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PubMed2004

Prospective study of parental choice for aneuploidy screening in assisted conception versus spontaneously conceived twins.

The aim of this study was to evaluate and compare parental choice towards the use of aneuploidy screening and diagnostic techniques after assisted conception versus spontaneously conceived pregnancy. A total of 193 patients with consecutive twin pregnancies participated in the study, including 143 who spontaneously conceived and 50 who conceived following assisted reproduction treatment. Patients were investigated prospectively for their choice in the prenatal screening/diagnosis of aneuploidy. In the group of patients who conceived spontaneously, 111 (77.6%) opted initially for the non-invasive screening based on nuchal translucency measurements, whereas in the assisted conception group, 44 (88%) opted for the non-invasive screening. In the spontaneous conception group, 32 (22.4%) presented because they had a positive serum screening test or because they had opted for a chorionic villus sampling (CVS) or an amniocentesis for advanced maternal age. In the assisted conception group only six patients (12%) opted for amniocentesis. The difference in choice of noninvasive versus invasive screening between those with spontaneous and those with assisted conception was not significant, but those who had conceived spontaneously after the age of 37 years were significantly more likely (P < 0.05) to request an invasive diagnostic procedure through all maternal age groups. When needed, an amniocentesis was preferred to CVS. These data also indicate that the antenatal counselling needs to be adapted to couples presenting with an assisted conception twin pregnancy.

Adult↗
PubMed1998

Prenatal diagnosis of the fetal Rhc genotype from peripheral maternal blood.

OBJECTIVE: To determine the fetal Rhc genotype by using the polymerase chain reaction (PCR) amplification procedure and maternal blood at the different steps of the fetal cell enrichment process. METHODS: Maternal peripheral venous blood samples were obtained from 11 pregnant women homozygous for the C antigen before amniocentesis. Three were not alloimmunized and eight were alloimmunized. The fathers were known to be heterozygous or homozygous for the c antigen by serologic testing. The mononuclear cell layer was isolated from maternal blood and flow sorted using monoclonal antibodies to CD36 or CD71 and glycophorin A. This was followed by PCR of the blood, mononuclear cells, and the sorted cells with allele-specific primers to RhCc genes. Gel electrophoresis was performed to predict fetal Rhc genotype. The fetal RhCc genotype was confirmed by serologic and DNA testing. RESULTS: All infants were positive for the Rhc gene. The positive fetal Rhc genotype was determined correctly in three of the 11 maternal blood samples without enrichment, in six of the nine mononuclear cell samples, and in seven of the eight sorted cell samples. The fetal genotype from one sorted sample was predicted to be homozygous C. One infant was determined by serology on cord blood to be negative for the c antigen, but repeated infant DNA amplification was consistent with the c genotype. CONCLUSION: Noninvasive fetal Rhc genotyping can be determined by PCR amplification of the rare fetal cells in maternal blood. These data reaffirm that enrichment of maternal blood for fetal cells is necessary to improve the sensitivity of the test.

Blood Grouping and Crossmatching↗
PubMed2004

Feasibility study for a microchip-based approach for noninvasive prenatal diagnosis of genetic diseases.

Fetal DNA in maternal plasma may represent a source of genetic material for prenatal noninvasive diagnosis of genetic diseases. We evaluated a cohort of physiological pregnancies to determine if fetal DNA can be retrieved at any gestational week in sufficient quantity to be analyzed with advanced mutation detection technologies. We performed fetal DNA quantification by real-time polymerase chain reaction (PCR) on the SRY gene in 356 women sampled from 6 to 40 gestational weeks. Fetal DNA was retrieved at any week. All female fetuses were correctly identified. In 5 of 188 (2.6%) male-bearing pregnancies, no amplification was obtained. For noninvasive testing, complete clearance of fetal DNA after delivery is mandatory. Long-term persistence was not detected in women with previous sons or abortions. These findings confirm that maternal plasma may represent the optimal source of fetal genetic material. For noninvasive diagnosis of genetic diseases, we evaluated microchip technology. The detection limit for a minority allele determined by diluting a mutated DNA into a wild-type plasma sample was 5 genome equivalents, indicating that the test might be applied to the identification of paternally inherited fetal alleles in maternal plasma. The addition of peptide nucleic acids (PNAs) to either the PCR reaction or the chip hybridization mixture allowed approximately 50% inhibition of wild-type allele signals.

