Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “birth defect”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 55 records · Page 3Linked to original sources
PubMed2001

The National Birth Defects Prevention Study.

The National Birth Defects Prevention Study was designed to identify infants with major birth defects and evaluate genetic and environmental factors associated with the occurrence of birth defects. The ongoing case-control study covers an annual birth population of 482,000 and includes cases identified from birth defect surveillance registries in eight states. Infants used as controls are randomly selected from birth certificates or birth hospital records. Mothers of case and control infants are interviewed and parents are asked to collect buccal cells from themselves and their infants for DNA testing. Information gathered from the interviews and the DNA specimens will be used to study independent genetic and environmental factors and gene-environment interactions for a broad range of birth defects. As of December 2000, 7,470 cases and 3,821 controls had been ascertained in the eight states. Interviews had been completed with 70% of the eligible case and control mothers, buccal cell collection had begun in all of the study sites, and researchers were developing analysis plans for the compiled data. This study is the largest and broadest collaborative effort ever conducted among the nation's leading birth defect researchers. The unprecedented statistical power that will result from this study will enable scientists to study the epidemiology of some rare birth defects for the first time. The compiled interview data and banked DNA of approximately 35 categories of birth defects will facilitate future research as new hypotheses and improved technologies emerge.

Case-Control Studies↗
PubMed1999

Prenatal screening and the reduction of birth defects in populations.

OBJECTIVES: Birth defects occur in populations in 3-5% of births. This paper assesses whether population-wide screening programmes for pregnant women would be likely to result in major decreases in the prevalence of birth defects. METHOD: Relevant literature on this question is reviewed and synthesized. RESULTS: Given certain assumptions, a decrease from 3-5 to 2-4% in the prevalence of defects at birth may be possible. The resources required to put in place an appropriately delivered programme to achieve this are substantial. CONCLUSIONS: As well as the potential benefit of a decrease, there are opportunity costs, and potential serious harms. Unless undertaken in a carefully planned and monitored way, a population-based birth defects reduction programme is likely to bring harm and anxiety rather than benefit.

Journal Article↗
PubMedDate not supplied

Birth defects: from molecules to mechanisms.

Birth defects remain a major clinical problem and, although much progress has been made in prenatal diagnosis, few measures are available for primary prevention. This is due, in large part, to our rudimentary understanding of the embryonic mechanisms of birth defects. Until recently it was customary to concentrate on defining teratogenic factors that may be active in humans. Now, with the rapid expansion in molecular biological technology, it has become possible to identify and isolate the genes that determine heritable predisposition to birth defects. The most productive strategy appears to be the genetic analysis of animal, principally mouse, models in which particular classes of birth defects develop owing to known genetic mutations. Gene targeting techniques allow mutations to be induced in previously cloned genes, permitting their potential as birth defect-inducing genes to be evaluated. Gene cloning alone, however, cannot reveal the entire pathogenetic sequence for any birth defect, since the most downstream events can be elucidated only by experimental embryological analysis. Culture methods are now available in which intact mouse and rat embryos undergo normal development for limited periods in vitro. Studies of this type have revealed several steps in the embryonic development of genetically determined spina bifida. The combination of gene centered and embryo centred research promises to advance our understanding of the pathogenesis of major birth defects.

Animals↗
PubMedDate not supplied

Computational systems analysis of developmental toxicity: design, development and implementation of a Birth Defects Systems Manager (BDSM).

