Birth Prevalence (birth + prevalence)

Distribution by Scientific Domains

Selected Abstracts

,-thalassaemia carrier detection by ELISA: A simple screening strategy for developing countries

M. Shyla Ravindran
Abstract The frequency of ,-thalassaemia in India ranges from 3.5% to 15% in the general population and of the 100,000 children born with thalassaemia major in the world, 10,000 are in India alone. Affected children do not die immediately, but treatment by regular transfusion is costly and leads to iron overload and death. Therefore, health services in lower-economic countries can sustain patients only if the numbers can be limited. Detecting carrier couples by simple blood test can prevent thalassaemia and at-risk couples can be identified and informed of their genetic risk before having children. A prevention programme including population screening, counselling, and prenatal diagnosis will markedly reduce the birth prevalence of affected individuals. Hemoglobin A2 (HbA2) measurement in human hemolysates has great significance, since its level can indicate ,-thalassaemia carrier status in otherwise healthy individuals. We have developed a rapid, simple, and inexpensive enzyme linked immunosorbent assay (ELISA) for the quantitation of HbA2, which can be used in carrier screening programmes in developing countries like India. In a limited trial for ,-thalassaemia carrier screening, the results obtained with ELISAs were compared with those obtained with the microcolumn chromatography method (r=0.89). J. Clin. Lab. Anal. 19:22,25, 2005. © 2005 Wiley-Liss, Inc. [source]

Non-genetic risk factors for holoprosencephaly,,§

Candice Y. Johnson¶
Abstract Holoprosencephaly (HPE) is a congenital defect of the brain characterized by incomplete cleavage of the embryonic forebrain into left and right hemispheres. Although a substantial proportion of cases of HPE can be attributed to genetic abnormalities, the etiology in many cases remains unknown, with non-genetic risk factors believed to be important contributors. Due to the low birth prevalence of this defect, it has proven difficult to conduct studies of sufficient size to identify risk factors with certainty. This article provides a summary of non-genetic risk factors for HPE that have been investigated in case reports and case series, animal studies, and epidemiologic studies, including maternal illnesses, therapeutic and non-therapeutic exposures, nutritional factors, and sociodemographic factors. The article also highlights challenges in study design and further areas for research to better understand the etiology of HPE. Published 2010 Wiley-Liss, Inc. [source]

Maternal age-specific fetal loss rates in Down syndrome pregnancies

George M. Savva
Abstract Objectives Pregnancies affected by Down syndrome (DS) have a greater risk of spontaneous fetal loss than those that are unaffected. In this article, we investigate the relationship between maternal age and the risk of spontaneous fetal loss in DS pregnancies. Methods Fetal loss at different maternal ages were estimated by survival analysis using follow-up of 5177 prenatally diagnosed cases. The maternal age effect on loss rate was subsequently confirmed by a re-analysis of published comparisons of the maternal age-specific prevalence of DS at different gestational ages. Results The average fetal loss rate between the time of chorionic villus sampling (CVS) and term was 32% (95% CI: 26,38), increasing from 23% (95% CI: 16,31) for women aged 25 to 44% (33,56) for women aged 45. The average fetal loss rate between the time of amniocentesis and term was 25% (21,31), increasing from 19% (14,27) to 33% (26,45) across the same age range. Conclusion The fetal loss rate in DS pregnancies increases with maternal age, and this has consequences when estimating the live birth prevalence of DS in the presence of prenatal diagnosis and termination, and when assessing the performance of prenatal screening techniques. Copyright © 2006 John Wiley & Sons, Ltd. [source]

Accuracy of trisomy 18 screening using the second-trimester triple test

Chris Meier
Abstract Objective To assess the accuracy of the calculated risk for trisomy 18 assigned to individual women screened with the second-trimester triple test. Methods The study was based on 382 598 women screened in the Ontario Maternal Serum Screening Programme between October 1993 and September 2000. Of the women screened, 111 cases of trisomy 18 were identified. Originally, 92 874 women were screened using a risk cut-off level method. Estimated risks of trisomy 18 were calculated by applying published population parameters for the remaining women screened using a fixed analyte cut-off method. Women were ranked according to their individual risk for trisomy 18 syndrome in decreasing order and divided into 12 groups. The mean calculated risks of having an affected pregnancy at term for each group were compared with the birth prevalence of the corresponding group after allowing for spontaneous fetal losses. Results Agreement between the mean calculated risks and the observed prevalence was seen across the entire risk range, although women identified as having high-risk pregnancies had an actual prevalence that was somewhat lower than that estimated by the screen. Conclusion The calculated risk for trisomy 18 syndrome assigned to the individual woman on the basis of the risk cut-off method accurately reflects their risk of having a term trisomy 18 syndrome pregnancy. Copyright © 2003 John Wiley & Sons, Ltd. [source]