Adult↗
PubMed1998

Prenatal diagnosis of fetal RhD status by molecular analysis of maternal plasma.

BACKGROUND: The ability to determine fetal RhD Status noninvasively is useful in the treatment of RhD-sensitized pregnant women whose partners are heterozygous for the RhD gene. The recent demonstration of fetal DNA in maternal plasma raises the possibility that fetal RhD genotyping may be possible with the use of maternal plasma. METHODS: We studied 57 RhD-negative pregnant women and their singleton fetuses. DNA extracted from maternal plasma was analyzed for the RhD gene with a fluorescence-based polymerase-chain-reaction (PCR) test sensitive enough to detect the RhD gene in a single cell. Fetal RhD status was determined directly by serologic analysis of cord blood or PCR analysis of amniotic fluid. RESULTS: Among the 57 RhD-negative women, 12 were in their first trimester of pregnancy, 30 were in their second trimester, and 15 were in their third trimester. Thirty-nine fetuses were RhD-positive, and 18 were RhD-negative. In the samples obtained from women in their second or third trimester of pregnancy, the results of RhD PCR analysis of maternal plasma DNA were completely concordant with the results of serologic analysis. Among the maternal plasma samples collected in the first trimester, 2 contained no RhD DNA, but the fetuses were RhD-positive; the results in the other 10 samples were concordant (7 were RhD-positive, and 3 RhD-negative). CONCLUSIONS: Noninvasive fetal RhD genotyping can be performed rapidly and reliably with the use of maternal plasma beginning in the second trimester of pregnancy.

Blood Grouping and Crossmatching↗
PubMed1982

Fetal respiratory movements: relationship to postnatal respiratory capacity.

Sixty-six normal and 346 pathologic pregnancies have been investigated by means of dynamic ultrasound for determination of fetal intrauterine respiratory amplitudes in over 930 scans of 30-minute duration. Ten fetuses developed respiratory distress syndrome (RDS), and all of these showed antenatally either falling (more than 2 SD) or abnormally low thoracic and abdominal amplitudes. No fetuses with amplitude measurements within the normal range (mean +/- 2 SD) developed RDS (p less than 0.001, X2 test). In 74 women, measurement of amniotic lecithin was performed within one half hour before a dynamic ultrasound registration, predictive value, or specificity between these two methods in identifying RDS. The conclusion is that the pathogenesis of RDS may be both biochemical and biophysical, and that this new noninvasive method may easily be used as a screening test for postnatal respiratory capacity in high-risk pregnancies, since only 10 equal and regular respiratory movements are needed for this measurement.

Abdomen↗
PubMedDate not supplied

Fetal ultrasound.

Ultrasound provides an opportunity to visualize the fetus and to assess its response to the intrauterine environment. The topic of fetal ultrasound is broad, and whole textbooks have been devoted to areas such as the diagnosis of anomalies. In an effort to provide current practical information, I have focused on the most common clinical questions asked when pregnant women are referred for obstetric ultrasound. We review the diagnoses of oligohydramnios, polyhydramnios, intrauterine growth retardation (IUGR), macrosomia, multiple pregnancy, and common fetal anomalies. Noninvasive assessment of fetal well-being is addressed, along with the use of sonography to refine risk assessment in patients with abnormal antenatal screening tests.

Congenital Abnormalities↗
PubMed2005

Detection of the placental epigenetic signature of the maspin gene in maternal plasma.

