The relationship of maternal and fetal glucose concentrations in the human from midgestation until term.

The relationship between maternal and fetal glucose concentrations was investigated in pregnant women at different gestational ages. Maternal and fetal blood samples were obtained during 14 fetoscopies (17 to 21 weeks), four umbilical cord samples (32 to 36 weeks), nine elective cesarean sections with appropriate for gestational age (AGA) fetuses (35 to 39 weeks) and nine elective cesarean sections with small for gestational age (SGA) fetuses (34 to 37 weeks). A significant linear relationship between maternal and fetal glucose concentrations was demonstrated at midgestation (P less than .001) and at late gestation (P less than .001). At equal maternal concentrations there were no significant differences in fetal glucose concentration between the cord samples obtained in late gestation and those obtained at cesarean section. At midgestation fetal glucose concentration is independent of and may exceed maternal concentration at maternal glucose levels less than 4.44 mmol/L. Furthermore, the relationship between maternal and fetal concentrations at maternal glucose concentrations greater than 4.44 mmol/L is significantly different at midgestation from that at late gestation (P less than .01); at equal maternal concentrations there were higher glucose concentrations in the mid trimester fetus. In late gestation as the maternal glucose concentration increases there is an increase in the maternal arterial-umbilical arterial glucose concentration difference and the umbilical glucose/oxygen quotient (P less than .003) reflecting increased glucose utilization by the fetus. There were no significant differences between AGA and SGA babies with respect to these relationships.

Foetal pulmonary maturation in pregnancies complicated by diabetes and Rh immunization.

In pregnancies complicated by diabetes, foetal lung maturation depends on a good control of maternal blood glucose values. In poorly controlled maternal diabetes, foetal hyperinsulinaemia may cause a delay in pulmonary maturation. There was no single case of respiratory distress syndrome (RDS) in 112 pregnant class B-F diabetic patients that we treated with high doses of insulin. Furthermore, in a controlled randomized trial of diet versus insulin treatment in class A diabetes we found no differences in perinatal mortality in patients with adequate metabolic control. In pregnancies complicated by Rh isoimmunization, determination of phosphatidylglycerol in amniotic fluid is a more reliable marker of foetal lung maturity than is the lecithin/sphingomyelin ratio. The marked decrease in perinatal mortality due to Rh incompatibility observed in recent years depends on several factors including administration of corticosteroids to the mother to prevent RDS, irrespective of whether amniotic fluid parameters indicate foetal lung maturity.

Pregnancy in women with chronic renal failure.

We describe 19 pregnancies in 18 women with chronic renal disease and plasma creatinine greater than or equal to 1.6 mg/dl before pregnancy. There were 2 spontaneous abortions (11th and 21st week), 2 therapeutic abortions (18th and 19th week), 1 stillbirth (30th week), 1 neonatal death (31st week) and 13 live births, 7 of them were preterm. Nine cesarean sections were done. Serial determinations of plasma creatinine during pregnancy showed a trend to decrease during the first half and to increase during the second half of pregnancy. The effect of pregnancy on the progression of renal failure was evaluated in 14 patients by comparing the linear regression lines of reciprocal plasma creatinine versus time before and after pregnancy. In 5 patients the rate of progression worsened after pregnancy. Our data indicate that women with chronic renal failure may have a successful pregnancy, but one third of them will have an accelerated rate of progression of the disease.

Sickle cell thalassemia in pregnancy: a case report.

A 31-year-old pregnant woman at 20 weeks' gestation was sent to our hospital for fever, anemia, and arthralgias. As she was known to be a double heterozygote for beta-thalassemia and hemoglobin S, a diagnosis of hemolytic anemia caused by sickled red cells vasocclusive crises was made. The patient was submitted to partial exchange transfusion (PET) with a complete recovery. A second PET was performed at 36 weeks' gestation, and elective cesarean section was performed at 37 weeks, with the birth of a normal female neonate.

