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At least 127 records · Page 7Linked to original sources
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↗
PubMed2005

Prenatal fetal sex diagnosis by detecting amelogenin gene in maternal plasma.

OBJECTIVES: To provide a new, reliable noninvasive method for fetal sex determination. METHODS: Fetal sex was detected in 32 early pregnant women by identifying the amelogenin gene in maternal plasma using nested PCR analysis. First, the 122/128 bp of X-Y homologous region containing 6 bp deletions in the intron 3 of amelogenin gene in X chromosome was amplified, and then the nested PCR was carried out, whose 3' end of the upstream primer is just located in the deletion region. The fetus was male or female, depending on whether it had the 89-bp nested PCR product or not. RESULTS: The 89 bp of nested PCR product was detected in 19 plasma samples obtained from pregnant women, deducing they bear the male fetus and the remaining pregnant women bear female. When compared with the birth outcome, two samples were pseudo-positive. The coincidence was 93.8%. This method had high sensitivity that even trace amount of target fetal DNA (10 pg) could be detected. CONCLUSIONS: This conventional nested PCR analysis of amelogenin gene promises to be a reliable method for noninvasive fetal sex determination at early pregnancy using maternal plasma DNA.

Amelogenin↗
PubMed2004

Fetal anemia: new technologies.

PURPOSE OF REVIEW: The purpose of this review is to summarize recently published studies on noninvasive diagnosis of fetal anemia in order to give recommendations for the use of these new tools. RECENT FINDINGS: Red cell alloimmunization remains one of the most common causes of fetal anemia. Amniocentesis and cordocentesis have been used for many years to diagnose fetal anemia due to red cell aloimmunization. These techniques, however, are invasive and many complications are associated with their use. Noninvasive diagnosis of fetal anemia has been performed with Doppler ultrasonography. Based on robust data, several authors recommend the use of middle cerebral artery peak systolic velocity in the management of fetuses at risk for anemia because of red cell alloimmunization. This Doppler parameter can also diagnose fetal anemia due to other conditions. SUMMARY: Middle cerebral artery peak systolic velocity appears to be the best test for the noninvasive diagnosis of fetal anemia. It is important to emphasize that training of sonographers and sonologists is the 'conditio sine qua non' for the correct sampling of the middle cerebral artery.

Amniocentesis↗
PubMed1997

Ultrasonographic fetal cardiac measurement in isoimmunized pregnancies.

OBJECTIVE: To investigate the predictive value of the ultrasonographically measured fetal biventricular outer dimension (BVOD) in diastole in detecting neonatal anemia in pregnancies complicated by isoimmunization. STUDY DESIGN: The records of all patients evaluated for isoimmunization in pregnancy from January 1992 to December 1994 were reviewed retrospectively. The fetal BVOD had been measured with real-time-directed M-mode fetal echocardiography. The BVOD measurement was plotted on a nomogram (with reference to biparietal diameter) and a percentile value determined graphically from the nomogram. Neonatal outcome was obtained prospectively and by chart review. RESULTS: Sixty-three singleton fetuses from the study period who met entry criteria were identified. Anti-D sensitization represented 66% of cases of isoimmunization. Twenty (32%) fetuses required subsequent neonatal transfusion, and 43 (68%) did not. Seventeen fetuses (27%) had BVOD measurements greater than the 95th percentile, and 10 (59%) required subsequent transfusion. Infants in this group also had significantly lower hematocrits at birth (37.7 +/- 13.0% vs. 46.6 +/- 9.0%) and prolonged neonatal intensive care unit stay (10.7 +/- 10.0 vs. 4.7 +/- 3.6 days), respectively, when compared to patients with a BVOD measurement less than the 95th percentile. A BVOD 95th percentile threshold had a sensitivity, specificity and positive predictive value of 50%, 84% and 59%, respectively, in predicting the need for neonatal transfusion. CONCLUSION: In patients with isoimmunization, a BVOD measurement in the 95th percentile or greater was associated with a relatively high likelihood of neonatal anemia and transfusion. Although the measurement is not sufficiently sensitive to be used as a single parameter in predicting neonatal compromise in these patients, it can be a useful, noninvasive adjunct to the management of isoimmunized pregnancies.

Anemia, Neonatal↗
PubMed2005

Evaluating suspected fetal anemia with Doppler ultrasound.

