Cross-trimester repeated measures testing for Down's syndrome screening: an assessment.

OBJECTIVES: To provide estimates and confidence intervals for the performance (detection and false-positive rates) of screening for Down's syndrome using repeated measures of biochemical markers from first and second trimester maternal serum samples taken from the same woman. DESIGN: Stored serum on Down's syndrome cases and controls was used to provide independent test data for the assessment of screening performance of published risk algorithms and for the development and testing of new risk assessment algorithms. SETTING: 15 screening centres across the USA, and at the North York General Hospital, Toronto, Canada. PARTICIPANTS: 78 women with pregnancy affected by Down's syndrome and 390 matched unaffected controls, with maternal blood samples obtained at 11-13 and 15-18 weeks' gestation, and women who received integrated prenatal screening at North York General Hospital at two time intervals: between 1 December 1999 and 31 October 2003, and between 1 October 2006 and 23 November 2007. INTERVENTIONS: Repeated measurements (first and second trimester) of maternal serum levels of human chorionic gonadotrophin (hCG), unconjugated estriol (uE3) and pregnancy-associated plasma protein A (PAPP-A) together with alpha-fetoprotein (AFP) in the second trimester. MAIN OUTCOME MEASURES: Detection and false-positive rates for screening with a threshold risk of 1 in 200 at term, and the detection rate achieved for a false-positive rate of 2%. RESULTS: Published distributional models for Down's syndrome were inconsistent with the test data. When these test data were classified using these models, screening performance deteriorated substantially through the addition of repeated measures. This contradicts the very optimistic results obtained from predictive modelling of performance. Simplified distributional assumptions showed some evidence of benefit from the use of repeated measures of PAPP-A but not for repeated measures of uE3 or hCG. Each of the two test data sets was used to create new parameter estimates against which screening test performance was assessed using the other data set. The results were equivocal but there was evidence suggesting improvement in screening performance through the use of repeated measures of PAPP-A when the first trimester sample was collected before 13 weeks' gestation. A Bayesian analysis of the combined data from the two test data sets showed that adding a second trimester repeated measurement of PAPP-A to the base test increased detection rates and reduced false-positive rates. The benefit decreased with increasing gestational age at the time of the first sample. There was no evidence of any benefit from repeated measures of hCG or uE3. CONCLUSIONS: If realised, a reduction of 1% in false-positive rate with no loss in detection rate would give important benefits in terms of health service provision and the large number of invasive tests avoided. The Bayesian analysis, which shows evidence of benefit, is based on strong distributional assumptions and should not be regarded as confirmatory. The evidence of potential benefit suggests the need for a prospective study of repeated measurements of PAPP-A with samples from early in the first trimester. A formal clinical effectiveness and cost-effectiveness analysis should be undertaken. This study has shown that the established modelling methodology for assessing screening performance may be optimistically biased and should be interpreted with caution

Cross-Country Individual Participant Analysis of 4.1 Million Singleton Births in 5 Countries with Very High Human Development Index...

