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Biomedical subjects

Mary E D'Alton

Publications and source records attributed to Mary E D'Alton.

At least 19 recordsLinked to original sources
PubMed2006

Stability of first- and second-trimester serum markers after storage and shipment.

OBJECTIVE: The purpose of this study was to examine the levels of first- and second-trimester maternal serum markers used in Down syndrome screening in relation to the time between sample collection and arrival at the laboratory. METHODS: The FASTER trial, designed to compare first- and second-trimester screening tests for aneuploidy, has recently been completed, having recruited more than 38,000 patients. According to the trial protocol, all blood samples were drawn in serum separator tubes, centrifuged within 30 min and stored at 4 degrees C until shipment by air express. To examine the effect of delayed shipment, serum marker levels (expressed as multiple of the median--MoM) were evaluated in the first- and second-trimester samples and stratified by the number of days between serum collection and laboratory receipt. RESULTS: Under specified collection and shipment conditions, first and second-trimester screening marker mean levels and degrees of variance were stable for up to 9 days, with the exception of unconjugated estriol, which was stable for up to 6 days. CONCLUSION: The levels of first- and second-trimester Down syndrome screening markers can be measured reliably when the sample is centrifuged, refrigerated until shipment and received in the laboratory within a week of being drawn. A conservative approach would be to restrict testing to within 6 days of draw, with the intent to keep shipping delays to a minimum.

Biomarkers↗
PubMed2006

Is there a nuchal translucency millimeter measurement above which there is no added benefit from first trimester serum screening?

OBJECTIVE: The purpose of this study was to evaluate whether there is a nuchal translucency (NT) measurement, independent of gestational age, above which immediate diagnostic testing should be offered without waiting for first trimester serum markers. STUDY DESIGN: Thirty-six thousand one hundred twenty patients had successful measurement of simple NT at 10 3/7 to 13 6/7 weeks and had first trimester serum screening. No risks were reported until second trimester serum screening was completed. RESULTS: Thirty-two patients (0.09%) had NT > or = 4.0 mm; the lowest combined first trimester trisomy 21 risk assessment in euploid cases was 1 in 8 and among aneuploidy cases was 7 in 8. One hundred twenty-eight patients (0.3%) had simple NT > or = 3.0 mm: the lowest combined first trimester trisomy 21 risk assessment of any patient in this group was 1 in 1479 and the lowest risk assessment among aneuploid cases was 1 in 2. Ten patients (8%) had first trimester trisomy 21 risk assessments lowered to less that 1:200 and none of these 10 cases had an abnormal outcome. CONCLUSION: During first trimester Down syndrome screening, whenever an NT measurement of 3.0 mm or greater is obtained there is minimal benefit in waiting for serum screening results, and no benefit for NT of 4.0 mm or greater. Differentiation between cystic hygroma and enlarged simple NT (> or = 3.0 mm) is now a moot point as both are sufficiently high risk situations to warrant immediate CVS.

Chorionic Gonadotropin, beta Subunit, Human↗
PubMed2006

The impact of multiple gestations on late preterm (near-term) births.

Multiple pregnancies currently account for 3% of all births in the United States but are disproportionately responsible for larger rates of prematurity and significant neonatal morbidity. The mean birth age for most multi-fetal pregnancies occurs during the late preterm period when both spontaneous preterm labor and iatrogenic premature birth because of obstetrical or maternal complications are common. Multiples pose numerous unique challenges, emphasizing the significant impact of plurality on late preterm births.

Female↗
PubMed2006

Multiple gestations and late preterm (near-term) deliveries.

Multiple gestations present unique challenges to the modern obstetrician. Many twin and high-order multiple pregnancies are delivered between 34 and 37 weeks' gestation either secondary to preterm labor or obstetrical complications necessitating intervention. Recognizing the increasing prevalence of multiple gestations and the impact of late preterm deliveries in modern practice, this review analyzes the impact of multiple pregnancies on perinatal outcomes, reviews the strategies to prevent preterm labor, and summarizes potential indications for late preterm delivery. In this paper, "late preterm" has been used instead of "near-term," as the former was considered more appropriate to reflect this subgroup of preterm infants in a workshop on this topic held in July 2005, organized by the National Institute of Child Health and Human Development.