Prevalence of neural tube defects in Australia prior to mandatory fortification of bread-making flour with folic acid

Samanthi Abeywardana
Abstract Objective: To establish baseline prevalence of neural tube defects (NTDs) prior to mandatory folic acid fortification in Australia. Method: Retrospective population based study. Data from the Australian Congenital Anomalies Monitoring System, for 1998,2005 were used to calculate birth prevalence including live/stillbirths of at least 20 weeks gestation or 400 g birthweight. Total prevalence and trends of NTD including terminations of pregnancy (TOPs) before 20 weeks were established using data from South Australia, Victoria and Western Australia because of the incomplete ascertainment in other states. Results: The birth prevalence of NTDs from 1998,2005, was 5/10,000 births. The total prevalence including TOPs was 13/10,000 births. A 26% declining trend in total prevalence was seen from 1992,2005, but the main decline occurred prior to 1998. Women who were Indigenous, socially disadvantaged, young, living in remote areas and had multiple gestations were more likely to give birth to babies with NTDs. Conclusion: The prevalence of NTD has been stable since 1998. Reporting of the birth prevalence alone underestimates the actual prevalence of NTD. Implications: From a public health perspective, future monitoring of NTD following implementation of fortification of bread-making flour with folic acid should include a mixed methods approach; reporting birth prevalence on national data and total prevalence on tri-state data. [source]

Extremely high prevalence of neural tube defects in a 4-county area in Shanxi Province, China

Zhiwen Li
Abstract BACKGROUND In the past, northern China's Shanxi Province has reported the highest incidence of neural tube defects (NTDs) in the world. However, little is known about the epidemiology of NTDs in this area in recent years. METHODS Data were collected from a population-based birth defects surveillance system in 4 counties that captures information on all live births, stillbirths of at least 20 weeks' gestation, and pregnancy terminations at any gestational age resulting from prenatal diagnosis of a birth defect. We also surveyed mothers of NTD case patients to determine their use of folic acid before and during early pregnancy. RESULTS During 2003, 160 NTD cases were identified among 11,534 births (NTD birth prevalence = 138.7/10,000 births). The rates of anencephaly, spina bifida and encephalocele were 65.9, 58.1, and 14.7 per 10,000, respectively, and a female predominance was observed among anencephaly cases (male-to-female relative risk [RR], 0.49; 95% confidence interval [CI], 0.30,0.79), but not among spina bifida (RR, 0.90; 95% CI, 0.55,1.45) and encephalocele (RR, 1.03; 95% CI, 0.40,2.69) cases. The percentages of pregnancy termination following prenatal diagnosis of anencephaly, spina bifida, and encephalocele were 50%, 41.8%, and 35.3%, respectively. NTD birth prevalence tended to be higher among mothers aged <20 or ,30 years (P = .06) and was markedly associated with lower levels of maternal education (P < .001). Among 143 NTD mothers, only 6 (4.2%) used folic acid supplements during the periconceptional period. CONCLUSIONS The NTD birth prevalence rate in the study area is among the highest worldwide. Folic acid deficiency may be one important risk factor. Birth Defects Research (Part A), 2006. © 2006 Wiley-Liss, Inc. [source]

Prenatal diagnosis, pregnancy terminations and prevalence of Down syndrome in Atlanta,