Umbilical amino acid concentrations in appropriate and small for gestational age infants: a biochemical difference present in utero.

Plasma amino acid concentrations were determined in 28 pregnant women and their infants at term. Samples were obtained from 17 appropriate for gestational age and eight small for gestational age infants at cesarean section, while three small for gestational age fetuses were studied in utero by transabdominal cord sampling by means of ultrasonic guidance. Small for gestational age fetuses have significantly lower concentrations of alpha-aminonitrogen, compared with those of appropriate for gestational age fetuses, in both the umbilical artery and vein. Most of the difference is accounted for by the branched chain amino acids valine, leucine, and isoleucine. In contrast, hydroxyproline concentration is significantly higher in both the umbilical artery and vein of small for gestational age fetuses. The sum of the branched chain amino acid concentrations in the umbilical vein is directly related to maternal arterial values in both appropriate for gestational age and small for gestational age fetuses. Maternal arterial concentrations were slightly lower in small for gestational age fetuses and the regression analysis of umbilical venous versus maternal arterial branched chain amino acid concentrations was significantly different for small for gestational age and appropriate for gestational age infants. Umbilical venoarterial concentration differences in normal fetuses are significantly positive for most essential amino acids and for total alpha-aminonitrogen. In contrast, these differences were significant only for four essential amino acids in small for gestational age infants, while the total alpha-aminonitrogen venoarterial difference was not significant. The data obtained by transabdominal cord sampling from relatively undisturbed fetuses were in agreement with the data obtained at cesarean section; this information suggests that these differences between small for gestational age and appropriate for gestational age infants reflected steady-state conditions.

Venous drainage of the human uterus: respiratory gas studies in normal and fetal growth-retarded pregnancies.

OBJECTIVE: To determine respiratory gas relationships between the uterine veins and umbilical vein in normal and pregnancies complicated by intrauterine growth retardation. STUDY DESIGN: Respiratory gases were measured in both uterine veins and the umbilical vein in eight normal and 13 pregnancies with intrauterine growth retardation. RESULTS: No significant differences were found in the placental versus nonplacental uterine veins. There was a significant correlation for umbilical and uterine venous values of PO2 (p less than 0.002) and PCO2 (p less than 0.004) in appropriate-for-gestational-age pregnancies, umbilical venous PO2 was always less than uterine venous PO2, and PCO2 always greater than uterine. The transplacental gradient was significantly higher in intrauterine growth retarded than appropriate-for-gestational-age pregnancies for both POC2 and PCO2. There was a lower uterine oxygen extraction in intrauterine growth retarded pregnancies (p less than 0.05). CONCLUSION: There is no consistent relationship between placental venous drainage in each uterine vein and placental location. The human placenta simulates a relatively inefficient venous equilibrator and the larger transplacental gradients in intrauterine growth retarded pregnancies may reflect differences in both perfusion pattern and placental structure.

Diagnostic value of blood sampling in fetuses with growth retardation.

BACKGROUND: Fetuses with intrauterine growth retardation are delivered if they have evidence of distress, as manifested by abnormalities in the fetal heart rate and umbilical-artery blood flow. We studied whether umbilical-blood sampling might provide further information useful for management. METHODS: We measured hemoglobin and lactate concentrations, oxygen content, pH, blood gas levels, and base deficit in umbilical-vein blood and correlated these measurements with the heart rate and umbilical-artery wave forms recorded by Doppler velocimetry in 56 fetuses with growth retardation. Twenty-one fetuses had normal heart rates and normal results of velocimetry, 24 had normal heart rates and abnormal results of velocimetry (indicative of decreased diastolic flow), and 11 had abnormal heart rates and abnormal results of velocimetry. RESULTS: None of the 21 fetuses with normal heart rates and velocimetry had hypoxia or acidemia. Of the 24 fetuses with normal heart rates and abnormal velocimetry, 4 (17 percent) had moderate lactic acidosis, 1 (4 percent) had a low pH value, and 3 (12 percent) had hypoxia. Of the 11 fetuses with abnormal heart rates and velocimetry, 7 (64 percent) had lactic acidosis, low blood oxygen content, and low pH values. The absence of end-diastolic flow increased the risk of hypoxia and acidemia. The proportion of fetuses with elevated hemoglobin concentrations was similar among the three groups. CONCLUSIONS: Assessment of fetal oxygenation and acid-base balance is not indicated in fetuses with growth retardation if their heart rates and the results of velocimetry are normal. If the results of velocimetry are abnormal, fetal-blood sampling can distinguish fetuses that have growth retardation alone from those that also have hypoxia and acidosis, and thus may aid in determining the optimal time of delivery.

