Noninvasive fetal RHD genotyping from maternal plasma in an admixed Brazilian population.

We evaluated the efficacy of noninvasive fetal Rhesus D (RHD) genotyping from maternal plasma in a highly admixed population. Fifty-five blood samples from RhD-negative pregnant women from Brazil were processed for extraction of cell-free plasma DNA. Real-time PCR was performed to amplify segments of exons 5 and 7 from the RHD gene, as well as for detection of the SRY gene to confirm the presence of fetal DNA. Fetal genotyping results were compared with the RhD phenotype determined from newborn cord blood samples obtained at birth. Thirty-two samples were RHD-positive, 18 were RHD-negative and 5 were inconclusive due to amplification of only one RHD exon. In 43 samples, the fetal RHD genotype was compared to the neonatal RhD phenotype, and only one result was discordant, due to false-negative serology. There was one false SRY genotyping negative result. We conclude that noninvasive fetal RHD genotyping from maternal blood provides accurate results and suggests its viability as a clinical tool for the management of RhD-negative pregnant women in an admixed population.

Cryopreservation does not alter karyotype, multipotency, or NANOG/SOX2 gene expression of amniotic fluid mesenchymal stem cells.

Cryopreservation of mesenchymal stem cells from amniotic fluid is of clinical importance, as these cells can be harvested during the prenatal period and stored for use in treatments. We examined the behavior of mesenchymal stem cells from human amniotic fluid in culture that had been subjected to cryopreservation. We assessed chromosomal stability through karyotype analysis, determined whether multipotent capacity (differentiation into adipogenic, chondrogenic, and osteogenic cells) is maintained, and analyzed SOX2 and NANOG expression after thawing. Five amniotic fluid samples were cryopreserved for 150 days. No chromosomal aberrations were observed. The expression levels of NANOG and SOX2 also were quite similar before and after cryopreservation. Capacity for differentiation into adipogenic, chondrogenic, and osteogenic tissues also remained the same. We conclude that cryopreservation of amniotic fluid does not alter karyotype, NANOG/SOX2 gene expression, or multipotent capacity of stem cells that have been collected from amniotic fluid during pregnancy.

Influence of fetal anemia on fetal splenic artery Doppler in Rh-alloimmunized pregnancies.

OBJECTIVE: To verify the correlation between fetal splenic artery Doppler velocimetry and fetal hemoglobin (Hb) levels in Rh alloimmunization. METHODS: Splenic artery Doppler peak systolic velocity (PSV) and pulsatility index (PI) were obtained before cordocentesis in rhesus-alloimmunized fetuses. Doppler was performed before 80 cordocentesis in 36 patients between 20 and 35 weeks of gestation. Mild, moderate and severe anemia were defined as a Hb deficit of >or=2, >or=5 and >or=7 g/dl respectively. RESULTS: Anemia was noted in 64% of the fetuses and moderate and severe anemia in 18 and 21%. Splenic artery PSV was higher in groups with moderate (p = 0.001) and severe (p < 0.000) anemia but not in the group with mild anemia (p = 0.189) when compared to non-anemic fetuses. Splenic artery PI was higher only in the severely anemic group (p = 0.001). CONCLUSIONS: The splenic artery PI and PSV are higher in fetuses with severe anemia.

Cardiofemoral index as an ultrasound marker of fetal anemia in isoimmunized pregnancy.

OBJECTIVE: To test a new noninvasive ultrasound method for diagnosing fetal anemia in red blood cell isoimmunized pregnancies. METHODS: A diagnostic accuracy study was carried out to determine the cutoff point of an ultrasound measurement, the cardiofemoral index (CFI), calculated using the biventricular outer dimension (BVOD) and femur length to diagnosis severe anemia. The CFI measurement was performed before each of the 336 cordocenteses on 131 fetuses. Diagnosis test analysis and receiver-operating characteristics (ROC) curves were used and the area under the curve (AUC) was calculated to compare the overall accuracy of the CFI for anemia diagnosis, between fetuses with or without previous intrauterine transfusions (IUT). RESULTS: At first cordocentesis (n=131) the AUC was 0.75 (95% CI, 0.66-0.84). For cases where fetuses had undergone 1 previous transfusion (n=88) the AUC was 0.76 (95% CI, 0.64-0.88) and at the time of the third cordocentesis for IUT (n=53) it was 0.73 (95% CI, 0.59-0.86). For a 0.59 CFI threshold to diagnosis fetuses with hemoglobin deficit above 5 g/dL, sensitivity values were 87.2%, 88.0%, and 94.1% respectively for fetuses without IUT, with 1 IUT, and with 2 IUTs. Likelihood ratios for positive (LR+) and negative (LR-) test results were 1.98, 2.05, 1.69 and 0.23, 0.21, 0.13 respectively. CONCLUSION: The cardiofemoral index may be an effective noninvasive marker of severe fetal anemia in high-risk fetuses, with accuracy similar for fetuses either with or without previous transfusions.