Csaba Siffel
Abstract BACKGROUND The impact of prenatal diagnosis on the live birth prevalence of Down syndrome (trisomy 21) has been described. This study examines the prevalence of Down syndrome before (1990,1993) and after inclusion of prenatally diagnosed cases (1994,1999) in a population-based registry of birth defects in metropolitan Atlanta. METHODS We identified infants and spontaneous fetal deaths with Down syndrome (n = 387), and pregnancies electively terminated after a prenatal diagnosis of Down syndrome (n = 139) from 1990 to 1999 among residents of metropolitan Atlanta from a population-based registry of birth defects, the Metropolitan Atlanta Congenital Defects Program (MACDP). Only diagnoses of full trisomy 21 were included. Denominator information on live births was derived from State of Georgia birth certificate data. We compared the prevalence of Down syndrome by calendar period (1990,1993, 1994,1999), maternal age (<35 years, 35+ years), and race/ethnicity (White, Black, other), using chi-square and Fisher's exact tests. RESULTS During the period when case ascertainment was based only on hospitals (1990,1993), the prevalence of Down syndrome was 8.4 per 10,000 live births when pregnancy terminations were excluded and 8.8 per 10,000 when terminations were included. When case ascertainment also included perinatal offices (1994,1999), the prevalence of Down syndrome was 10.1 per 10,000 when terminations were excluded and 15.3 when terminations were included. During 1990,1993, the prevalence of Down syndrome was 24.7 per 10,000 among offspring to women 35+ years of age compared to 6.8 per 10,000 among offspring to women <35 years of age (rate ratio [RR] = 3.65, 95% confidence interval [CI] = 2.53,5.28). During 1994,1999, the prevalence of Down syndrome was 55.3 per 10,000 among offspring to women 35+ years compared to 8.5 per 10,000 among offspring to women <35 years (RR = 6.55, 95% CI = 5.36,7.99). There was no statistically significant variation in the prevalence of Down syndrome by race/ethnicity within maternal age and period of birth strata. During 1994,1999, the proportion of cases that were electively terminated was greater for women 35+ years compared to women <35 years (RR = 5.10, 95% CI = 3.14,8.28), and lower for Blacks compared to Whites among women 35+ years of age (RR = 0.33, 95% CI = 0.16,0.66). CONCLUSIONS In recent years, perinatal offices have become an important source of cases of Down syndrome for MACDP, contributing at least 34% of cases among pregnancies in women 35+ years of age. Variation in the prevalence of Down syndrome by race/ethnicity, before or after inclusion of cases ascertained from perinatal offices, was not statistically significant. Among Down syndrome pregnancies in mothers 35+ years we found a lower proportion of elective termination among Black women compared to White women. We suggest that future reports on the prevalence of Down syndrome by race/ethnicity take into account possible variations in the frequency of prenatal diagnosis or elective termination by race/ethnicity. Birth Defects Research (Part A) 70565,571, 2004. Published 2004 Wiley-Liss, Inc. [source]

Molecular epidemiology of hypospadias: Review of genetic and environmental risk factors

Jeanne M. Manson
Hypospadias is one of the most common congenital anomalies in the United States, occurring in approximately 1 in 125 live male births. It is characterized by altered development of the urethra, foreskin, and ventral surface of the penis. In this review, the embryology, epidemiology, risk factors, genetic predisposition, and likely candidate genes for hypospadias are described. Recent reports have identified increases in the birth prevalence of mild and severe forms of hypospadias in the United States from the 1960s to the present. Studies in consanguineous families and small case series have identified allelic variants in genes controlling androgen action and metabolism that cause hypospadias, but the relevance of these findings to the general population is unknown. Concern has also focused on whether exposure to endocrine disrupting chemicals (EDC) with antiandrogenic activity is the cause of this increase. Hypospadias is believed to have a multifactorial etiology in which allelic variants in genes controlling androgen action and metabolism predispose individuals to develop this condition. When genetic susceptibility is combined with exposure to antiandrogenic agents, a threshold is surpassed, resulting in the manifestation of this birth defect. A clear role for exposure to antiandrogenic environmental chemicals has yet to be established in the etiology of hypospadias, although results from laboratory animal models indicate that a number of environmental chemicals could be implicated. Molecular epidemiology studies that simultaneously examine the roles of allelic variants in genes controlling androgen action and metabolism, and environmental exposures are needed to elucidate the risk factors for these anomalies and the causes of the increased rate of hypospadias. Birth Defects Research (Part A), 2003. © 2003 Wiley-Liss, Inc. [source]

Completeness of state administrative databases for surveillance of congenital heart disease

Christine E. Cronk
Abstract BACKGROUND Tracking birth prevalence of cardiac defects is essential to determining time and space clusters, and identifying potential associated factors. Resource limitations on state birth defects surveillance programs sometimes require that databases already available be used for ascertaining such defects. This study evaluated the data quality of state administrative databases for ascertaining congenital heart defects (CHD) and specific diagnoses of CHD. METHODS Children's Hospital of Wisconsin (CHW) medical records for infants born 1997,1999 and treated for CHD (n = 373) were abstracted and each case assigned CHD diagnoses based on definitive diagnostic reports (echocardiograms, catheterizations, surgical or autopsy reports). These data were linked to state birth and death records, and birth and postnatal (<1 year of age) hospital discharge summaries at the Wisconsin Bureau of Health Information (WBHI). Presence of any code/checkbox indicating CHD (generic CHD) and exact matches to abstracted diagnoses were evaluated. RESULTS Fifty-eight percent of cases with generic CHD were identified by state databases. Postnatal hospital discharge summaries identified 48%, birth hospital discharge summaries 27%, birth certificates 9% and death records 4% of these cases. Exact matches were found for 52% of 633 specific diagnoses. Postnatal hospital discharge summaries provided most matches. CONCLUSION State databases identified 60% of generic CHD and exactly matched about half of specific CHD diagnoses. The postnatal hospital discharge summaries performed best in both in identifying generic CHD and matching specific CHD diagnoses. Vital records had limited value in ascertaining CHD. Birth Defects Research (Part A) 67:597,603, 2003. © 2003 Wiley-Liss, Inc. [source]