Birth defects and developmental disabilities remain an important public health issue worldwide. With the availability of genomic sequences from a growing number of human and model organisms and the rapid expansion of the public repositories holding large-scale gene expression datasets, a computational systems analysis of developmental toxicology can incorporate this vast digital information toward the realization of predictive models for complex disease. Here we describe the initial design, development and implementation of a Birth Defects Systems Manager (BDSM). The project was motivated by the need for a computational-bioinformatics infrastructure to manage vast digital information from functional genomics and for a new knowledge environment specifically engineered for the analysis of developmental processes and toxicities. Proof-of-concept tested BDSM using meta-analysis of gene expression data collected from different laboratories, technology platforms, and study models. The composite dataset incorporated 232 microarray comparisons of RNA samples by single or dual microarray platforms, cDNA or oligonucleotide based probes, and human or mouse sequence information. Preliminary results identified system-level features in the embryonic transcriptome as it reacted to various developmental-teratological stimuli. BDSM is open access through the worldwide web (http://systemsanalysis.louisville.edu/) and can be integrated with other bioinformatics tools and resources to advance the pace of discovery in birth defects research.

Animals↗
PubMedDate not supplied

Exploratory spatial analysis of birth defect rates in an urban population.

Are birth defect rates unusually high in particular urban localities? The answer requires that the birth defect rate for which 'significance' is claimed be adjusted for the variable population sizes of each area for which the rate is computed and for the spatial dependence of rates based on shared observations between neighboring areas. By address-matching birth and birth defect records to a digital road map, we are able to compute local birth defect rates at regular grid locations by dividing the number of birth defects that occurred in the geographical vicinity of a grid location by the total number of births in the same vicinity. We test for significance, at regular spatial intervals, against the null hypothesis that the observed rate at any locality could reasonably have arisen by chance alone, given the underlying geographical variation in births. Significance is determined by using Monte Carlo simulations, where each birth location has an identical probability of being a defect. From 1000 simulations, a statistical distribution of the birth defect rate for each grid location is determined. The proportion of the simulated birth defect rates that are less than the observed rate at any grid location is the probability that the observed rate is significant. These probabilities, portrayed as isarithmic maps, show areas that have significantly high birth defect rates. Our results show birth defect rates for the period 1983 to 1990 in Des Moines, Iowa, U.S.A.

Cluster Analysis↗
PubMedDate not supplied

Frequency of prenatal diagnosis of birth defects in Houston, Galveston and the Lower Rio Grande Valley, Texas 1995.

BACKGROUND: Estimates of the proportion of birth defects diagnosed before birth exist for only a few types of birth defects and for a few geographic regions in the United States. This population-based study examines rates of prenatal diagnosis for previously unstudied birth defects in a new geographic region. METHODS: Active surveillance of 23 categories of birth defects among 111,902 infants born in 77 birthing hospitals in Texas in 1995 identified 852 infants or fetuses with major birth defects. Surveillance was conducted by the Texas Birth Defects Monitoring Program of the Texas Department of Health. Two regions were covered, the Houston/Galveston metropolitan area as well as the Lower Rio Grande Valley of Texas. Rates of prenatal diagnosis were evaluated for 23 different types of birth defects, using proportions and 95% confidence intervals. RESULTS: One third of the 852 infants or fetuses with birth defects were prenatally diagnosed. Diagnosis rates varied greatly depending on the type of birth defects and were lower among infants born to Black and Hispanic women. More than 60% of anencephaly, encephalocele, gastroschisis and trisomies 13 and 18 were diagnosed antenatally. Many of the fetuses that were electively terminated had birth defects or combinations of birth defects that were potentially lethal. Prevalence rates for birth defects generally do not include fetuses that die or are electively terminated before 20 weeks of gestation. Thus, 36% of anencephaly, 21% of omphalocele, 15% of encephalocele and between 7 and 10% of spina bifida, hydrocephaly, renal agenesis, and trisomies 13, 18, and 21 were not included in our published rates. CONCLUSIONS: Published rates for specific types of birth defects are spuriously low. This should be considered when investigating alleged clusters and comparing rates of birth defects across geographic areas. Since many elective abortions are for lethal or potentially lethal birth defects, a major effect of prenatal diagnosis is the resultant decrease in infant mortality attributable to birth defects.

Abortion, Induced↗
PubMed2005

Birth defects in Singapore: 1994-2000.

