Diagnostic accuracy of noninvasive polymerase chain reaction testing for the determination of fetal rhesus C, c and E status in early pregnancy.

OBJECTIVE: The aim of the study was to determine the sensitivity, specificity and accuracy of noninvasive tests for the fetal rhesus CcEc (RHCE) alleles C, c and E in early pregnancy. DESIGN: A prospective clinical trial was carried out to evaluate diagnostic accuracy. SETTING: Women were recruited at four centres specialising in prenatal diagnosis. Peripheral blood and amniotic fluid samples were obtained and sent to a single laboratory for analysis. SAMPLE: A total of 233 tests (46 for C, 87 for c and 100 for E) were performed on 181 specimens obtained from pregnant women at weeks 12 to 28 (median week 16) of gestation. METHODS: Following automated extraction of fetal DNA from maternal plasma, two different real-time polymerase chain reaction (PCR) protocols were used for the detection of the C, c and E alleles of RHCE. The results of the PCR were compared with genotyping results for the amniotic fluid. MAIN OUTCOME MEASURES: Failure rate, sensitivity, specificity and accuracy were the main outcome measures. RESULTS: Unequivocal results were obtained for all specimens. With the first PCR protocol, the sensitivity was 100% for C, 38% for c and 59% for E. In contrast, with the second protocol, the sensitivity for C, c and E was 100%. The specificity for all assays was found to be between 99% and 100%. CONCLUSIONS: A highly accurate protocol has been identified for the detection of fetal RHCE alleles in maternal plasma in early pregnancy. This noninvasive approach can be considered as a useful test in the management of pregnancies with anti-c, anti-E or anti-C alloimmunisation.

Fetal bone metabolism in normal and rhesus isoimmunised pregnancies.

OBJECTIVE: To construct gestation-specific reference intervals for fetal concentrations of biochemical markers of bone metabolism and assess the effect of rhesus isoimmunisation on these. METHODS: Fetal blood samples were obtained by cordocentesis from 175 pregnancies (43 complicated by rhesus isoimmunisation) and assayed for carboxy terminal pro-peptide of type I pro-collagen (PICP) and cross-linked carboxyterminal telopeptide of type I collagen (ICTP) which directly monitor the rate of bone formation and resorption respectively. RESULTS: Both plasma PICP and ICTP were negatively correlated with gestational age (r = -0.351 and -0.472 for PICP and ICTP, respectively, and P < 0.001 for both). In fetuses affected by rhesus isoimmunisation PICP levels were lower (P=0.030) and more variable (P <0.001) than expected, compared with normal unaffected fetuses. However, no such differences were found in the ICTP levels. In the fetuses affected by rhesus isoimmunisation there was a significant correlation between haemoglobin concentration and both PICP (r = 0.504, P = 0.001) and ICTP (r = 0.343, P = 0.030). CONCLUSIONS: Fetal bone turnover declines from early second trimester to term, and may be deranged in fetuses affected by rhesus isoimmunisation.

Posibilidad de utilización de los precursores hemopoyéticos durante el período prenatal / Possibilities for using hematopietic precursor in the prenatal period

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Fetal pancreatic function in infants of diabetic and rhesus-isoimmunized women.

