Noninvasive determination of fetal rh blood group, D antigen status by cell-free DNA analysis in maternal plasma: experience in a Brazilian population.

We evaluated the diagnostic accuracy of Rh blood group, D antigen (RHD) fetal genotyping, using real-time polymerase chain reaction in maternal blood samples, in a racially mixed population. We performed a prospective study conducted between January 2006 and December 2007, analyzing fetal RHD genotype in the plasma of 102 D- pregnant women by real-time polymerase chain reaction, targeting exons 7 and 10 of the RHD gene. Genotype results were compared with cord blood phenotype obtained after delivery or before the first intrauterine transfusion when necessary.

Rh alloimmunization: Doppler or amniotic fluid analysis in the prediction of fetal anemia?

Objective: Compare the results of amniocentesis and those of middle cerebral artery peak systolic velocity to detect anemic fetuses in Rh alloimmunized pregnancies.

Method: Descriptive observational study involving 99 consecutive Rh-negative pregnancies: 74 alloimmunized patients submitted to amniotic fluid spectrophotometry (group 1) and 25 alloimmunized cases managed with Doppler ultrasonography (group 2). Variables analyzed were the following: need for neonatal transfusion and neonatal hematocrit.

Perinatal mortality in Rh alloimmunized patients.

Objective: Evaluate and compare the perinatal mortality of Rh-negative pregnancies managed at São Paulo Federal University during a 9-year period, using either amniocentesis or middle cerebral artery peak systolic velocity.

Method: Descriptive observational study involving 291 consecutive Rh-negative pregnancies managed between January 1995 and January 2004. The perinatal mortality of 99 alloimmunized patients was compared with 192 Rh-negative unimmunized patients (control group).