INTRODUCTION: To study characteristics of birth defect cases among live births, stillbirths and abortions in Singapore between 1994 and 2000. METHODS: Index cases for the National Birth Defects Registry (NBDR) were obtained from all neonatal nurseries in Singapore, all hospital discharge summaries, cytogenetic and pathology reports from all pathology laboratories in Singapore, and from the compulsory reporting of all termination of pregnancy cases and stillbirths delivered. Further information was obtained from case notes retrieved from the medical record offices, antenatal clinics, cytogenetic laboratories, pathology departments and the Registry of Births and Deaths. The notified cases (live births, stillbirths and abortions) between 1994 and 2000 were extracted from the NBDR and analysed with regard to ethnicity, maternal age, trend over the seven years and types of birth defects using the British Paediatric Association Classification. RESULTS: Between 1994 and 2000, a total of 7,870 cases (6,278 births and 1,592 abortuses) were notified, giving a rate of 23.99 birth defect cases per 1000 live births. There was a decreasing trend in birth defect incidence (19.76 to 16.85 per 1,000 live births) among live births and stillbirths and an increasing trend of abortion (3.25 to 7.57 per 1,000 live births) for birth defects. Malays had a higher rate of congenital defects at birth (24.4/1,000 live births) compared to Chinese (18.4/1,000 births). The 25-29 years age group had the lowest overall rate (22.6/1,000 live births) compared to the 19 years and below group at 31.6/1,000 live births and the 45-49 years group at 126.6/1,000 live births. The five most common groups of anomalies (per 1,000 live births) were those of heart (9.07), musculoskeletal (4.98), chromosomal (4.35), urinary (3.12) and nervous systems (2.90). The five most common aborted anomalies (per 1,000 live births) were those of chromosomal (2.40), nervous (1.23), heart (0.95), musculoskeletal (0.85) and urinary systems (0.36). CONCLUSION: There was an increasing trend of abortion for birth defects, accompanied by a falling trend in the congenital anomalies of live births. Both extremes of maternal age were at higher risk of non-chromosomal birth defects while advanced maternal age was at higher risk of chromosomal defects.

Adolescent↗
PubMedDate not supplied

Maternal residential exposure to hazardous wastes and risk of central nervous system and musculoskeletal birth defects.

The authors used a case-control design to evaluate the risk of central nervous system and musculoskeletal birth defects relative to exposure to solvents, metal, and pesticide contaminants from hazardous waste sites. Cases included 473 central-nervous-system-defect births and 3305 musculoskeletal-defect births to residents of 18 counties in New York State; controls comprised 12,436 randomly chosen normal births. For each address at birth, the authors assigned a probability of exposure to solvents, metals, and pesticides from hazardous waste sites in the study area (n = 643). They also rated residences by proximity to air releases from industrial facilities and by contamination of community water supplies. Compared with individuals for whom a low probability of exposure existed, mothers who resided in areas assigned a medium or high probability of exposure to hazardous waste contaminants did not show an increased risk of either type of birth defects. After adjusting for mother's race and age, prenatal care initiation, and population density, the resulting relative risks were as follows: central nervous system defects and exposure to solvents, 0.8 (95% confidence interval [CI] = .4, .6); central nervous system and metals, 1.0 (95% CI = 0.7, 1.7); musculoskeletal defects and solvents, 0.9 (95% CI = 0.5, 1.3); and musculoskeletal defects and pesticides, .8 (95% CI = .5, 1.3). With respect to central nervous system defects, there was an elevated risk associated with living near industrial facilities that emitted solvents (odds ratio = 1.3 [95% CI = 1.0, 1.7]) or metals (OR = 1.4, [95% CI = 1.0, 1.8]) into the air. The low proportion of individuals who had a medium or high probability of residential exposure to hazardous waste-site contaminants limited the investigation of particular pathways, disease subgroups, and/or geographic areas. Associations between central nervous system defects and industrial releases of solvents and metals need to be investigated further.