Female↗
PubMed2006

Postterm pregnancy: practice patterns of contemporary obstetricians and gynecologists.

The purpose of this study was to determine the management of postterm pregnancy by contemporary practicing obstetricians. A questionnaire investigating practice patterns pertaining to postterm pregnancy was mailed to 1000 randomly selected American College of Obstetricians and Gynecologists (ACOG) Fellows and Junior Fellows in March 2004. The response rate was 52.2% (522/1000). Statistical analysis included the answers from the 420 practicing obstetricians. Males comprised 55.7% (234/420) of the responding obstetricians. The majority of responding obstetricians (95.4%) rated their residency training regarding management of postterm pregnancy as adequate or comprehensive. Forty-eight percent define postterm pregnancy as 42 weeks gestation or greater, whereas 43.1% consider 41 weeks gestation or greater to be postterm. Seventy-three percent routinely induce low-risk patients with singletons at 41 weeks gestation. If patients decline induction at 41 weeks or if the practitioner does not induce patients until after 41 weeks gestation, the majority of respondents (64.8% and 65.0%, respectively) start postterm pregnancy fetal testing in singletons at 41 weeks and obtain testing twice weekly. Most (64.6%) use cervical ripening agents when inducing both nulliparous and multiparous patients with unfavorable cervices. The majority of practitioners (97.3%) do not use prostaglandins when inducing postterm patients with one previous cesarean delivery. Although most respondents manage postterm pregnancy according to recent ACOG educational materials with regard to antenatal fetal surveillance and methods of induction, the majority induce patients with singleton postterm pregnancies at 41 weeks gestation rather than at 42 weeks gestation.

Female↗
PubMed2006

Screening for Down syndrome: practice patterns and knowledge of obstetricians and gynecologists.

OBJECTIVE: To assess obstetricians' practice patterns and knowledge regarding screening for Down syndrome. METHODS: A questionnaire was mailed to 1,105 American College of Obstetricians and Gynecologists Fellows and Junior Fellows in 2004. RESULTS: Sixty percent of questionnaires were returned. Statistical analyses were limited to the 532 practicing obstetricians. Greater than 80% felt their training and experience qualified them to counsel patients about genetic issues in pregnancy. However, 45% rated their residency training regarding prenatal diagnosis as barely adequate or nonexistent. American College of Obstetricians and Gynecologists publications were rated by 86% as an important source of information on genetic counseling. Seventy-eight percent of practitioners counsel all obstetric patients about risks for fetal aneuploidy, and 67% provide counseling for heritable genetic abnormalities. Although the majority (99%) offer second-trimester Down syndrome screening, only 55% also offer first-trimester screening for Down syndrome. Almost one half (49%) use the quad screen, and 6% offer integrated first- and second-trimester screening. The majority (88%) routinely offer amniocentesis to patients who are at elevated risk for genetic abnormalities, whereas 44% also offer chorionic villus sampling. Few (2%) perform chorionic villus sampling. CONCLUSION: Most obstetricians manage patients at risk for fetal genetic abnormalities according to American College of Obstetricians and Gynecologists educational materials. This survey identified deficiencies related to Down syndrome screening, including a limited number of practitioners performing chorionic villus sampling and physicians' own perception that training regarding genetic counseling should be improved. Educational strategies are needed to address these deficiencies before first-trimester screening programs are widely implemented. LEVEL OF EVIDENCE: III.

Amniocentesis↗
PubMed2006

Aneuploidy screening: what test should I use?

Screening for the risk of fetal aneuploidy can be effectively performed in either the first or second trimester. When obtained independently, the interpretation of those data is straightforward. However, the effectiveness of screening can be enhanced by combining studies performed in each trimester in a variety of ways. In this commentary we will define and discuss both the advantages and disadvantages of using integrated, stepwise, sequential or contingency screening for risk assessment of fetal aneuploidy.

Adult↗
PubMed2006

Early access to prenatal care: implications for racial disparity in perinatal mortality.