The discovery of fetal DNA in the plasma of pregnant women has opened up new approaches for noninvasive prenatal diagnosis and monitoring. Up to now, the lack of a fetal DNA marker that can be universally detected in maternal plasma has limited the clinical application of this technology. We hypothesized that epigenetic differences between the placenta and maternal blood cells could be used for developing such a marker. By using bisulfite DNA sequencing, the methylation status of the maspin gene promoter in placental tissues and paired maternal blood cells from pregnant women was analyzed. The maspin gene promoter was found to be hypomethylated in placental tissues and densely methylated in maternal blood cells. Genotyping of a single nucleotide polymorphism within the unmethylated maspin sequences in maternal plasma demonstrated that these sequences were derived from the fetus. By using real-time quantitative methylation-specific PCR, unmethylated maspin sequences were detected in maternal plasma in all three trimesters of pregnancy and were cleared within 24 h after delivery. The maternal plasma concentration of unmethylated maspin sequences was elevated by a median of 5.7 times in preeclamptic pregnancies compared with nonpreeclamptic pregnancies. Hypomethylated maspin DNA is the first universal marker for fetal DNA in maternal plasma, thus allowing the measurement of fetal DNA concentrations in pregnancy-associated disorders, irrespective of fetal gender and genetic polymorphisms. Differential DNA methylation between the placenta and maternal blood cells may be exploited to develop further markers for noninvasive prenatal assessment.

Adult↗
PubMed2006

Microsatellite markers within --SEA breakpoints for prenatal diagnosis of HbBarts hydrops fetalis.

BACKGROUND: We sought to develop a rapid prenatal diagnostic test for simultaneous detection of HbBarts hydrops fetalis and exclusion of maternal contamination. METHODS: We developed a multiplex quantitative fluorescent PCR (QF-PCR) test that detects the presence/ absence of 2 microsatellite markers (16PTEL05/16PTEL06) located within breakpoints of the Southeast Asia ((-SEA)) deletion. HbBarts hydrops fetalis ((-SEA/-SEA)) is diagnosed by absence of both markers, and maternal contamination of fetal DNA is excluded by absence of noninherited maternal alleles. Fetal and parental DNA samples from 50 families were analyzed in a blinded clinical validation study, and QF-PCR results were compared with their respective molecular genotypes. RESULTS: The multiplex QF-PCR results included correct diagnoses of HbBarts hydrops fetalis in 11 of the fetuses tested, correct verification as unaffected in 20 fetuses, and correct identification as either carriers (alphaalpha/(-SEA)) or unaffected homozygotes in 18. Misidentification as unaffected occurred for 1 carrier. Sensitivity for diagnosis of HbBarts hydrops fetalis was 100% [lower 95% confidence interval, 76.2%], and specificity was 100% (lower 95% confidence interval, 92.6%). None of the samples tested showed any traces of noninherited maternal alleles; thus false-positives because of maternal contamination were eliminated. CONCLUSIONS: In this QF-PCR method, detection of maternally and paternally inherited fetal alleles allowed diagnosis of the double-deletion syndrome, and the ability to differentiate between these alleles allowed simultaneous exclusion of maternal contamination of the fetal genetic material. This novel strategy using cell-free fetal DNA in maternal plasma could form the basis for noninvasive testing for HbBarts hydrops fetalis.

Alleles↗
PubMed1994

Cordocentesis: direct access to the fetal circulation for evaluating fetal wellbeing and thyroid function.

Cordocentesis has pioneered perinatal medicine in the last 10 years with the ability to obtain genetic information, to diagnose and to treat erythrocyte and platelet alloimmunization, to discover the presence of perinatal infections, and to determine the acid-base status of the fetus. Fetal blood sampling has also allowed the perinatologist a greater understanding of fetal physiology, such as thyroid-pituitary function. This review will concentrate on the role of cordocentesis in determining fetal physiology with acid-base status, compare noninvasive testing in its prediction of the hypoxic-acidemic state, and also how cordocentesis has enabled obstretricians to have a better understanding of fetal thyroid development and function.

Acidosis↗
PubMed2006

Endocervical fetal trophoblast for prenatal genetic diagnosis.