OBJECTIVE: To evaluate Doppler studies of the fetal middle cerebral artery to predict fetal or neonatal anemia. STUDY DESIGN: The perinatal database at one institution was searched for all patients evaluated for suspected fetal anemia. Middle cerebral artery peak velocity measurements just prior to cordocentesis or the last measurement prior to delivery was used for analysis. The primary outcome data analyzed were fetal or neonatal hematocrit at the time of the cordocentesis or delivery. RESULTS: During the study period there were 36 patients who met the inclusion criterion. There was a significant correlation between middle cerebral artery peak velocity and fetal or neonatal hematocrit. CONCLUSION: Peak flow velocity in the middle cerebral artery is an accurate, noninvasive clinically useful method of evaluating suspected fetal anemia.

Adult↗
PubMed2005

Noninvasive prenatal diagnosis of fetal Rhesus D: ready for Prime(r) Time.

Rhesus (Rh) D blood group incompatibility between the pregnant woman and her fetus is a significant problem due to the possibility of maternal alloimmunization and consequent hemolytic disease of the newborn. The RhD-negative blood group is found in 15% of whites, 3-5% of black Africans, and is rare in Asians. Advances in both our understanding of the RHD locus and its variants, as well as technical improvements in the extraction and amplification of cell-free fetal DNA in maternal plasma, have led to incorporation of noninvasive diagnosis of RHD genotype into routine prenatal care in the United Kingdom, France, and the Netherlands. In this commentary we examine the experience to date with large-scale clinical trials performed in the European Union, describe approaches to reduce false-positive and false-negative results, and review ongoing research to standardize assays and reduce costs using automated assays. False-negative cases are mainly due to either a lack of fetal DNA in the maternal sample due to early gestation or insensitive methods. False-positive cases are due to genotypic variants observed in individuals of African ancestry. Noninvasive prenatal diagnosis of fetal Rhesus D genotype is sensitive and accurate and has been widely validated in Europe. The United States should begin to undertake clinical trials to bring this technology to patient care as soon as possible.

Erythroblastosis, Fetal↗
PubMed2006

Plasma epigenetic markers for cancer detection and prenatal diagnosis.

Successful detection of circulating nucleic acids has opened up new possibilities in cancer testing and prenatal diagnosis. Circulating DNA markers are useful in cancer detection, prognostication and monitoring. Cancer-associated molecular changes which can be detected include gene mutations, chromosomal rearrangements, microsatellite alterations, viral sequences, and, to be discussed in more detailed, gene promoter hypermethylation. Methylation analysis is commonly performed by DNA digestion with methylation-sensitive restriction endonucleases followed by polymerase chain reaction (PCR), or bisulfite modification followed by methylation-specific PCR (MSP). The detection of fetal DNA in maternal plasma has opened up new possibilities for noninvasive prenatal diagnosis. However, circulating fetal DNA detection has been based on exploiting gender and polymorphic differences between the fetus and mother. The recent discovery of epigenetic differences between the maternal and the fetal DNA detectable in maternal plasma has launched a hunt for fetal-derived epigenetic markers in maternal plasma. It is hoped that this type of universally applicable markers would be made available in a clinical diagnostic setting in the near future.

DNA↗
PubMed1995

Management of the growth-restricted fetus: the role of noninvasive tests and fetal blood sampling.

OBJECTIVE: To assess the accuracy of two noninvasive tests, the nonstress test (NST) and Doppler velocimetry of the umbilical artery, in predicting fetal acidemia or hypoxia demonstrated by funipuncture, and to determine any association between acidemia or hypoxia and perinatal outcome. METHODS: The study included 112 consecutive growth-restricted fetuses diagnosed by ultrasonography between 26-39 weeks' gestation. For Doppler sonograms, the absence of end-diastolic flow was considered pathologic. Acidemia and hypoxia were defined as a pH and an oxygen pressure (PO2) below the fifth percentile at the given gestational age. The fetuses were classified according to the results obtained by the different tests (Doppler velocimetry, NST, cord blood gases). RESULTS: Fetuses with one or both noninvasive tests abnormal (group A, N = 32) had a significantly lower mean gestational age at sampling than those fetuses with both noninvasive tests normal (group B, N = 80). Mean pH and PO2 values for groups A and B were significantly different. Obstetric and perinatal data were collected, and a statistically significant difference was demonstrated between those with a pH and/or PO2 below the fifth percentile and those with a pH and PO2 above the fifth percentile for all indices except birth weight below the tenth percentile. CONCLUSION: Fetal growth restriction is a benign condition in physically normal fetuses if both noninvasive tests and pH and PO2 measured by funipuncture are normal in the absence of maternal pathology. One single fetal blood analysis for pH and PO2 helped separate groups having different obstetric and neonatal outcomes.

Female↗
PubMed2005

First trimester ultrasound screening for fetal aneuploidy and middle cerebral artery Doppler assessment for fetal alloimmunization.