Adolescent↗
PubMed1994

On the use of affected controls to address recall bias in case-control studies of birth defects.

Inferences regarding causes of birth defects in humans are often based on results of case-control studies conducted after birth. To address bias in these studies caused by potential differential recall of past exposures between case and control mothers, many investigators have advocated the use of affected controls (babies with birth defects other than the one of interest). To evaluate whether the use of affected controls is warranted for a wide range of scenarios, we analyzed data from a population-based case-control study of birth defects in Atlanta, in which there were 4,918 babies with serious defects ascertained in the first year of life and 3,029 babies without defects. We compared the magnitude of the odds ratios for 10 specific defects--risk factor associations between normal and affected controls. These associations included demographic factors (e.g., advanced maternal age and Down syndrome), chronic maternal illnesses (e.g., diabetes and cardiac defects), chronic exposures (e.g., multivitamins and neural tube defects), and acute exposures (e.g., flu and neural tube defects). In all instances, the use of affected controls did not change etiologic inferences derived from using normal controls and there were only moderate changes in odds ratios. On the basis of theoretical considerations, we show that recall bias can lead to spurious inferences only under extreme conditions. We conclude that concerns about recall bias are overrated in birth defects studies and that the use of normal controls is acceptable unless evidence of substantial recall bias exists.

Case-Control Studies↗
PubMed2005

In vitro fertilization is associated with an increase in major birth defects.

OBJECTIVE: To determine the risk of major birth defects in cohorts of children conceived through IVF or through IUI as compared with naturally conceived children. DESIGN: Retrospective cohort study. SETTING: Academic medical center. PATIENT(S): Children conceived by IVF or IUI at the University of Iowa from 1989 through 2002, compared with a matched cohort of naturally conceived children. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Outcome data were obtained from Iowa state birth and fetal death certificates and from the Iowa Birth Defects Registry. RESULT(S): Ninety of 1,462 IVF-conceived children (6.2%) and 17 of 343 IUI-conceived children (5.0%) had a major birth defect, compared with 369 of 8,422 naturally conceived children (4.4%). The adjusted odds ratio of a major birth defect in all IVF-conceived children was 1.30 (95% confidence interval [CI] 1.00-1.67) and 1.11 (95% CI 0.67-1.84) for IUI-conceived children. The birth defect rate was increased after IVF when the analysis was limited to term singletons. Cardiovascular and musculoskeletal defects and known birth defect syndromes were increased after IVF. Among IVF-conceived children, there was no difference in birth defect rates after intracytoplasmic sperm injection (ICSI) or after transfer of cryopreserved embryos. CONCLUSION(S): Infants conceived through IVF have a slightly higher rate of major birth defects. More birth defects are noted among children born to infertile couples treated with IUI, although this difference is not statistically significant. Larger studies of infants conceived by infertile couples after all types of infertility treatment are needed to definitively determine whether the increased risk of birth defects is secondary to problems inherent in the infertile couple and/or factors associated with some aspect of the treatment.

Abnormalities, Multiple↗
PubMed2003

Parental occupations and other risk factors associated with nonchromosomal single, chromosomal single, and multiple birth defects: a population-based study in Singapore from 1994 to 1998.