OBJECTIVE: To investigate racial disparities in perinatal mortality in women with early access to prenatal care. METHODS: A prospectively collected database from a large, multicenter investigation of singleton pregnancies, the FASTER trial, was queried. Patients were recruited from an unselected obstetric population between 1999 and 2002. A total of 35,529 pregnancies with early access to prenatal care were reviewed for this analysis. The timing of perinatal loss was assessed. The following intervals were evaluated: fetal demise at less than 24 weeks of gestation, fetal demise at 24 or more weeks of gestation, and neonatal demise. Perinatal mortality was defined as the sum of these three intervals. RESULTS: The study population was 5% black, 22% Hispanic, 68% white, and 5% other. All minority races experienced higher rates of intrauterine growth restriction, preeclampsia, preterm premature rupture of membranes, gestational diabetes, placenta previa, preterm birth, very-preterm birth, cesarean delivery, light vaginal bleeding, and heavy vaginal bleeding compared with the white population. Overall perinatal mortality was 13 per 1,000 (471/35,529). The adjusted odds ratios (95% confidence intervals) for perinatal mortality (utilizing the white population as the referent race) were: black 3.5 (2.5-4.9), Hispanic 1.5 (1.2-2.1), and other 1.9 (1.3-2.8). CONCLUSION: Racial disparities in perinatal mortality persist in contemporary obstetric practice despite early access to prenatal care. LEVEL OF EVIDENCE: II-2.

Black or African American↗
PubMed2006

Pregnancy loss rates after midtrimester amniocentesis.

OBJECTIVE: The purpose of this study was to quantify the contemporary procedure-related loss rate after midtrimester amniocentesis using a database generated from patients who were recruited to the First And Second Trimester Evaluation of Risk for Aneuploidy trial. METHODS: A total of 35,003 unselected patients from the general population with viable singleton pregnancies were enrolled in the First And Second Trimester Evaluation of Risk for Aneuploidy trial between 10 3/7 and 13 6/7 weeks gestation and followed up prospectively for complete pregnancy outcome information. Patients who either did (study group, n=3,096) or did not (control group, n=31,907) undergo midtrimester amniocentesis were identified from the database. The rate of fetal loss less than 24 weeks of gestation was compared between the two groups, and multiple logistic regression analysis was used to adjust for potential confounders. RESULTS: The spontaneous fetal loss rate less than 24 weeks of gestation in the study group was 1.0% and was not statistically different from the background 0.94% rate seen in the control group (P=.74, 95% confidence interval -0.26%, 0.49%). The procedure-related loss rate after amniocentesis was 0.06% (1.0% minus the background rate of 0.94%). Women undergoing amniocentesis were 1.1 times more likely to have a spontaneous loss (95% confidence interval 0.7-1.5). CONCLUSION: The procedure-related fetal loss rate after midtrimester amniocentesis performed on patients in a contemporary prospective clinical trial was 0.06%. There was no significant difference in loss rates between those undergoing amniocentesis and those not undergoing amniocentesis. LEVEL OF EVIDENCE: II-2.

Abortion, Spontaneous↗
PubMed2006

Comparison of serum markers in first-trimester down syndrome screening.

OBJECTIVE: To estimate patterns of total hCG and inhibin A levels in the late first trimester of Down syndrome pregnancies, compare them with that of free beta-hCG, and assess screening performance of these markers individually and in combination with pregnancy-associated plasma protein-A (PAPP-A) and nuchal translucency. METHODS: Seventy-nine matched case-control sets of maternal serum samples (each Down syndrome case matched to 5 controls) from 11 through 13 completed weeks of gestation were taken from the sample bank of the First and Second Trimester Evaluation of Risk Consortium, a population-based study, and assayed for levels of free beta-hCG, total hCG, and inhibin A. Distribution characteristics and correlations of the multiples of the median values were estimated in cases and controls. Screening performance for each marker, alone and in combination with PAPP-A, nuchal translucency, and maternal age, was calculated. RESULTS: Median multiples of the median levels of free beta-hCG, total hCG, and inhibin A in cases were more elevated as gestation increased from 11 to 13 weeks, with univariate detection rates of 31%, 23%, and 29%, respectively, at a 5% false-positive rate. At 12 weeks, the multivariate detection rates at a 5% false-positive rate for nuchal translucency and PAPP-A (with maternal age) with either free beta-hCG, total hCG, or inhibin A were 84%, 83%, and 85%, respectively. The improvement in performance from nuchal translucency and PAPP-A to any of the three-marker tests was significant, while performance of any of the three-marker combinations was not significantly different from each other. CONCLUSION: Although levels of free beta-hCG in affected pregnancies were higher earlier than the levels of either total hCG or inhibin A, there was no significant difference in screening performance when either of the three markers was used with nuchal translucency and PAPP-A at 11-13 weeks of pregnancy. LEVEL OF EVIDENCE: II-2.

