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Ultrasound in Obstetrics & Gynecology :... Aug 2014The aim of this systematic review was to explore the relationship between crown-rump length (CRL) discordance detected at 11-14 weeks of gestation and adverse outcome in... (Meta-Analysis)
Meta-Analysis Review
OBJECTIVE
The aim of this systematic review was to explore the relationship between crown-rump length (CRL) discordance detected at 11-14 weeks of gestation and adverse outcome in twin pregnancy and to assess its predictive accuracy.
METHODS
A protocol designed a priori following MOOSE guidelines and recommended for systematic review and meta-analysis was used. The outcomes observed were: total fetal and perinatal loss, fetal loss at <24 weeks, fetal loss at ≥ 24 weeks, birth-weight (BW) discordance, preterm delivery (PTD) at < 34 weeks and fetal anomalies. The analysis was performed for all twins and for dichorionic (DC) and monochorionic (MC) twins separately.
RESULTS
A total of 2008 articles were identified and 17 studies were included in the systematic review. Twin pregnancies with CRL discordance ≥ 10% were at significantly higher risk of perinatal loss (RR, 2.80; 95% CI, 1.25-6.27; P = 0.012), fetal loss at ≥ 24 weeks (RR, 4.07; 95% CI, 1.47-11.23; P = 0.006), BW discordance (RR, 2.24; 95% CI, 1.89-2.64; P < 0.001) and PTD at < 34 weeks (RR, 1.49; 95% CI, 1.23-1.80; P < 0.001) but not of fetal loss at < 24 weeks (P = 0.130). A meta-analysis of fetal anomalies was not possible because fewer than two studies explored this outcome. However, when used alone to screen for adverse pregnancy outcome, the predictive accuracy of CRL discordance was low for each of the outcomes explored.
CONCLUSION
CRL discordance is associated with an increased risk of adverse pregnancy outcome. However, the accuracy of CRL discordance in predicting adverse outcome is poor and thus limits its routine use in clinical practice.
Topics: Birth Weight; Crown-Rump Length; Female; Fetus; Humans; Infant, Newborn; Pregnancy; Pregnancy Outcome; Pregnancy, Twin; Twins, Dizygotic; Twins, Monozygotic; Ultrasonography, Prenatal
PubMed: 24585501
DOI: 10.1002/uog.13335 -
Clinical Dysmorphology Oct 2012The VATER/VACTERL association is typically defined by the presence of at least three of the following congenital malformations: vertebral anomalies, anal atresia,... (Review)
Review
The VATER/VACTERL association is typically defined by the presence of at least three of the following congenital malformations: vertebral anomalies, anal atresia, cardiac malformations, tracheo-esophageal fistula, renal anomalies, and limb abnormalities. The identification of 14 twin pairs with an initial diagnosis of VATER/VACTERL association at our clinical centers led to the performance of a classical twin study. This involved a thorough evaluation of these 14 twin pairs and a further 55 twin pairs identified from a systematic review of the literature. The zygosity, concordance, and malformation status of all 69 twin pairs were evaluated. Twenty-four twin pairs fulfilled the criteria for inclusion in a comparison of the concordance rates between monozygous (MZ) and dizygous (DZ) twin pairs. The pairwise concordance rates were 15% [95% confidence interval (CI) 4-42%] for MZ and 18% (95% CI 5-48%) for DZ twin pairs (P=0.53). The probandwise concordance rates were 27% (95% CI 11-52%) for MZ and 31% (95% CI 13-58%) for DZ twin pairs (P=0.40). Although based on a limited number of twin pairs, the findings of the present study are consistent with the low number of familial cases reported to date, and suggest that the role of inherited genetic factors in the majority of VATER/VACTERL cases is limited.
Topics: Anus, Imperforate; Diseases in Twins; Esophagus; Heart Defects, Congenital; Humans; Radius; Spine; Trachea; Twins, Dizygotic; Twins, Monozygotic
PubMed: 22895008
DOI: 10.1097/MCD.0b013e328358243c -
PloS One 2011Acute rheumatic fever is considered to be a heritable condition, but the magnitude of the genetic effect is unknown. The objective of this study was to conduct a... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Acute rheumatic fever is considered to be a heritable condition, but the magnitude of the genetic effect is unknown. The objective of this study was to conduct a systematic review and meta-analysis of twin studies of concordance of acute rheumatic fever in order to derive quantitative estimates of the size of the genetic effect.
METHODS
We searched PubMed/MEDLINE, ISI Web of Science, EMBASE, and Google Scholar from their inception to 31 January 2011, and bibliographies of retrieved articles, for twin studies of the concordance for acute rheumatic fever or rheumatic heart disease in monozygotic versus dizygotic twins that used accepted diagnostic criteria for acute rheumatic fever and zygosity without age, gender or language restrictions. Twin similarity was measured by probandwise concordance rate and odds ratio (OR), and aggregate probandwise concordance risk was calculated by combining raw data from each study. ORs from separate studies were combined by random-effects meta-analysis to evaluate association between zygosity status and concordance. Heritability was estimated by fitting a variance components model to the data.
RESULTS
435 twin pairs from six independent studies met the inclusion criteria. The pooled probandwise concordance risk for acute rheumatic fever was 44% in monozygotic twins and 12% in dizygotic twins, and the association between zygosity and concordance was strong (OR 6.39; 95% confidence interval, 3.39 to 12.06; P<0.001), with no significant study heterogeneity (P = 0.768). The estimated heritability across all the studies was 60%.
CONCLUSIONS
Acute rheumatic fever is an autoimmune disorder with a high heritability. The discovery of all genetic susceptibility loci through whole genome scanning may provide a clinically useful genetic risk prediction tool for acute rheumatic fever and its sequel, rheumatic heart disease.
Topics: Genetic Predisposition to Disease; Humans; Rheumatic Fever; Twin Studies as Topic; Twins, Dizygotic; Twins, Monozygotic
PubMed: 21980428
DOI: 10.1371/journal.pone.0025326