PURPOSE OF REVIEW: For over a decade, methods of first-trimester, noninvasive prenatal genetic diagnosis have been actively pursued by many investigators. Isolation of fetal trophoblast from endocervical specimens remains an attractive approach, given the greater numbers of fetal cells than in maternal blood and the better potential for fetal-cell identification based on markers specific for a single cell type (trophoblasts). RECENT FINDINGS: Current studies demonstrate feasibility in identification and molecular analysis of fetal trophoblast cells for prenatal genetic testing. Sampling methods involving lavage, cytobrush, or aspiration of cervical specimens, however, have limitations in the recovery of trophoblasts. SUMMARY: Clinical applications await further systematic studies to determine safety and accuracy in recovery.

Cervix Uteri↗
PubMed1997

Use of positron emission tomography for presurgical localization of eloquent brain areas in children with seizures.

Successful surgical management of a neoplastic or nonneoplastic seizure focus in close proximity to or within eloquent brain areas relies on precise delineation of the relationship between the lesion and functional brain areas. The aim of this series was to validate the usefulness and test the efficacy of noninvasive presurgical PET mapping of eloquent brain areas to predict surgical morbidity and outcome in children with seizures. To identify eloquent brain areas in 15 children (6 female and 9 male; mean age 11 years) with epileptogenic lesions PET images of regional cerebral blood flow were performed following the administration of [(15)O]water during motor, visual, articulation, and receptive language tasks. These images with coregistered magnetic resonance (MR) images were then used to delineate the anatomic relationship of a seizure focus to eloquent brain areas. Additional PET images using [18F]fluoro-2-deoxy-D-glucose (FDG) and [11C]methionine (CMET) were acquired to help localize the seizure focus, as well as characterize the lesion. Patient surgical management decisions were based on PET mapping in combination with coregistered MR images, PET-FDG findings, and the anatomic characteristics of the lesion. At follow-up 1-26 months after surgery, all patients that underwent temporal lobectomy (9 patients) and extratemporal resection (4 patients) for a neoplastic or nonneoplastic seizure focus are seizure-free with minimal postoperative morbidity. Of prime importance, no child sustained a postoperative speech or language deficit. PET imaging was also well tolerated without procedural complications. Based on PET mapping, a nonoperative approach was used for 2 children and a biopsy only was used in one child. When cortical injury involved prenatally determined eloquent cortex, PET demonstrated reorganization of language areas to new adjacent areas or even to the contralateral hemisphere. Integration of anatomical and functional data enhanced the surgical safety, defined optimal surgical approach, delineated the seizure focus from eloquent brain areas, facilitated maximum resection and optimized the timing of surgery, thereby minimizing surgical morbidity while maximizing surgical goals. PET measurements of FDG and CMET uptake were also helpful in localizing the seizure focus and grading the tumors. PET used for brain mapping in children provides the surgeon with strategic preoperative information not readily attainable with traditional invasive Wada testing or intraoperative cortical stimulation. PET mapping may also improve the outcome of extratemporal resections by allowing aggressive seizure focus resection. In addition, serial brain maps may optimize timing for surgical intervention by demonstrating reorganization of eloquent cortex often seen in younger children after cortical injury. Our results suggest that noninvasive presurgical brain mapping has the potential to reduce risk and improve neurologic outcome.

Adolescent↗
PubMed2002

Prediction of fetal D status from maternal plasma: introduction of a new noninvasive fetal RHD genotyping service.

BACKGROUND: Invasive procedures to obtain fetal DNA for prenatal blood grouping present a risk to the fetus. During pregnancy, cell-free fetal DNA is present in maternal blood. The detection of RHD sequences in maternal plasma has been used to predict fetal D status, based on the assumption that RHD is absent in D- genomes. STUDY DESIGN AND METHODS: Real-time PCR assays were designed to distinguish RHD from RHDpsi (possessed by the majority of D- black Africans). Plasma-derived DNA from 137 D- women was subjected to real-time PCR to detect fetal RHD and Y chromosome-associated SRY sequences. The accuracy of RHD genotyping from maternal plasma was investigated by comparing results with those obtained by conventional RHD genotyping from fetal tissue or serologic tests on the infant's RBCs. The quantity of fetal DNA in maternal plasma was investigated in 94 pregnancies. RESULTS: Fetal D status was predicted with 100-percent accuracy from maternal plasma. The number of copies of fetal DNA in maternal plasma was found to increase with gestation. CONCLUSION: Combination of the sensitivity of real-time PCR with an improved RHD typing assay to distinguish RHD from RHDpsi enables highly accurate prediction of fetal D status from maternal plasma. This has resulted in the implementation of a clinical noninvasive fetal RHD genotyping service.