Adult↗
PubMed2006

The National Children's Study: a 21-year prospective study of 100,000 American children.

Prospective, multiyear epidemiologic studies have proven to be highly effective in discovering preventable risk factors for chronic disease. Investigations such as the Framingham Heart Study have produced blueprints for disease prevention and saved millions of lives and billions of dollars. To discover preventable environmental risk factors for disease in children, the US Congress directed the National Institute of Child Health and Human Development, through the Children's Health Act of 2000, to conduct the National Children's Study. The National Children's Study is hypothesis-driven and will seek information on environmental risks and individual susceptibility factors for asthma, birth defects, dyslexia, attention-deficit/hyperactivity disorder, autism, schizophrenia, and obesity, as well as for adverse birth outcomes. It will be conducted in a nationally representative, prospective cohort of 100,000 US-born children. Children will be followed from conception to 21 years of age. Environmental exposures (chemical, physical, biological, and psychosocial) will be assessed repeatedly during pregnancy and throughout childhood in children's homes, schools, and communities. Chemical assays will be performed by the Centers for Disease Control and Prevention, and banks of biological and environmental samples will be established for future analyses. Genetic material will be collected on each mother and child and banked to permit study of gene-environment interactions. Recruitment is scheduled to begin in 2007 at 7 Vanguard Sites and will extend to 105 sites across the United States. The National Children's Study will generate multiple satellite studies that explore methodologic issues, etiologic questions, and potential interventions. It will provide training for the next generation of researchers and practitioners in environmental pediatrics and will link to planned and ongoing prospective birth cohort studies in other nations. Data from the National Children's Study will guide development of a comprehensive blueprint for disease prevention in children.

Child↗
PubMed2005

First-trimester or second-trimester screening, or both, for Down's syndrome.

BACKGROUND: It is uncertain how best to screen pregnant women for the presence of fetal Down's syndrome: to perform first-trimester screening, to perform second-trimester screening, or to use strategies incorporating measurements in both trimesters. METHODS: Women with singleton pregnancies underwent first-trimester combined screening (measurement of nuchal translucency, pregnancy-associated plasma protein A [PAPP-A], and the free beta subunit of human chorionic gonadotropin at 10 weeks 3 days through 13 weeks 6 days of gestation) and second-trimester quadruple screening (measurement of alpha-fetoprotein, total human chorionic gonadotropin, unconjugated estriol, and inhibin A at 15 through 18 weeks of gestation). We compared the results of stepwise sequential screening (risk results provided after each test), fully integrated screening (single risk result provided), and serum integrated screening (identical to fully integrated screening, but without nuchal translucency). RESULTS: First-trimester screening was performed in 38,167 patients; 117 had a fetus with Down's syndrome. At a 5 percent false positive rate, the rates of detection of Down's syndrome were as follows: with first-trimester combined screening, 87 percent, 85 percent, and 82 percent for measurements performed at 11, 12, and 13 weeks, respectively; with second-trimester quadruple screening, 81 percent; with stepwise sequential screening, 95 percent; with serum integrated screening, 88 percent; and with fully integrated screening with first-trimester measurements performed at 11 weeks, 96 percent. Paired comparisons found significant differences between the tests, except for the comparison between serum integrated screening and combined screening. CONCLUSIONS: First-trimester combined screening at 11 weeks of gestation is better than second-trimester quadruple screening but at 13 weeks has results similar to second-trimester quadruple screening. Both stepwise sequential screening and fully integrated screening have high rates of detection of Down's syndrome, with low false positive rates.

