Faculty Bibliography

Umbilical cord blood levels of lactate, base deficit, and pH were measured in 452 liveborn infants. In vigorous newborns, the mean umbilical arterial and venous concentrations of lactate were lowest with elective cesarean section, higher with cesarean section performed during labor, and highest with vaginal delivery (P less than .001). This suggests a rise in the fetal lactate level in response to labor. However, there was no concomitant increase in the mean umbilical arteriovenous lactate differences, indicating that both fetus and placenta increase their lactate production proportionately with labor. Depressed newborns had higher umbilical lactate levels than vigorous newborns irrespective of the method of delivery (P less than .001). Depressed newborns also had a higher mean umbilical arteriovenous lactate difference than vigorous newborns (P less than .001). This suggests that, under conditions that lead to neonatal depression, the fetus is the major source of the increased lactate produced, with a smaller contribution from the placenta. The fetal lactate level may be a good indicator of fetal stress in labor

Simultaneous measurement of fetal heart rate (FHR), uterine contractions (UC), continuous fetal tissue pH (TpH) and transcutaneous pO2 (tcpO2) was attempted in 40 high-risk parturients monitored for an average duration of 117 +/- 74 min. There were only two failures (9%) in the last 23 cases, with satisfactory recording of all parameters in 78% of the total. At present, the feasibility of simultaneous biochemical monitoring is limited to the active phase of labor. Fetal scalp and umbilical arterial blood pH and pO2 were obtained as well. The biochemical data showed a good correlation between tcpO2, scalp capillary pO2 and umbilical artery pO2 (P less than 0.02). The correlation was not significant between similar pH comparisons, although an average difference of 0.04 pH units was observed between the final tpH and umbilical artery pH. Both fetal TpH and tcpO2 fell progressively during labor. Preliminary findings comparing TpH, tcpO2 and FHR suggest that changes in tcpO2 rapidly reflect changing maternal and fetal conditions, while TpH responds more slowly and less sensitively

Estriol (E3), the most abundant estrogen in pregnancy is produced predominantly in the placenta from androgen precursors of fetal origin. The estriol so formed is secreted efficiently into the maternal circulation where it is converted to 4 conjugates--estriol-3-sulfate (E3-3S), estriol-16-glucosiduronate (E3- 16G ), estriol-3-glucosiduronate (E3- 3G ) and estriol-3-sulfate-16-glucosiduronate (E3-SG). The order of renal clearances is E3- 16G greater than E3- 3G greater than E3-3S approximately E3-SG. Unconjugated E3 and E3- 3G differ from the other forms of estriol in that their removal from the blood compartment is essentially irreversible. E3-3S, E3- 16G and E3-SG undergo interconversions during enterohepatic circulation and eventual partial conversion to E3- 3G . Following delivery of the fetus and placenta, unconjugated E3 is no longer detectable in the maternal serum within 1-2 h, whereas the concentrations of the conjugates decline more slowly, the rates being determined by the rates of renal clearance and enterohepatic interconversions. E3- 3G levels were dramatically elevated in a case of Group C polycystic kidney disease, providing evidence that this conjugate is indeed an end-product of estriol metabolism.

This study attempts to determine the major source of lactate in the normal and in the depressed human fetus, in order to assess the applicability of fetal blood lactate measurement for the evaluation of fetal stress during labor. We obtained umbilical arterial and venous blood samples at delivery in 132 liveborn infants, together with simultaneous maternal radial arterial samples. All samples were analyzed immediately for pH, blood gases, and lactate. In vigorous newborns (1-minute Apgar score greater than or equal to 7), umbilical arterial and venous lactate levels were lowest with elective cesarean section done before the onset of labor, higher with cesarean section performed during labor, and highest at the time of vaginal delivery (p less than 0.001, Tab. I). Fetal lactate levels were also significantly higher than maternal levels in vigorous newborns (p less than 0.01), the lactate difference between umbilical artery and maternal artery being lowest with elective cesarean section, higher with cesarean section performed during labor, and highest with vaginal delivery (p less than 0.02, Tab. II). Depressed newborns (1-minute Apgar score less than 7) had higher umbilical lactates and higher fetal-maternal lactate differences than vigorous newborns (p less than 0.01, Tab. III). Our results indicate that the blood lactate levels in both mother and fetus increase with labor and reach their highest values at the time of vaginal delivery. The lactate levels are highest in the umbilical artery, lower in the umbilical vein, and lowest in the maternal artery before the onset of labor.(ABSTRACT TRUNCATED AT 250 WORDS)

Real time ultrasound was used to evaluate the anatomy of the fetal brain at different gestational ages. Anatomical correlation with the gross brain was utilized for more accurate identification of the neuroanatomical structures. The normal growth of the ventricular system was studied. Transaxial measurements of the anterior horn (AH) and maximum ventricular length (MVL) and width (MVW) were made, and enlarged as pregnancy progressed. The ratios of MVW/MVL, MVL/BPD, and MVW/BPD provide guides to the early diagnosis of hydrocephalus and intracranial abnormalities. Specific measurements of the cerebral ventricles at various gestational ages may be made accurately by utilizing the anatomical landmarks. The anterior horn and midbrain measurements are of little value in the early diagnosis of hydrocephaly. Maximum ventricular length and width are the most useful determinants of hydrocephaly, even as early as 20 weeks. A set of discordant twins in which twin B was found to be hydrocephalic by these studies in the twentieth week is presented with serial measurements for both twins. Multiple measurements of the cerebral ventricular system in utero permit early and precise diagnosis of fetal hydrocephaly