PURPOSE OF REVIEW: Traditional methods of fetal evaluation require invasive procedures (e.g. amniocentesis) with an inherent, albeit low, risk of complications and pregnancy loss. As medical knowledge and ultrasound technology have advanced, noninvasive modes of fetal evaluation have become increasingly used. Two disorders in which this has been most applied are fetal aneuploidy and alloimmunization to red blood cell antigens. RECENT FINDINGS: First-trimester screening protocols for fetal aneuploidy combine ultrasound measurement of the fetal nuchal translucency with the measurement of two maternal serum hormones, free beta-human chorionic gonadotropin and pregnancy-associated plasma protein-A. This combination detects approximately 85% of women pregnant with fetuses with trisomy 21. An increase in the velocity of fetal middle cerebral artery blood flow occurs in the setting of moderate to severe fetal anemia and can be measured with Doppler ultrasound. Middle cerebral artery evaluation is equally sensitive in the prediction of anemia as amniocentesis for bilirubin breakdown products and has less associated risk. It has an additional benefit because it can also be applied to causes of anemia other than hemolysis. SUMMARY: Noninvasive methods of fetal assessment are becoming increasingly commonplace. There has been a dramatic decrease in the use of prenatal diagnostic services as screening strategies have become available. Doppler assessment of the velocity of blood flow through the fetal middle cerebral artery will allow for more judicious application of invasive procedures to pregnancies at significant risk for anemia.

Aneuploidy↗
PubMed1999

[A noninvasive approach to studying fetal cells for prenatal diagnosis of chromosomal aneuploidies].

Fetal cells isolated from maternal peripheral blood during the second trimester of pregnancy were analyzed. Blood samples were centrifuged in a Ficoll-Paque gradient, the mononuclear cell fraction was isolated and stained with fluorescent monoclonal antibodies against glycophorine A (GPA + PE), transferrin (CD71 + FITC), and Hoechst 33342. Fluorescence-activated cell sorting (FACS) was conducted on a Vantage flow cytofluorimeter (Becton Dickinson). Fluorescence in situ hybridization (FISH) with Y chromosome-specific DNA probe revealed fetal cells that exhibited Y signal in all 20 blood samples obtained from women pregnant with healthy male fetuses. The concentration of these fetal cells averaged about 1.34% and ranged from 0.1 to 4.2% in different blood samples. In six cases, blood samples were obtained from pregnant women, in which prenatal cytogenetic analysis revealed various fetal aneuploidies. Using FISH with DNA probes specific for chromosomes X, 18, and 13/21, Fetal cells with chromosomal aberrations were detected in these six maternal blood samples at a concentration from 1.5 to 5.6% (on average 3.7%). These results indicate the possibility of a new noninvasive approach, which is safe for both mother and fetus when used for isolation of fetal cells from pregnant women's blood samples and prenatal diagnosis of a broad spectrum of fetal cell chromosomal aberrations.

Aneuploidy↗
PubMed1999

Value of inferior vena cava Doppler waveform analysis for prediction of neonatal outcome.

The objective of this article is to determine the value of the inferior vena cava preload index (IVC) to predict neonatal outcome and compare it to other biophysical methods of antenatal surveillance. A clinical outcome study of patients referred to the author's institution for Doppler velocity blood flow studies was undertaken by comparing the ability of three antenatal surveillance tests: the nonstress test (NST); umbilical artery S/D ratio (UA); and the ratio of the middle cerebral artery to umbilical artery S/D ratios (MCUA) to predict poor neonatal outcome to the ability of the IVC to predict poor outcome. Patients were followed serially and neonatal outcome data was tabulated. Those patients that delivered within 10 days of their last study were included in the analysis. Seventy patients met the inclusion criterion. Neonatal outcome based on the results of the IVC as compared with outcome based on the results of the NST, UA, and MCUA tests. Odds ratios (with 95% confidence limits) for significant neonatal morbidity predicted by each test were: NST: 2.6 (0.14-14.6); UA: 5.7 (1.7-18.8); MCUA: 3.6 (1.1-13.1); and IVC: 4.1 (1.3-13.2). Logistic regression analysis indicated that the combination of MCUA and IVC was the best method of predicting poor neonatal outcome. This study of the utility of fetal IVC suggests that this noninvasive method of antenatal surveillance may provide an additional sensitive method of evaluating the status of the high-risk fetus.

Blood Flow Velocity↗
PubMed2000

How to diagnose preterm labor: a clinical dilemma.