DNA↗
PubMed1989

Umbilical artery Doppler velocimetry as a predictor of fetal hypoxia and acidosis at birth.

We studied the relationship between preoperative umbilical artery Doppler waveforms and umbilical vein pO2 and pH at elective cesarean section. An absence of end-diastolic velocities had a strong statistical association with hypoxia and acidosis, and was an accurate clinical test for hypoxia (sensitivity 78%, specificity 98%, positive predictive value 88%, and negative predictive value 98%) and acidosis (sensitivity 90%, specificity 92%, positive predictive value 53%, and negative predictive value 100%). It was also a clinically sensitive indicator of perinatal morbidity and mortality. Most fetuses with no end-diastolic velocities were growth-retarded, but the reverse was not true. The absence of end-diastolic velocities also divided both mature and immature fetuses into high- and low-risk groups for hypoxia and acidosis. In the presence of end-diastolic velocities, only very high S/D ratios (above 4.5) have any association with hypoxia. As a noninvasive test of fetal umbilical vein pO2 and pH, umbilical artery Doppler performs well.

Acidosis↗
PubMed1983

Enzyme induction in neonates after fetal exposure to antiepileptic drugs.

The 13C-AP breath test is shown to be a convenient, noninvasive method to monitor velocity and capacity of P450-dependent AP N-demethylation in infancy and childhood. According to 13C-AP breath tests, neonates have a very low capacity to eliminate 13CO2, which is only 15 to 21% of the activity in adults. During the first year of life AP N-demethylation increases to reach its maximum at about 2 years; afterwards a slight decrease occurs. In 25 neonates exposed prenatally to different antiepileptic drugs 13C-AP breath test was efficiently used to prove that cytochrome AP N-demethylation was considerably stimulated. After primidone/phenobarbitone, especially in combination with phenytoin, 13C elimination reaches and even surpasses the range for older children. Valproate exposure during fetal life is not consistently followed by a significant increase in AP N-demethylation. The enzyme induction demonstrated by 13C-AP breath test was often accompanied by accelerated metabolic clearance and shortened half-life times of transplacentally acquired antiepileptic drugs. There was good agreement between 13C-AP breath tests and pharmacokinetic data for primidone/phenobarbitone but not for phenytoin. In contrast, in the case of phenytoin exposure during pregnancy the pharmacokinetic parameters and the 13C breath test data will transport very different informations about enzyme induction in these neonates.

Aminopyrine↗
PubMed1995

Serology as a valid screening test for Helicobacter pylori infection in asymptomatic subjects.

Serologic testing is generally accepted as a valid noninvasive screening method for the detection of a Helicobacter pylori infection. To validate serology as an appropriate screening test for H pylori infection in symptom-free subjects, a recent-generation enzyme-linked immunosorbent assay for the detection of H pylori-specific IgG was performed in a large series of asymptomatic women. Blood samples for H pylori serology were taken from 542 apparently healthy women (aged 20 to 40 years) during prenatal screening. In this group, 120 (22.1%) had a positive titer for H pylori. We observed a significantly higher overall prevalence of H pylori seropositivity in nonwhites (62.3%) when compared with Belgian-born whites (17.8%). In both groups there was a significant increase in seropositivity with increasing age. To investigate the correlation between a positive enzyme-linked immunosorbent assay and the actual presence of an active H pylori infection, carbon 13-labeled urea breath tests were performed in 85 seropositive and in 65 randomly selected seronegative subjects. These breath tests were positive in 82 (96.5%) of 85 seropositive and in none of the seronegative subjects, reflecting an actual presence of H pylori in the gastric mucosa of the seropositive women. We conclude that in our population of H pylori-seropositive subjects positive serologic findings correlates extremely well with an active infection with this bacterium. However, because all subjects who were investigated were actually symptom-free, it still should be determined whether these patients should undergo upper gastrointestinal endoscopy and/or be treated with an eradication therapy against H pylori. Further long-term follow-up studies will be required to answer this question.