Follow up and evaluation of the Victorian first-trimester combined screening programme for Down syndrome and trisomy 18

AM Jaques
Objective, The objective of this study was to follow up and evaluate the statewide first-trimester combined screening programme for Down syndrome and trisomy 18 at Genetic Health Services Victoria, Australia. Design, Retrospective population cohort. Setting, Maternal Serum Screening Laboratory records. Sample, All women screened between February 2000 and June 2002 (16 153 pregnancies). Methods, Screening results were matched to Victorian perinatal and birth defect data via record linkage, with an ascertainment of 96.8% of pregnancy outcomes. Manual follow up with health professionals increased ascertainment to more than 99%. Main outcome measures, Fetal Down syndrome or trisomy 18, and combined screen results, to calculate test characteristics. Results, Using a risk threshold of 1 in 300 at time of ultrasound, the sensitivities for standard first-trimester combined screening and augmented 13-week combined screening for Down syndrome were 87.3 and 90.5% and the false-positive rates (FPR) were 4.1 and 3.9%, respectively. The sensitivity for trisomy 18 was 66.7% (10/15, 95% CI 42.8,90.5%) with a 0.4% FPR and 15.2% positive predictive value (1 in 250 risk threshold). Conclusions, The combined use of record linkage and manual follow-up techniques was effective in ascertaining more than 99% of pregnancy outcomes for calculations of accurate test characteristics of the combined screen. The sensitivity for Down syndrome at Genetic Health is comparable to similar populations. However, the sensitivity for trisomy 18 is lower than that elsewhere, which may reflect the overall low birth prevalence of trisomy 18 and associated small numbers in this particular cohort. [source]

Congenital cytomegalovirus infection: the impact of cerebral cortical malformations

M-L Engman
ABSTRACT Aim:, Cytomegalovirus has been suggested to have a teratogenous influence during the migration of neural cells from the ventricular zones to the cortex during the gestational period. The aim of this study was to investigate the prevalence of congenital cytomegalovirus infections in a cohort of children with neurological disability and cerebral cortical malformations recognized by neuroimaging. Methods:, Twenty-six children with neurological disability and cerebral cortical malformations were investigated retrospectively for congenital cytomegalovirus infection by analysing the dried blood spot samples for cytomegalovirus deoxynucleic acid using qualitative polymerase chain reaction. Results:, CMV DNA in the dried blood spot samples was found in four out of 26 children. Two of these four had severe disabilities with mental retardation, autism, spastic cerebral palsy, epilepsy and deafness. A third child had epilepsy and unilateral cerebral palsy, while the fourth had a mild motor coordination dysfunction and hearing deficit. Conclusion:, In our study, the number of congenital cytomegalovirus infections in children with cerebral cortical malformations was higher (4/26) than expected with reference to the birth prevalence (0.2,0.5%) of congenital cytomegalovirus infection in Sweden. We thus conclude that congenital cytomegalovirus infection should be considered in children with cortical malformations of unknown origin. [source]

Primary microcephaly in Hungary: epidemiology and clinical features

Nóra Szabó
Abstract Aim:, To describe the population-based epidemiological characteristics and clinical features of primary microcephaly in Hungary. Methods:, A retrospective survey of patients born with microcephaly in a region (Dél-Alföld , South Great Plain) in Hungary between July 1, 1992 and June 30, 2006 was performed. Patients with microcephaly and without any environmental or obstetric risk factors and/or dysmorphism (primary microcephaly) were included in the study. The birth prevalence of primary microcephaly per 10 000 live births was calculated. Results:, Ten patients (8 girls and 2 boys) were found with primary microcephaly among 185 486 live births, which corresponds to a birth prevalence of 0.54 per 10 000 live births (95% confidence interval: 0.20,0.87). Developmental delay and intellectual disability were the main clinical features. Dyskinesia was seen in one and epilepsy was diagnosed in two patients. The MRI revealed simplified gyral pattern in all patients. Conclusion:, Primary microcephaly is a very rare brain malformation, although the birth prevalence found in this survey is slightly higher than the few figures published earlier. As more and more genes and mutations responsible for primary microcephaly are discovered, the ascertainment of these rare cases is mandatory to provide the parents with genetic counselling. [source]