OBJECTIVE: The purpose of this study was to evaluate the association between the prevalence of birth defects among maternal and paternal occupation groups in Singapore for live births between January 1, 1994, and December 31, 1998, and to determine whether there are certain demographic risk factors and maternal and/or paternal occupation groups that are associated with an increased risk for birth defects versus chromosomal single birth defect, nonchromosomal single birth defect, and multiple birth defects. STUDY DESIGN: This was a retrospective study. Information on live births (Singapore National Registry of Births and Deaths) and birth defect cases (National Birth Defects Register) were studied. Other information included the mother's date of birth, ethnic group, highest educational qualification, and the occupation of the mother and the father. Cox regression analysis was used to determine whether certain demographic and occupational factors were associated with the three groups of birth defects. RESULTS: Of a total of 237,755 live births, there were 3276 birth defect cases (nonchromosomal single birth defect, 1869 cases; chromosomal single birth defect, 197 cases; and multiple birth defects, 1210 cases). Increased risks for all types of birth defects were observed with advancing gestational age. Occurrence of nonchromosomal single birth defect and multiple birth defects were significantly higher for multiple births compared to singleton births. Significant associations were found with the use of "legislators, senior officers, and managers" as reference: Maternal occupation of "cleaners, laborers, and related workers" with chromosomal single birth defect anomalies (adjusted risk ratio, 4.86; 95% CI, 1.07-22.14); paternal occupation of "plant and machine operators and assemblers" (adjusted risk ratio, 1.50; 95% CI, 1.14-1.98) with nonchromosomal single birth defect; "production craftsmen and related workers" and "cleaners and laborers and related workers" with nonchromosomal single birth defect (adjusted risk ratio, 1.42; 95% CI, 1.10-1.82; and adjusted risk ratio, 1.43; 95% CI, 1.07-1.91 respectively); and multiple birth defects (adjusted risk ratio, 1.42; 95% CI, 1.03-1.94; and adjusted risk ratio, 1.47; 95% CI, 1.03-2.09, respectively). CONCLUSION: Maternal delivery age is an important risk factor for all birth defects. Mothers and fathers who work as "cleaners and laborers and related workers" appear to have a higher risk of giving birth to children with chromosomal single birth defect and nonchromosomal single birth defect and multiple birth defects, respectively. Further in-depth study would be needed to confirm these observations.

Abnormalities, Multiple↗
PubMed1989

[Survey of birth defects in Huixian].

A survey of births defects was made of 8,721 babies born in Huixian from May 1983 to January 1988. We identified 27 kinds of different physical defects and found 168 cases with congenital malformations (19.26%), slightly high on were defects related to nervous, gastrointestinal, locomotor and skin system. Incidence of physical defects among foetus and still births was evident higher than among live births. Among all the cases, the sex ratio was 1:106: incidence of birth defects was higher in mountainous areas than in the plain, and much lower in the first quarter of the year than in any other. Meanwhile, 28 suspected causative factors were further investigated and it was found that the incidence of birth defects was related to a history of birth defects of mental retardation of parents, certain illness during pregnancy and the intake of certain drugs during mother's pregnancy.

China↗
PubMed2001

Role of structural birth defects in preterm delivery.

The proportion of preterm births associated with structural birth defects has not been adequately quantified. We explored the proportion of preterm infants with structural birth defects diagnosed in the first year of life, as well as the specific phenotypes of birth defects occurring among preterm infants. The data used were from the California Birth Defects Monitoring Program, a population-based registry, as well as data from California vital records corresponding to births and fetal deaths in the period 1984-96. The prevalence of structural birth defects exceeded 8% among deliveries with gestational ages < or = 30 weeks, and prevalence decreased to 2% as gestational age increased to > or = 37 weeks gestation. The decreasing prevalence pattern with increasing gestational age was observed for a variety of anatomically defined birth defect groups suggesting that certain birth defects were not the sole contributors to the elevated prevalences among preterm births. Decreasing prevalence with increasing gestational age was also observed across strata of maternal race/ethnicities, ages, infant's sex and each year studied. These data indicate that structural birth defects may contribute significantly to the proportion of infants who are delivered before 37 weeks gestation.

Congenital Abnormalities↗
PubMed1980

Center for Birth Defects Information Services.

The Center for Birth Defects Information Services currently provides information in birth defects to medical centers. The D/A facility is designed to facilitate differential diagnosis and is being tested in preparation for general use sometime in 1981. A third facility is planned to classify and assist in identification of now unnamed and undiagnosed birth defects. This project when fully operative will assist clinicians in all phases of birth defects diagnosis so that they provide more quickly needed information to patients and their families.

Congenital Abnormalities↗