Umberto Nicolini

Erythropoietic suppression in fetal anemia because of Kell alloimmunization.

OBJECTIVE Our purpose was to test the hypothesis that maternal anti-Kell alloimmunization produces fetal anemia by erythroid suppression. STUDY DESIGN Erythropoiesis in 11 anemic fetuses from maternal anti-Kell alloimmunization was compared with that in 11 fetuses where the mother was alloimmunized to RhD; each was matched for hematocrit, gestational age, hydrops, and perinatal outcome. Comparisons of the difference were performed by either paired t or Wilcoxon tests. RESULTS The anti-Kell group had reduced reticulocytosis (p = 0.007) and erythroblastosis (p = 0.045) and lower amniotic fluid bilirubin concentrations (p = 0.02) in comparison with the anti-D group. No correlation was found between hematocrit and reticulocytosis in the anti-Kell group, whereas the anti-D group had a significant linear relationship (r = 0.63, p < 0.05), indicating a progressive reticulocytosis in response to the degree of anemia. CONCLUSION These findings suggest that erythroid suppression, rather than hemolysis, is the predominant mechanism in producing fetal anemia related to maternal Kell alloimmunization. Fetal blood sampling is the investigation of choice in the evaluation of anemia related to maternal Kell alloimmunization, because reduced hemolysis means amniotic fluid bilirubin concentrations correlate poorly with anemia.

Fetal urine biochemistry: an index of renal maturation and dysfunction

Objective To construct a reference range for fetal urinary sodium, potassium, urea, creatinine, calcium and phosphate with gestation and to assess to what extent these biochemical indices are modified in fetuses with lower urinary tract obstruction.

Fetal and neonatal echocardiographic findings in twin-twin transfusion syndrome

OBJECTIVE The studys aim was to analyze the type of cardiac involvement in fetuses or infants with twin-twin transfusion syndrome. STUDY DESIGN Seventeen pairs of monochorionic diamniotic twin fetuses with twin-twin transfusion syndrome underwent serial Doppler echocardiographic studies. Repeated decompressive amniocenteses were performed in all pregnancies. RESULTS No specific cardiac involvement was seen in donor twins in utero or after birth. All recipient twin fetuses showed variable degrees of biventricular hypertrophy and dilation with tricuspid regurgitation. These features were also evident in 45% of the recipient twin neonates. The fluid unbalance resolved with serial amniocenteses in 9 cases and in a further 2 after the death of the donor twin; in all 11 of these recipient twin fetuses there was some degree of improvement of the cardiac involvement, which became normal in all surviving recipient twin infants within 40 days to 6 months after birth. CONCLUSION Features of cardiac hypertrophy with signs of a prehydropic or hydropic state develop during fetal life in recipient twins in twin-twin transfusion syndrome; this impairment is reversible with the resolution of the fluid imbalance or after delivery.

Fetofetal transfusion syndrome: do the neonatal criteria apply in utero?

Thirteen fetuses (five twin, one triplet) were compromised by fetofetal transfusion syndrome in six pregnancies, five in the mid trimester, and one in the third trimester. This diagnosis, which was suspected because of ultrasound findings of discordant growth, discordant amniotic fluid volumes, concordant external genitalia, and monochorial placentation, was confirmed postnatally in each. Nine fetuses underwent blood sampling to aid diagnosis and assessment of fetal wellbeing. In contrast to fetofetal transfusion syndrome investigated postnatally, a difference in haemoglobin concentration of 50 g/l or more in utero was found in only one pregnancy, which was near term, although all had fetal erythroblastaemia and a difference in weight of 20% or more. In vivo confirmation of shared circulation was achieved in two pregnancies by transfusing adult Rh negative red cells into the smaller fetus and then detecting them by Kleihauer testing in blood aspirated from the larger. Invasive procedures also yielded information on fetal blood gas measurements (acidaemia in four and hypoxaemia in six) and amniotic pressure (raised in two). We suggest that comparison of haemoglobin concentrations is inaccurate in fetofetal transfusion syndrome in utero, the diagnosis of which may necessitate detection of a shared circulation using a marker such as adult red cells.

Fetal urine analysis for the assessment of renal function in obstructive uropathy

OBJECTIVES The assessment of fetal renal function plays a key role in the evaluation of posterior urethral valve obstruction cases. The aim of our study was to determine the value of several urinary compounds, including beta 2-microglobulin, N-acetyl-beta-D-glucosaminidase, and microalbumin in the assessment of prenatal renal function in cases of posterior urethral valve and their potential role in the selection of such cases for in utero shunting. STUDY DESIGN A range of urinary compounds was measured, including beta 2-microglobulin, N-acetyl-beta-D-glucosaminidase, and microalbumin in 25 cases of posterior urethral valve obstruction. These cases were divided into four groups based on outcome. The Mann-Whitney test and analysis of covariance were used. RESULTS Sodium, calcium, and beta 2-microglobulin were the best predictors for fetal survival. beta 2-Microglobulin values > 13 mg/L were almost invariably associated with fatal outcome. CONCLUSION The estimation of beta 2-microglobulin may help in counseling parents and in selecting cases for in utero shunting.