Background: Preterm birth is the most common single cause of perinatal and infant mortality, affecting 15 million infants worldwide each year with global rates increasing. Understanding of risk factors remains poor, and preventive interventions have only limited benefit. Large differences exist in preterm birth rates across high income countries. We hypothesized that understanding the basis for these wide variations could lead to interventions that reduce preterm birth incidence in countries with high rates. We thus sought to assess the contributions of known risk factors for both spontaneous and provider-initiated preterm birth in selected high income countries, estimating also the potential impact of successful interventions due to advances in research, policy and public health, or clinical practice. Methods: We analyzed individual patient-level data on 4.1 million singleton pregnancies from four countries with very high human development index (Czech Republic, New Zealand, Slovenia, Sweden) and one comparator U.S. state (California) to determine the specific contribution (adjusting for confounding effects) of 21 factors. Both individual and population-attributable preterm birth risks were determined, as were contributors to cross-country differences. We also assessed the ability to predict preterm birth given various sets of known risk factors. Findings: Previous preterm birth and preeclampsia were the strongest individual risk factors of preterm birth in all datasets, with odds ratios of 4.6–6.0 and 2.8–5.7, respectively, for individual women having those characteristics. In contrast, on a population basis, nulliparity and male sex were the two risk factors with the highest impact on preterm birth rates, accounting for 25–50% and 11–16% of excess population attributable risk, respectively (p < 0.001). The importance of nulliparity and male sex on population attributable risk was driven by high prevalence despite low odds ratios for individual women. More than 65% of the total aggregated risk of preterm birth within each country lacks a plausible biologic explanation, and 63% of difference between countries cannot be explained with known factors; thus, research is necessary to elucidate the underlying mechanisms of preterm birth and, hence, therapeutic intervention. Surprisingly, variation in prevalence of known risk factors accounted for less than 35% of the difference in preterm birth rates between countries. Known risk factors had an area under the curve of less than 0.7 in ROC analysis of preterm birth prediction within countries. These data suggest that other influences, as yet unidentified, are involved in preterm birth. Further research into biological mechanisms is warranted. Conclusions: We have quantified the causes of variation in preterm birth rates among countries with very high human development index. The paucity of explicit and currently identified factors amenable to intervention illustrates the limited impact of changes possible through current clinical practice and policy interventions. Our research highlights the urgent need for research into underlying biological causes of preterm birth, which alone are likely to lead to innovative and efficacious interventions

Renal obstructive dysplasia: Ultrasound diagnosis and therapeutic implications

57 cases of renal obstructive dysplasia (defined as the abnormal development of nephronic and ductal structures due to in utero obstruction of the urinary tract) were evaluated in terms of sonographic findings, renal and other associated anomalies, and current status of the child. More than one-third of the cases had bilateral disease and although not uniformly fatal bilateral involvement was associated with significant morbidity and mortality. In 12 of the 33 cases with unilateral dysplasia there was an association with contralateral renal problems including ureteropelvic junction obstruction, vesicoureteral reflux and aplasia. Almost one-half of the cases had congenital anomalies, these included VACTERL association, congenital heart disease, cranial abnormalities and gastrointestinal malformations. Fifteen stillborns and 12 of the patients with bilateral involvement and four with unilateral involvement have died. Four patients are on dialysis (two with bilateral involvement and two with unilateral renal obstructive dysplasia). Only one-quarter are otherwise normal. More serious problems are reported in this mixed age population of patients with obstructive renal dysplasia than has been identified in previous studies. Management decisions of the fetus and child must be based on this new age-expanded population.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46696/1/247_2005_Article_BF02018623.pd

Consensus definition and diagnostic criteria for neonatal encephalopathy-study protocol for a real-time modified delphi study

BACKGROUND: 'Neonatal encephalopathy' (NE) describes a group of conditions in term infants presenting in the earliest days after birth with disturbed neurological function of cerebral origin. NE is aetiologically heterogenous; one cause is peripartum hypoxic ischaemia. Lack of uniformity in the terminology used to describe NE and its diagnostic criteria creates difficulty in the design and interpretation of research and complicates communication with families. The DEFINE study aims to use a modified Delphi approach to form a consensus definition for NE, and diagnostic criteria.METHODS: Directed by an international steering group, we will conduct a systematic review of the literature to assess the terminology used in trials of NE, and with their guidance perform an online Real-time Delphi survey to develop a consensus diagnosis and criteria for NE. A consensus meeting will be held to agree on the final terminology and criteria, and the outcome disseminated widely.DISCUSSION: A clear and consistent consensus-based definition of NE and criteria for its diagnosis, achieved by use of a modified Delphi technique, will enable more comparability of research results and improved communication among professionals and with families.IMPACT: The terms Neonatal Encephalopathy and Hypoxic Ischaemic Encephalopathy tend to be used interchangeably in the literature to describe a term newborn with signs of encephalopathy at birth. This creates difficulty in communication with families and carers, and between medical professionals and researchers, as well as creating difficulty with performance of research. The DEFINE project will use a Real-time Delphi approach to create a consensus definition for the term 'Neonatal Encephalopathy'. A definition formed by this consensus approach will be accepted and utilised by the neonatal community to improve research, outcomes, and parental experience.</p

