Patrizia Bozzetti

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.

Venous drainage of the human uterus: Respiratory gas studiesin 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.

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.

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.

Comparison of Fetal and Neonatal Growth Curves in Detecting Growth Restriction

OBJECTIVE: To evaluate the outcome of intrauterine growth restriction (IUGR) infants with abnormal pulsatility index of the umbilical artery according to the neonatal birth weight/gestational age standards and the intrauterine growth charts. METHODS: We analyzed 53 pregnancies with severe IUGR classified as group 2 (22 IUGR: abnormal pulsatility index and normal fetal heart rate) and group 3 (31 IUGR: abnormal pulsatility index and fetal heart rate). Neonatal birth weight/gestational age distribution, body size measurements, maternal characteristics and obstetric outcome, and neonatal major and minor morbidity and mortality were compared with those obtained in 79 singleton pregnancies with normal fetal growth and pulsatility index, matched for gestational age (appropriate for gestational age [AGA] group). Differences were analyzed with the &khgr;2 test and the Student t test. Differences between means corrected for gestational age in the different groups were assessed by analysis of covariance test. A P<.05 was considered significant. RESULTS: At delivery, using the neonatal standards, 25 of 53 (47%) IUGR showed a birth weight above the 10th percentile (IUGRAGA), whereas in 28, birth weight was below the 10th percentile (IUGR small for gestational age [SGA]—IUGRSGA). All body size measurements were significantly higher in AGA than in IUGRAGA and IUGRSGA. Forty-nine of 79 (62%) AGA and 49 of 53 (92%) IUGR were admitted to the neonatal intensive care unit (P<.001). One of 79 (1%) AGA and 6 of 53 (11%) IUGR newborns died within 28 days (P<.02). Major and minor morbidity was not different. CONCLUSION: This study shows that neonatal outcome is similar in IUGR of the same clinical severity, whether or not they could be defined AGA or SGA according to the neonatal standards. Neonatal curves are misleading in detecting low birth weight infants and should be used only when obstetric data are unavailable. LEVEL OF EVIDENCE: II

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%.

Neonatal Morbidity and Mortality in Intrauterine Growth Restricted (IUGR) Pregnancies Is Predicated Upon Prenatal Diagnosis of Clinical Severity

The objective of this work was to determine whether the prenatal determinates of clinical severity in intrauterine growth restricted pregnancies, established by abdominal circumference measures, correlates with neonatal morbidity and mortality. A total of 336 singleton pregnancies with intrauterine growth restriction were subdivided into group 1 (normal fetal heart rate and pulsatility index of the umbilical artery: 251 cases), group 2 (normal fetal heart rate and abnormal pulsatility index: 50 cases), and group 3 (abnormal fetal heart rate and pulsatility index: 35 cases). Gestational age, birth weight, body mass index, placental weight, and Apgar score were significantly related to the severity of intrauterine growth restriction (P < .001). Neonatal survival was 100%, 96%, and 57% in the 3 groups, respectively (P < .001). Greater than 80% of neonates of group 1 had no complications when compared to group 2 (54%) and group 3 (10%); P < .001. Gestational age was the only independent variable significantly associated with neonatal outcomes. The data confirm that the classification of clinical severity of intrauterine growth restriction based on biophysical parameters is clinically relevant to predict neonatal outcome.

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.