The cerebral uptakes of glucose, oxygen, lactate, pyruvate, acetoacetate and beta-hydroxybutyrate were compared in the adult, the fetal, and the newborn sheep. Beginning 1-2 days after surgery, we withdrew samples simultaneously from an artery and from the sagittal sinus for up to 2 wk. At all ages glucose was the only substrate taken up in significant quantity relative to oxygen. The glucose-oxygen quotients were 0.98 less than 1.03 less than 1.08 in adults; 0.92 less than 0.99 less than 1.06 in lambs; 0.92 less than 0.98 less than 1.03 in fetuses. These quotients were not significantly different. There was a significant (P less than .05) arteriovenous difference for lactate in the adult (-0.031 mM), but not in the lamb or fetus. A significant (P less than .05) arteriovenous difference pyruvate was found in the adult (-0.013 mM) and in the fetus (-0.020 mM). The findings of a glucose-oxygen quotient of approximately 1 and the lack of significant lactate production in fetal sheep brain are consistent with the hypothesis that anerobic glycolysis is unimportant to the steady-state cerebral metabolism of the fetal sheep.

Records on 16,458 consecutive births were examined to determine associations between the respiratory-distress syndrome of the newborn and cesarean section, maternal diabetes, ante-partum hemorrhage, toxemia of pregnancy, low one-minute Apgar scores and prolonged rupture of fetal membranes. Groups of infants were compared by four-week gestational age blocks. One-minute Apgar scores of less than 5 and of less than 8 were associated with a significant ( less than 0.05) increase in the incidence of respiratory-distress syndrome at gestational ages beyond 30 weeks. Cesarean section was associated with a significant increase after 34 weeks of gestation. There was no association between the syndrome and toxemia of pregnancy, ante-partum hemorrhage or prolonged rupture of fetal membranes. These data do not support the hypothesis that there is a lower incidence of the respiratory-distress syndrome in infants born after prolonged rupture of fetal membranes.

Mammary blood flow was measured in conscious, unanesthetized ewes with electromagnetic flow probes prior to spontaneous labor (four animals) or during the induction of premature labor (four animals) by administration of dexamethasone, 1 mg/24 h, to the fetus. In all animals an increase in mammary blood flow was noted prior to delivery. Dexamethasone administered to one mother in the same dose did not induce labor or produce an increase in mammary blood flow. These results suggest that the fetal adrenal gland influences maternal mammary blood flow prior to delivery.