Adult↗
PubMed1999

Fetal cell recycling: diagnosis of gender and RhD genotype in the same fetal cell retrieved from maternal blood.

OBJECTIVE: Our aim was to develop a new technique, which we have termed fetal cell recycling, that combines the 2 powerful methods of fluorescence in situ hybridization and polymerase chain reaction to maximize the genetic information available from a small number of fetal nucleated erythrocytes obtained noninvasively from the blood of pregnant women. STUDY DESIGN: Blood samples were obtained from 4 Rh-negative women after elective termination of pregnancy at 7 to 17 weeks' gestation. Fetal nucleated erythrocytes were separated by flow sorting with antibody to the gamma chain of fetal hemoglobin. Fluorescence in situ hybridization with chromosome-specific probes was used to diagnose fetal gender. After fluorescence in situ hybridization analysis the fetal nucleated erythrocytes were recycled by a micromanipulation technique and deoxyribonucleic acid diagnosis was performed with polymerase chain reaction amplification of the RhD gene. RESULTS: Among the 4 case patients we detected a total of 101 fetal nucleated erythrocytes. All targeted cells were successfully retrieved with a micromanipulator. In each case we successfully performed both fluorescence in situ hybridization and polymerase chain reaction analysis. The predicted fetal gender and Rh status corresponded to the results obtained from fetal tissue. CONCLUSIONS: Fetal cell recycling combines the powers of highly sensitive molecular methods to maximize the genetic information available from a single fetal cell. This technique will permit noninvasive diagnosis of recessively inherited single-gene disorders.

Aneuploidy↗
PubMed2005

Renal artery stenosis due to fibromuscular dysplasia in an 18-week pregnant woman.

BACKGROUND: Hypertension is a frequent medical complication of pregnancy. Renovascular hypertension is present in 5-10% of cases of severe hypertension during pregnancy. CASE: In this report we describe a 36-year-old woman with severe hypertension caused by bilateral renal artery stenosis due to fibromuscular dysplasia. Guided by the patient's ultrasound findings, only 1 side was treated with angioplasty. Continued labile blood pressure resulted in arteriography of the contralateral renal artery, which confirmed renal artery stenosis was present on the other side. CONCLUSION: Clinicians should maintain a high index of suspicion for renovascular hypertension in pregnancy when drug resistance is present. Because the potential for false-negative results with noninvasive testing for renal artery stenosis is present, if clinical suspicion is high, one should consider using invasive testing.

Adult↗
PubMed2003

Comparison of two-dimensional and three-dimensional ultrasound in the assessment of the cervix to predict preterm delivery.

This study sought to determine whether 3-D transvaginal ultrasound (3D-TVS), compared with the 2-D transvaginal approach (2D-TVS), offers a better identification of some specific features of the uterine cervix that could be useful in the prediction of spontaneous preterm delivery (PTD). A total of 103 women with singleton pregnancies were prospectively evaluated with 2D-TVS and 3D-TVS in the second or third trimester of pregnancy. Statistical analysis was performed with Wilcoxon matched-pairs test, chi2 and Pearson test (p<0.05 was considered significant) and receiver operating characteristic (ROC) curve analysis. Significant differences between these approaches were found for cervical length (p<0.001). A significant correlation was identified between 3D-TVS cervical length and the interval between ultrasound examination and delivery as well as the gestational age at delivery (both p<0.001). ROC curve identified a threshold for 3D-TVS cervical length of 35 mm as an optimal predictor of PTD in the second trimester (sensitivity 100%, specificity 88%). 3D-TVS evaluation of the cervix in pregnancy seems to be an effective, noninvasive method for predicting PTD risk.

Adult↗