Limited role of fetal blood sampling in prediction of outcome in intrauterine growth retardation

Fetal acid-base status was evaluated on 66 blood samples taken for rapid karyotyping from 58 growth-retarded fetuses. Before blood sampling, doppler blood flow studies of the umbilical artery showed end-diastolic frequencies to be absent in 32 fetuses (group 1) and present in 26 (group 2). Fetuses with chromosomal (n = 4) or structural (n = 8) abnormalities were excluded from subsequent analysis. Gestational age at blood sampling (27.8 [95% CI 26.5-29.1] vs 32.2 [30.4-34.1] weeks) and time from sampling to delivery (median 2 (range 0-35] vs 14 [0-77] days) were significantly lower in group 1 than group 2. There were no perinatal deaths in group 2 whereas mortality in group 1 was 65.4%. There were significant differences between the groups at blood sampling in pH, pO2, pCO2, base equivalents, and nucleated-red-cell count, but within group 1 these measurements were similar in surviving fetuses and those who died perinatally. Since acid-base determination does not predict perinatal outcome in growth-retarded fetuses, fetal blood sampling has a limited role in monitoring fetal wellbeing.

Fetal blood sampling immediately before and within 24 hours of death in monochorionic twin pregnancies complicated by single intrauterine death

OBJECTIVE Our goal was to investigate the mechanisms that play a role in intrauterine death in monochorionic twins and that contribute to the high perinatal mortality and morbidity in the survivors. STUDY DESIGN In 8 monochorionic twin pregnancies complicated by the intrauterine death of a single twin, we took samples from 5 twin fetuses immediately before death and from 4 of their cotwins and also from 4 surviving fetuses within 24 hours after death of the cotwin. RESULTS Four of the 5 fetuses sampled who subsequently died were acidemic and 3 were hypoxemic. None of these fetuses or their cotwins were anemic at that time. All 4 survivors sampled within 24 hours of the death of each cotwin had low hematocrits. CONCLUSION Fetal anemia, probably the consequence of acute blood loss just before the time of death of the cotwin, may play a role in the high mortality and morbidity found in the surviving twin. It is unlikely that immediate delivery of the surviving twin after death could affect the outcome.

Consequences of fetomaternal haemorrhage after intrauterine transfusion.

Fetomaternal haemorrhage was studied after 68 consecutive fetal intravascular transfusions performed in 20 patients with Rh isoimmunisation. alpha Fetoprotein concentration was assayed in maternal blood taken before, and immediately after each transfusion and three and 24 hours later. An increase of 50% or more in the concentration in any of the samples after transfusion was considered to indicate fetomaternal haemorrhage. Fetal alpha fetoprotein concentration in blood sampled before transfusion was also assayed and the amount of fetomaternal haemorrhage calculated. Fetomaternal haemorrhage occurred in 21 of 32 patients with an anterior placenta and in six of 36 with a posterior or fundal placenta. The mean estimated volume of haemorrhage was 2.4 ml, which was on average equal to 3.1% of the total fetoplacental blood volume. When the volume of fetomaternal haemorrhage at the first transfusion was greater than 1 ml there was a greater increase in maternal Rh (D) antibody titres and a greater fall in fetal packed cell volume. Sampling of fetal blood should not be routinely done early in patients with Rh isoimmunisation, and intrauterine transfusion should be delayed as long as possible. Sampling sites other than the placental cord insertion reduces the risk of fetomaternal haemorrhage.

Low Amniotic Pressure in Oligohydramnios - Is This the Cause of Pulmonary Hypoplasia

The mechanism by which oligohydramnios produces lung hypoplasia is not understood. The current theory that extrinsic compression of the fetal thorax causes hypoplasia, either by inhibiting breathing movements or by squeezing out lung liquid, is not supported by observational or experimental data, or by our finding of decreased amniotic pressure around the fetus in oligohydramnios. We hypothesize that lung hypoplasia results from excess loss of lung liquid because of a reduction in amniotic pressure, and hence an increase in the alveolar-amniotic pressure gradient. The magnitude of this increased pressure gradient is calculated to exceed the small standing tracheal pressure; thus low amniotic pressure overcomes the normal laryngeal retentive mechanisms and allows a larger quantity of lung liquid to escape. In the prevention of pulmonary hypoplasia, a role is suggested for the instillation of artificial amniotic fluid to restore normal amniotic pressure.

Two‐dimensional vs. two‐ plus four‐dimensional ultrasound in pregnancy and the effect on maternal emotional status: a randomized study

To assess whether the addition of four‐dimensional (4D) ultrasound to a conventional two‐dimensional (2D) scan in the second/third trimester of pregnancy facilitates maternal recognition of specific fetal structures and movements and causes an emotional impact, as subjectively perceived by the woman.