Adult↗
PubMed2005

First trimester uterine artery Doppler abnormalities predict subsequent intrauterine growth restriction.

OBJECTIVE: This study was undertaken to evaluate the association between uterine artery Doppler velocimetry performed between 10 and 14 weeks gestation and intrauterine growth restriction (IUGR). STUDY DESIGN: Uterine artery Doppler velocimetry data were collected on 1067 women enrolled in the FASTER trial at the University of Colorado site. The data were analyzed by using univariate and multivariable logistic regression analysis. RESULTS: The uterine artery mean resistance index (RI) for the entire cohort was equal on the right and left sides (0.59 +/- 0.14). Of the 1067 women, 34.2% had unilateral or bilateral diastolic notches, 1 notch was observed in 23.8%, and bilateral notches in 10.4%. Women with a high uterine artery mean RI (> or = 75th percentile) were 5.5 times more likely to have IUGR (95% CI 1.6-18.7). There was no significant relationship between notching and IUGR. CONCLUSION: Elevated first trimester uterine artery mean RI is significantly associated with IUGR.

Adult↗
PubMed2005

Prenatal diagnosis and multiple pregnancy.

The incidence of twins, triplets, and high-order multiples has increased dramatically in the last two decades secondary to greater reliance on fertility treatments and to delayed childbearing. Offspring of a multiple gestation are at increased risk for both chromosomal and structural abnormalities. Prenatal diagnosis in these patients is challenging. Options for screening tests are limited. Invasive diagnostic procedures are complex. Likewise, physicians and patients may be faced with the dilemma of deciding how to manage discordant results. The following paper will review the unique concerns associated with prenatal diagnosis in a multiple pregnancy and the current methods of prenatal screening in these patients. Invasive prenatal diagnosis will also be explored.

Adult↗
PubMed2005

Down syndrome screening in the first and second trimesters: what do the data show?

Recent advances in Down syndrome screening are providing women with additional options in how they are assessed for this condition. First trimester screening tests are at least as accurate as traditional second trimester testing and provide results earlier in a woman's pregnancy. Combining first and second trimester results increases the sensitivity and specificity of screening and reduce the number of women requiring invasive testing. This review summarizes and critiques the available data on Down syndrome screening and compares different testing algorithms. Meta-analyses of first trimester screening techniques are presented. Nuchal lucency measurements and other first trimester ultrasound markers, first trimester serum markers, and methods for combining these screens are addressed.

Chorionic Gonadotropin, beta Subunit, Human↗
PubMed2005

Education and quality review for nuchal translucency ultrasound.

First trimester nuchal translucency ultrasound has evolved from an ultrasound measurement used only in a research setting to a screening tool which is being offered to the general obstetric population. Studies of nuchal translucency suggest great variation in Down syndrome detection rates which may be secondary to significant differences in sonographic training and nuchal translucency image quality. Inaccurate screening has the potential to adversely impact patients. This paper will explore: (1) why quality review in nuchal translucency ultrasound is important, (2) methods of nuchal translucency quality assessment, (3) experience with quality review in the research setting, and (4) current strategies for quality assessment in patient care.

Female↗
PubMed2005

Additional benefits of first trimester screening.

The goal of first trimester screening for aneuploidy is to provide patients their risk assessment for fetal Down syndrome. Nonetheless, it has been noted that combined screening offers physicians and patients other important pregnancy information. For example, first trimester ultrasound results in accurate pregnancy dating and enables the early diagnosis of multiple gestations during the period when amnionicity and chorionicity is best discerned. It also detects a limited number of fetal anatomical abnormalities, affording patients time to make decisions regarding the management of their pregnancies. A cystic hygroma, one of the most powerful ultrasound markers for fetal aneuploidy, can be detected on first trimester ultrasound. An enlarged nuchal translucency may identify fetuses at risk for other adverse outcomes and for congenital heart defects. In addition, abnormal first trimester serum markers are associated with adverse pregnancy outcomes, and knowledge of these abnormalities may help with patient counseling and management.

Aneuploidy↗