The clinician is faced with many dilemmas in the diagnosis of preterm labor. The tools at hand (no pun intended) yield subjective information and it is difficult to distinguish true labor from false labor. Because preterm labor is multifactorial in cause and can occur in primiparas, estimating risk for the individual patient is difficult. The cause of the preterm labor in the majority of patients is idiopathic; in this group, the use of salivary estriol as a biochemical marker for preterm labor can increase the accuracy of the diagnosis of true labor. It may also lend confidence to the diagnosis of false labor and may allay anxiety and prevent unnecessary interventions. On the horizon are two noninvasive methods: the EMG, to evaluate uterine contractility, and the collascope, to evaluate the cervix. Both show promise and may provide a more objective assessment of risk for preterm delivery among women with symptoms of preterm labor.

Collagen↗
PubMed1997

Prenatal diagnosis using fetal cells from the maternal circulation.

Current prenatal diagnosis relies on invasive methods such as amniocentesis and chorionic villus sampling. Because these methods carry a low, but finite risk of pregnancy loss, noninvasive genetic screening techniques are the focus of intense research. Isolating fetal cells from maternal blood for genetic analysis is the least invasive method currently being investigated. We discuss the various methods that have been used to isolate these cells. Nucleated red blood cells have emerged as the ideal fetal cell type. This is because they have the DNA material necessary for genetic analysis, they are consistently present in maternal blood, they can be easily identified based on their morphology, and they have a definite gestational life span.

Congenital Abnormalities↗
PubMed2004

Size distributions of maternal and fetal DNA in maternal plasma.

BACKGROUND: The discovery of fetal DNA in maternal plasma has opened up an approach for noninvasive prenatal diagnosis. Despite the rapid expansion in clinical applications, the molecular characteristics of plasma DNA in pregnant women remain unclear. METHODS: We investigated the size distribution of plasma DNA in 34 nonpregnant women and 31 pregnant women, using a panel of quantitative PCR assays with different amplicon sizes targeting the leptin gene. We also determined the size distribution of fetal DNA in maternal plasma by targeting the SRY gene. RESULTS: The median percentages of plasma DNA with size >201 bp were 57% and 14% for pregnant and nonpregnant women, respectively (P <0.001, Mann-Whitney test). The median percentages of fetal-derived DNA with sizes >193 bp and >313 bp were 20% and 0%, respectively, in maternal plasma. CONCLUSION: Plasma DNA molecules are mainly short DNA fragments. The DNA fragments in the plasma of pregnant women are significantly longer than those in the plasma of nonpregnant women, and the maternal-derived DNA molecules are longer than the fetal-derived ones.

DNA↗
PubMed2000

Sonographic methods to detect fetal anemia in red blood cell alloimmunization.

Published reports, case studies, and articles from the English language regarding ultrasonographic detection of fetal anemia in red blood cell alloimmunization were obtained from a MEDLINE search from 1966 to November 1999 using the keywords Rh disease, hemolytic disease of the newborn, ultrasound, and Doppler flow studies and combinations thereof. All articles were cross-referenced. Ultrasound techniques including early findings associated with immune hydrops fetalis, multiple morphologic ultrasound markers, and Doppler flow studies that have been used to detect fetal anemia are reviewed and critically evaluated. Noninvasive sonographic techniques may reduce the number of invasive procedures that traditionally are used to follow fetuses at risk for anemia and decrease the associated risks from these procedures.

Blood Flow Velocity↗
PubMed2006

Diagnostic accuracy of noninvasive fetal Rh genotyping from maternal blood--a meta-analysis.

OBJECTIVE: The purpose of this study was to determine the reported diagnostic accuracy, the validity, and the current limitations of fetal Rh genotyping from peripheral maternal blood based on the existing English-written publications. STUDY DESIGN: A search of the English literature describing fetal RhD determination from maternal blood was conducted. From each study, we determined the number of samples tested, fetal RhD genotype, the source of the fetal DNA (maternal plasma, serum, or fetal cells), gestational age, and confirmation of fetal Rh type. The presence of alloimmunization and exclusions of tested samples were noted. For the meta-analysis we calculated composite estimates using 2 random effects models, weighted GLM and Bayesian. Sensitivity, specificity, positive and negative predictive values were calculated. RESULTS: We identified 37 English-written publications that included 44 protocols reporting noninvasive Rh genotyping using fetal DNA obtained from maternal blood on a total of 3261 samples. A total of 183 (183/3261, 5.6%) samples were excluded from the meta-analysis. The overall diagnostic accuracy after exclusions was 94.8%. The gestational ages ranged between 8 and 42 weeks gestation. Maternal serum and plasma were found to be the best source for accurate diagnosis of fetal RhD type in 394/410 (96.1%) and 2293/2377 (96.5%), respectively. There were 719/783 (91.8%) alloimmunized patients that were correctly diagnosed. There were 16 studies that reported 100% diagnostic accuracy in their fetal RhD genotyping. CONCLUSION: The diagnostic accuracy of noninvasive fetal Rh determination using maternal peripheral blood is 94.8%. Its use can be applicable to Rh prophylaxis and to the management of Rh alloimmunized pregnancies. Improvements of the technique and further study of structure and rearrangements of the RhD gene may improve accuracy of testing and enable large-scale, risk-free fetal RhD genotyping using maternal blood.