Cross-Country Individual Participant Analysis of 4.1 Million Singleton Births in 5 Countries with Very High Human Development Index Confirms Known Associations but Provides No Biologic Explanation for 2/3 of All Preterm Births.

BACKGROUND: Preterm birth is the most common single cause of perinatal and infant mortality, affecting 15 million infants worldwide each year with global rates increasing. Understanding of risk factors remains poor, and preventive interventions have only limited benefit. Large differences exist in preterm birth rates across high income countries. We hypothesized that understanding the basis for these wide variations could lead to interventions that reduce preterm birth incidence in countries with high rates. We thus sought to assess the contributions of known risk factors for both spontaneous and provider-initiated preterm birth in selected high income countries, estimating also the potential impact of successful interventions due to advances in research, policy and public health, or clinical practice. METHODS: We analyzed individual patient-level data on 4.1 million singleton pregnancies from four countries with very high human development index (Czech Republic, New Zealand, Slovenia, Sweden) and one comparator U.S. state (California) to determine the specific contribution (adjusting for confounding effects) of 21 factors. Both individual and population-attributable preterm birth risks were determined, as were contributors to cross-country differences. We also assessed the ability to predict preterm birth given various sets of known risk factors. FINDINGS: Previous preterm birth and preeclampsia were the strongest individual risk factors of preterm birth in all datasets, with odds ratios of 4.6-6.0 and 2.8-5.7, respectively, for individual women having those characteristics. In contrast, on a population basis, nulliparity and male sex were the two risk factors with the highest impact on preterm birth rates, accounting for 25-50% and 11-16% of excess population attributable risk, respectively (p<0.001). The importance of nulliparity and male sex on population attributable risk was driven by high prevalence despite low odds ratios for individual women. More than 65% of the total aggregated risk of preterm birth within each country lacks a plausible biologic explanation, and 63% of difference between countries cannot be explained with known factors; thus, research is necessary to elucidate the underlying mechanisms of preterm birth and, hence, therapeutic intervention. Surprisingly, variation in prevalence of known risk factors accounted for less than 35% of the difference in preterm birth rates between countries. Known risk factors had an area under the curve of less than 0.7 in ROC analysis of preterm birth prediction within countries. These data suggest that other influences, as yet unidentified, are involved in preterm birth. Further research into biological mechanisms is warranted. CONCLUSIONS: We have quantified the causes of variation in preterm birth rates among countries with very high human development index. The paucity of explicit and currently identified factors amenable to intervention illustrates the limited impact of changes possible through current clinical practice and policy interventions. Our research highlights the urgent need for research into underlying biological causes of preterm birth, which alone are likely to lead to innovative and efficacious interventions

Further evidence of psychological factors underlying choice of elective cesarean delivery (ECD) by primigravidae

Objective: Requests for elective cesarean delivery (ECD) have increased in Iran. While some sociodemographic and fear-related factors have been linked with this choice, psychological factors such as self-esteem, stress, and health beliefs are under-researched. Methods: A total of 342 primigravidae (mean age = 25 years) completed questionnaires covering psychological dimensions such as self-esteem, perceived stress, marital relationship quality, perceived social support, and relevant health-related beliefs. Results: Of the sample, 214 (62.6%) chose to undergo ECD rather than vaginal delivery (VD). This choice was associated with lower self-esteem, greater perceived stress, belief in higher susceptibility to problematic birth and barriers to an easy birth, along with lower perceived severity of ECD, fewer perceived benefits from VD, lower self-efficacy and a lower feeling of preparedness. No differences were found for marital relationship quality or perceived social support. Conclusions: The pattern suggests that various psychological factors such as self-esteem, self-efficacy, and perceived stress underpin the decision by primigravidae to have an ECD