OBJECTIVE: To measure insulin and glucagon concentrations in amniotic fluid (AF) collected near term in basal conditions and after an arginine test in diabetic, rhesus-isoimmunized, and control pregnant women. METHODS: At baseline, AF was collected from 44 diabetic, 32 rhesus-isoimmunized, and 27 control pregnant women in late pregnancy. Fifty-two diabetic, six rhesus-isoimmunized, and nine control pregnant women had amniocentesis 2 hours after arginine infusion (30 g intravenous/30 minutes) at 33-36 weeks. RESULTS: Baseline AF glucose concentrations were significantly greater in diabetic women than the other conditions, and they related to the gestational age in the women with hemolytic disease of the newborn. Insulin and glucagon AF content of isoimmunized pregnancies overlapped controls, whereas insulin and insulin/glucagon molar ratios were significantly higher, and glucagon values lower, in diabetic pregnancies compared with isoimmunized and control pregnancies. In isoimmunized pregnancies, the AF concentrations of glucose, insulin, and glucagon were correlated with gestational age (less than 34, 34 weeks or more). The samples collected after arginine infusion, compared with those collected at baseline, showed significantly greater insulin and insulin/glucagon molar ratio values in diabetic (28 +/- 5 versus 11 +/- 1 microU/mL, P = .001; 29.4 +/- 1.7 versus 12.0 +/- 2.8, P = .001) and in Rh pregnant women (18 +/- 6 versus 7.7 +/- 0.7 microU/mL, P = .001; 30 +/- 9 versus 3.4 +/- 0.4 I/G, P = .001), whereas no significant difference was observed in the controls. CONCLUSION: Basal islet hormone concentrations in AF are modified by maternal diabetes and further influenced by arginine administration. Arginine produces an AF response that is similar in pregnancies complicated by diabetes mellitus and rhesus-isoimmunization, despite different (hyperglycemia and euglycemia) maternal blood glucose levels.

[Prevention of fetal hemolytic disease: it is time to take action]. / Prévention de la maladie hémolytique du foetus et du nouveau-né: il faut agir!

In spite of the progress made since 1970 in specific prevention by anti-rhesus immunoglobulins, and improved management of at-risk pregnancies, allo-immunization due to the erythrocytic Rh 1 antigen (formerly known as Rhesus D or Rh D) remains widespread. In fact, anti-Rh 1 antibodies currently constitute over one-third of the immune antibodies detected after pregnancy. The prevention of allo-immunization against the Rh 1 antigen is therefore still problematical, and concerns approximately one pregnant woman in seven. The etiology and pathology of fetal hemolytic disease have been recalled, and the treatment approach during pregnancy and delivery has been carefully examined. Tests for quantifying the risk of fetomaternal hemorrhage have also been described. This approach aims at improving the methods of preventing allo-immunization (e.g., during pregnancy and delivery) and the efficacy of treatment. It is also stated that if the necessary preventive action is not taken in cases of allo-immunization due to to the Rh 1 antigen, this should be considered a grave medical fault.

Frecuencia de antígenos eritrocitarios del sistema Rh-Hr en los cónyuges de mujeres Rh negativo / Antigenic profile of Rh-Hr erythrocytes system in the couple of the Rh negative women

Con el objetivo de establecer el perfil antigénico del sistema eritrocitario Rh-Hr, se estudiaron a 177 cónyugues de mujeres Rh negativo. En 15 casos (8.5 por ciento), fueron Rh negativo y 162 casos (91.5 por ciento) fueron Rh positivo. Con respecto a la cigocidad probable al antígeno D, en 100 casos (56.5 por ciento) son homocigotos , en 62 casos (35 por ciento), son hetoocigostos y 15 cónyuges (8.5 por ciento) Rh negativo. El fenotipo probable, de acuerdo a la frecuencia porcentual de casos, fueron DCCee (R1/r) en 48 cónyuges (27.1 por ciento), DCCee (R1/R1), con 46 casos (26 por ciento), DCcEe (R1/R2) en 36 casos (20.3 por ciento), DccEe (R2/r) con 14 casos (7.9 por ciento), DccEE (R2/R2) en 13 casos (7.3 por ciento), DCCEe (R1/RZ) y Dccee (Ro/r) con 2 casos cada uno (1.1 por ciento) y DCcEE (R2/RZ) con un sólo caso (0.5 por ciento). En los cónyuges Rh negativo, la más frecuente con 14 casos (7.9 por ciento) fue el fenotipo dcce (r/r y con el fenotipo dccEe (r"/r), se encontró sólo un caso (0.56 por ciento). La frecuencia génica de la población r/r (Rh negativo), mostró diferencia significativa (p < 0.025) con respecto a la frecuencia esperada de los sujetos Rh negativos en la población del Valle de México.