Umbilical amino acid concentrations in normal and growth-retarded fetuses sampled in utero by cordocentesis.

Fetal plasma amino acid concentrations were obtained by cordocentesis at midgestation in 11 normal (appropriate for gestational age) fetuses and at late gestation in 12 small-for-gestational-age fetuses, and at cesarean section in 14 normal term infants. In normal fetuses total molar amino acid concentrations and fetal/maternal total molar concentration ratios did not change significantly between the second and third trimesters. Fetal and maternal concentrations of most amino acids were significantly correlated at both midgestation and late gestation. Small-for-gestational-age fetuses had significantly lower concentrations of total alpha-aminonitrogen; this was mainly because of a reduction of the branched chain amino acids valine, leucine, and isoleucine, and of lysine and serine. Maternal arterial concentrations of phenylalanine, arginine, histidine, and alanine were elevated in small-for-gestational-age pregnancies. Thus there are only minor changes in amino acid concentrations between midgestation and late gestation in normal fetuses with a constant fetal/maternal ratio. In small-for-gestational-age infants a significant reduction in alpha-aminonitrogen and in most essential amino acids was demonstrable in utero weeks before delivery.

Cord sampling for the evaluation of oxygenation and acid-base balance in growth-retarded human fetuses.

In 14 pregnancies complicated by intrauterine growth retardation, the umbilical cord was sampled before delivery under ultrasonic guidance for rapid fetal karyotyping. Fetal blood was analyzed for respiratory gases, acid-base balance, and lactate concentrations. Two patients were excluded from the study because cord samples were diluted with amniotic fluid. In six patients (group 1), the clinical assessment warranted continuation of pregnancy. Cesarean sections were performed in the remaining eight patients (group 2) within 8 hours of cord sampling. The data from the two groups were compared with those obtained from umbilical venous blood at the time of elective repeat cesarean section in term appropriate for gestational age infants (controls). No significant difference in PO2 was found between groups 1 and 2 and controls. In contrast, there were significant differences in oxygen saturation and acid-base balance between groups 1 and 2. Lactate concentration was inversely correlated with pH and was elevated in five of six fetuses requiring a prompt cesarean section: In two of these five fetuses, nonstress fetal heart rate tracings were reactive. The results suggest that fetal blood biochemistry, and particularly lactate concentration, may represent an additional indicator of fetal well-being in pregnancies complicated by intrauterine growth retardation.

Respiratory gases, acid-base balance and lactate concentrations of the midterm human fetus.

Respiratory gases, acid-base balance, and lactate and hemoglobin concentrations were measured in 14 fetal blood samples between 17 and 21 weeks of gestation. The samples were obtained at the time of fetoscopy performed for prenatal diagnosis. Results have been compared with two reference groups: (a) 4 patients in whom fetal cord blood sampling was performed at 32-36 weeks of gestation, and (b) 10 patients at the time of elective cesarean section, 35-39 weeks. PO2 and oxygen saturations were significantly higher and hemoglobin concentration lower in the mid-gestation fetus. Acid-base balance was not significantly different. There was a significant correlation between maternal and fetal hemoglobin concentrations. The oxygen affinity of fetal blood was not significantly different from that described for term fetuses with a oxygen saturation of less than 90%.