Down syndrome serum screening also identifies an increased risk for multicystic dysplastic kidney, two-vessel cord, and hydrocele

The FASTER trial compared 1st and 2nd trimester screening methods for aneuploidy. We examined relationships between maternal serum markers and common congenital anomalies in the pediatric outcome data set of 36,837 subjects

Preconceptional Folate Supplementation and the Risk of Spontaneous Preterm Birth: A Cohort Study

In an analysis of a cohort of pregnant women, Radek Bukowski and colleagues describe an association between taking folic acid supplements and a reduction in the risk of preterm birth

Mitral valve surgery for mitral regurgitation caused by Libman-Sacks endocarditis: a report of four cases and a systematic review of the literature

Libman-Sacks endocarditis of the mitral valve was first described by Libman and Sacks in 1924. Currently, the sterile verrucous vegetative lesions seen in Libman-Sacks endocarditis are regarded as a cardiac manifestation of both systemic lupus erythematosus (SLE) and the antiphospholipid syndrome (APS). Although typically mild and asymptomatic, complications of Libman-Sacks endocarditis may include superimposed bacterial endocarditis, thromboembolic events, and severe valvular regurgitation and/or stenosis requiring surgery. In this study we report two cases of mitral valve repair and two cases of mitral valve replacement for mitral regurgitation (MR) caused by Libman-Sacks endocarditis. In addition, we provide a systematic review of the English literature on mitral valve surgery for MR caused by Libman-Sacks endocarditis. This report shows that mitral valve repair is feasible and effective in young patients with relatively stable SLE and/or APS and only localized mitral valve abnormalities caused by Libman-Sacks endocarditis. Both clinical and echocardiographic follow-up after repair show excellent mid- and long-term results

Defining gestational thyroid dysfunction through modified non-pregnancy reference intervals: an individual participant meta-analysis

Background: Establishing local trimester-specific reference intervals for gestational TSH and FT4 is often not feasible, necessitating alternative strategies. We aimed to systematically quantify the diagnostic performance of standardized modifications of center-specific non-pregnancy reference intervals as compared to trimester-specific reference intervals. Methods: We included prospective cohorts participating in the Consortium on Thyroid and Pregnancy. After relevant exclusions, reference intervals were calculated per cohort in thyroperoxidase antibody-negative women. Modifications to the non-pregnancy reference intervals included an absolute modification (per 0.1 mU/L TSH or 1 pmol/L FT4), relative modification (in steps of 5%) and fixed limits (upper TSH limit between 3.0 to 4.5 mU/L and lower FT4 limit 5-15 pmol/L). We compared (sub)clinical hypothyroidism prevalence, sensitivity and positive predictive value (PPV) of aforementioned methodologies with population-based trimester-specific reference intervals. Results: The final study population comprised 52,496 participants in 18 cohorts. Optimal modifications of standard reference intervals to diagnose gestational overt hypothyroidism were -5% for the upper limit of TSH and +5% for the lower limit of FT4 (sensitivity 0.70, confidence interval [CI] 0.47-0.86; PPV 0.64, CI 0.54-0.74). For subclinical hypothyroidism, these were -20% for the upper limit of TSH and -15% for the lower limit of FT4 (sensitivity 0.91, CI 0.67-0.98; PPV 0.71, CI 0.58-0.80). Absolute and fixed modifications yielded similar results. Confidence intervals were wide, limiting generalizability. Conclusion: We could not identify modifications of non-pregnancy TSH and FT4 reference intervals that would enable centers to adequately approximate trimester-specific reference intervals. Future efforts should be turned towards studying the meaningfulness of trimester-specific reference intervals and risk-based decision limits