Foetal and congenital talipes: interventions and outcome

Ravi Swamy
Abstract Aim: Talipes is a congenital anomaly that can be corrected conservatively or surgically. Despite advances in management, a proportion of pregnancies still result in termination. We therefore aimed to establish the birth prevalence, interventions and outcome of talipes in our population. Methods: Cases with foetal talipes were identified from the ultrasound register at the James Cook University Hospital between 1990 and 2006. Infants with congenital talipes between 1998 and 2006 were identified from the physiotherapy database. Management details were obtained from case records. Results: A total of 46 cases with foetal talipes were identified among 75 933 pregnancies. Of the 34 live-born infants, 24 (70.5%) required surgery to correct the talipes. Congenital talipes was found in 69 infants, giving a birth prevalence of 2 per 1000 live births. Sixteen (72.7%) infants with an antenatal diagnosis required surgical correction. Infants with an antenatal diagnosis were at an increased risk of requiring surgery (relative risk [RR]= 1.6). Conclusion: Surgical management was required in more than two-thirds of babies with foetal talipes. Conservative management was successful in the majority of the babies without an antenatal diagnosis. Infants with an antenatal diagnosis are 1.6 times as likely to need surgical correction as infants without an antenatal diagnosis. [source]

Congenital heart disease in 111 225 births in Belgium: birth prevalence, treatment and survival in the 21st century

Philip Moons
Abstract Aim: To investigate the birth prevalence, treatment modalities and short-term survival of children with congenital heart disease who were born in 2002. Methods: We undertook a retrospective review of medical records of all patients who were born in 2002, and were diagnosed, treated and/or followed-up in one of the seven-paediatric cardiology programmes in Belgium. Results: In 111 225 births, 921 children with congenital heart disease were detected, yielding a birth prevalence of 8.3 per 1000. The most frequently occurring conditions were ventricular septal defects (VSDs) (33%), ostium secundum atrial septal defects (18%) and pulmonary valve abnormalities (10%). Thirty-nine percent of the children either had a cardiosurgical operation or catheter intervention. In this study, 4% of the children died. The actuarial survival at 6 months and 1 year of age was 97% and 96%, respectively and remained stable after then. Compared to other heart defects, mortality was higher in univentricular physiology, pulmonary atresia with VSD, left ventricle outflow obstruction and tetralogy of Fallot. Conclusion: Survival of congenital heart disease is excellent and continued to improve in the early 21st century. New therapeutic options are increasingly used. This study provides baseline data for the longitudinal follow-up of this cohort. [source]

Folic acid,containing supplement consumption during pregnancy and risk for oral clefts: A meta-analysis,

Rachel L. Badovinac
Abstract BACKGROUND: There is equivocal evidence in the published literature that folic acid supplementation during pregnancy may protect against the common congenital anomalies cleft lip with or without cleft palate (CLP) and cleft palate alone (CP). We undertook this meta-analysis to test the hypothesis that nonsyndromic oral cleft birth prevalences are different for those whose mothers took folic acid,containing supplements and for those whose mothers did not. METHODS: Human studies published in English were identified through MEDLINE, bibliography reviews, and contacting experts in the field. Within strata of prospective and case-control studies, CLP, CP, and all clefts, respectively, were analyzed using either a fixed or random effects model, as appropriate. We assessed for publication bias using Begg and Mazumdar's rank correlation and Egger's regression-based tests. RESULTS: Five prospective studies were analyzed, yielding combined relative risks of 0.51 (95% CI: 0.32, 0.95) for CLP, 1.19 (95% CI: 0.43, 3.28) for CP, and 0.55 (95% CI: 0.32, 0.95) for all clefts. Twelve case-control studies were assessed, which resulted in combined relative risks of 0.77 (95% CI: 0.65, 0.90) for CLP, 0.80 (95% CI: 0.69, 0.93) for CP, and 0.78 (95% CI: 0.71, 0.85) for all clefts. CONCLUSIONS: In aggregate, our results support the hypothesis of a protective effect of folic acid,containing supplement intake during pregnancy on the risk for oral clefts, although this conclusion is tempered by the potential for bias and uncontrolled confounding. Birth Defects Research (Part A), 2007. © 2006 Wiley-Liss, Inc. [source]