DNA↗
PubMed2001

Noninvasive techniques to detect fetal anemia due to red blood cell alloimmunization: a systematic review.

OBJECTIVE: To estimate, in maternal red blood cell alloimmunization, the diagnostic value of fetal ultrasonography and Doppler blood flow velocity in the evaluation and prediction of fetal anemia. METHODS: Literature from 1970 to 2000 was identified using general bibliographic databases (MEDLINE and EMBASE), the Cochrane Library and relevant specialist register of the Cochrane Collaboration, and by checking reference lists of known primary and review articles. Studies were selected if the accuracy of the fetal ultrasound parameters or Doppler studies of blood flow in the fetal vessels was estimated compared with a reference standard (fetal hemoglobin). The diagnostic tests evaluated were ultrasound measurement of the fetal spleen perimeter and Doppler studies of blood velocity estimates in the umbilical vein, ductus venosus, middle cerebral artery, thoracic aorta, and umbilical vessel combined with the thoracic aorta. Study selection, quality assessment, and data abstraction were performed independently and in duplicate. Data from the selected studies were abstracted as 2 x 2 tables comparing the diagnostic test result with the reference standard. Diagnostic accuracy was expressed as likelihood ratios. RESULTS: The review included eight primary studies with 362 pregnancies affected by red cell alloimmunization. Prospective patient recruitment and complete population details were reported in half of the selected studies (four of eight). Only one study reported masking the diagnostic test results to clinicians. The diagnostic test performance varied widely according to the type of the test evaluated and the cutoff level used to define fetal anemia, which varied from study to study. The diagnostic test study of highest methodological quality reported a positive likelihood ratio of 8.45 (95% confidence interval 4.69, 15.56) and negative likelihood ratio of 0.02 (95% confidence interval 0.001, 0.25) for maximum middle cerebral artery Doppler velocity. CONCLUSION: The literature reporting noninvasive techniques to predict fetal anemia is methodologically poor and a standard approach to the evaluation of these techniques is lacking. A recommendation for practice cannot be generated without further rigorous research.

Blood Flow Velocity↗
PubMed2003

Preliminary report on a new and noninvasive method for the assessment of fetal lung maturity.

OBJECT: Several patterns of fetal breathing movements (FBMs), i.e. abdominal wall movements (AWm), thoracic wall movements (TWm) and nasal fluid flow velocity waveforms (NFFVW), were investigated by ultrasound (US) technology and related to fetal pulmonary maturity and immaturity, i.e. fetal lung maturity (FLM) tests, in order to validate the hypothesis that they may indicate whether the fetal lung is mature or immature, regardless of gender, weight and gestational age. MATERIAL AND METHODS: We prospectively enrolled 143 high-risk pregnancies in which a complete US study of FBMs and FLM tests was performed. Among them 43 women satisfied the inclusion criteria. US-FLM was defined as the presence of regular NFFVW detected by pulsed Doppler and spectral analysis, or irregular NF-FVW synchronous with TWm detected by M-mode. An US guided amniocentesis was performed in order to collect amniotic fluid (AF) and FLM was evaluated by L/S (lecithin/sphingomyelin) determination, presence of phosphatidylglycerol (PG) and lamellar bodies (LBs) count. At the end of the study the diagnostic accuracy of US-FLM was compared to that of FLM tests. RESULTS: Diagnostic accuracy for US evaluation of FLM was as follows: sensitivity: 89.6%; specificity: 85.7%; PPV: 92.8%; NPV: 80%. Diagnostic accuracy of FLM tests was as follows: sensitivity: 100%; specificity: 51.7%; PPV: 100%; NPV: 50%. L/S determination predicted lung maturity with a sensitivity of 100%; specificity of 93.1%; PPV of 100%; NPV of 87.5%. CONCLUSION: Presence of regular NFFVW or irregular NFFVW and TWm correlate accurately with conventional FLM tests. We suggest that this noninvasive procedure may be helpful for assessing FLM, particularly under certain circumstances, e.g., oligo-anhydramnios, laboratory logistic equipment difficulties or heavily stained AF samples, amniocentesis refusal, religious concerns.

Amniocentesis↗