenatal uteroplacental insufficiency and chronic hypoxia.

We measured cord transferrin and ferritin levels in 50 newborn infants with fetal conditions associated with either uteroplacental vascular insufficiency or chronic hypoxia. Sixteen small for gestational age infants, 21 infants of mothers with preeclampsia, and 13 symptomatic infants of diabetic mothers had significantly higher transferrin levels and lower ferritin levels and calculated iron stores than did asymptomatic gestational age-matched control infants without these conditions. Cord ferritin levels and calculated iron stores were significantly lower in the infants of diabetic mothers than in any other group of infants. Cord transferrin levels were inversely correlated with ferritin levels (r = -0.59, P less than 0.001) and were unrelated to transthyretin levels and birth weight in the high-risk infants, but were positively correlated with ferritin levels (r = 0.50, P less than 0.001), transthyretin levels (r = 0.65, P less than 0.001), and birth weight (r = 0.75, P less than 0.001) in the control infants. We conclude that cord transferrin levels do not reflect protein-energy status in newborn infants with prenatal histories suggesting uteroplacental insufficiency or chronic hypoxia, and that when associated with decreased cord ferritin levels, indicate possible impaired iron stores in these infants.