Increasing detection rates of birth defects by prenatal ultrasound leading to apparent increasing prevalence. Lessons learned from the population-based registry of birth defects of Barcelona

OBJECTIVE: To assess the evolving trends in prenatal ultrasound detection of birth defects and to suggest a method to avoid the bias generated by an increasing detection rate, when comparing different time periods. METHODS: In the population-based registry of birth defects of Barcelona (REDCB), 1976 cases with birth defects (1462 newborns and 514 terminations of pregnancy) were observed among 99 753 pregnancies, from 1992 to 1999. Detection rates for isolated birth defects by anatomical systems were evaluated. Since an increasing prevalence was observed in some birth defects systems, adjustment for detection rates was suggested. RESULTS: A rise in prevalence was observed in isolated birth defects involving internal organs (central nervous, respiratory, digestive, and urinary systems). Ultrasound detection rates increased in all system groups of isolated birth defects during the study period, except for cardiovascular defects. Early detection rates (before 23 weeks of pregnancy) increased in all but three systems (cardiovascular, genital and tegument). CONCLUSIONS: The apparent rise in the observed prevalence of certain birth defects may be largely due to improvements in prenatal detection methods. Population-based registries are able to measure the impact of evolving prenatal diagnosis in order to avoid biases and establish the prevalence of birth defects more accurately.     

广东省1996年至2004年监测出生缺陷发生情况分析

目的 了解广东省出生缺陷的变化趋势及其相关因素，为制定出生缺陷干预措施或政策提供科学的依据。方法 对1996年至2004年广东省出生缺陷监测数据进行回顾性描述分析和趋势分析。结果 1996年至2003年广东省总的平均出生缺陷发生率为134．4／万（7301／543062），2004年为212．2／万（2111／99483），出生缺陷发生率呈逐年上升的趋势；不同母亲年龄（P〈0．01）和围产儿性别（P〈0．01）间的出生缺陷发生率差别有统计学意义；36．5％的出生缺陷患儿母亲孕早期接触过不良因素；广东省常见的出生缺陷分别是先天性心脏病、胎儿水肿综合征、总唇腭裂、多指（趾）、先天性脑积水、先天性马蹄内翻足等；诊断依据以临床诊断和B超诊断为主。结论 广东省出生缺陷的干预措施仍需加强；干预措施要针对高发出生缺陷和高危因素制定。     

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.     

Epidemiologie von Fehlbildungen

The prevalence rates of congenital birth defects in Germany are useful for assessing the general background risk of having a child with a birth defect. At present, the risk of being born with a major malformation is about 5–7% in Germany. Epidemiological data on malformation from (birth-) registries represent the basis for determining regional and temporal prevalence trends for major malformations, for evaluating and initiating preventive measures, and for initiating research projects. Active monitoring systems should be required to avoid collection, observer and definition biases. The essential epidemiological knowledge for research on malformation is provided.     

Trends in neural tube defect prevalence,folic acid fortification,and vitamin supplement use

In this review, the authors analyze international trends in rates of neural tube defects (NTDs) during the past three decades. Population-based data sources include the Metropolitan Atlanta Congenital Defects Program and other US birth defects surveillance programs in the National Birth Defects Prevention Network, the International Clearinghouse for Birth Defects Monitoring Systems, and US and Canadian vital records. To analyze trends in vitamin consumption, we review data from the US National Health and Nutrition Examination Surveys and international surveys of multivitamin use. We discuss the role of factors associated with historic and continuing declines in NTD rates in most countries. These factors include the introduction and increased utilization of prenatal diagnosis, recommendations for multivitamin use in women of childbearing age, and population-wide increases in blood folate levels that have occurred since food fortification was mandated. We also discuss research needs for further NTD prevention. This is a US government work. There are no restrictions on its use.     

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.     

Frequency of human congenital malformations

Birth defects are important health problems. They are the leading cause of infant mortality, the fifth leading cause of premature years of life lost, and important contributors to our nation's chronic disease burden. Researchers have been successful in finding a few causes of birth defects; however, the etiology of the majority of birth defects remains unknown and thus hampers our ability to prevent these diseases. Clinicians who care for patients with birth defects can play an important role in etiologic research by developing good and testable etiologic hypotheses. Epidemiologists must then use these hypotheses and those provided by scientists working with experimental animals to design studies that can test these hypotheses.     

Birth defects data from surveillance hospitals in Dalian city,China, 2006–2010

Objective: The objective of this study is to disclose characteristics of birth defects in perinatal infants in Dalian and provide an epidemiological basis for controlling birth defects.

Methods: Data used in this study were collected from surveillance hospitals in Dalian during 2006–2010. Comparison analysis and trend analysis were conducted by performing Chi-square tests.

Results: The perinatal prevalence of birth defects from 2006 to 2010 was 101.14 per 10?000 live births and was decreased by about 29% from 115.49 per 10?000 live births in 2006 to 81.16 per 10?000 live births in 2010. The prevalence in urban was higher than that in rural areas significantly. The three leading birth defects were congenital heart disease, cleft lip and/or palate, and polydactyly or syndactyly. About 572 cases identified by antenatal diagnosis were terminated pregnancy before 28 weeks of gestation, so the prevalence of birth defects would decrease from 126.29/10?000 to 101.14/10?000.

Conclusions: Dalian has experienced a decreasing temporal trend of birth defects’ prevalence; however, it is still confronted with the challenge to reduce the prevalence of birth defects. Congenital heart diseases are the focus to prevent birth defects. It is necessary to keep the surveillance system function properly, provide preconception health care service extensively, and improve the ability of prenatal diagnosis.     

Maternal factors associated with severity of birth defects.

OBJECTIVE: Due to inbreeding and nutritional factors, the Bedouin Arabs represent a high risk population for birth defects. The severity of birth defects is probably related to the time and extent of interference with embryogenesis. The present study was aimed at identifying factors associated with severity of birth defects, in pregnancies of Bedouin women examined at a third level ultrasound clinic. METHODS: The study population consisted of 295 Bedouin women who attended an ultrasound clinic at the Soroka Medical Center between 1990 and 1996. The case group included 188 women carrying fetuses with severe birth defects, defined as incompatible with life or which significantly interfere with normal living. For those defects the option of pregnancy termination was discussed. The comparison group consisted of 107 women whose fetuses were diagnosed with mild defects. RESULTS: Women carrying fetuses with severe birth defects had more pregnancies and more deliveries than women carrying fetuses with mild defects (P = 0.005, P = 0.04, respectively). The severity of defects was found to be unrelated to maternal age, consanguinity, residence, birth order, previously uncompleted pregnancies and birth defects in the family. CONCLUSIONS: Higher birth order was associated with severity of birth defects detected at the second trimester.     

超声筛查在出生缺陷防控中的作用

文章阐述了二维超声、彩色多普勒、早孕期超声、中晚孕期超声及三维超声在出生缺陷防控中的临床应用价值及不足,指出二维超声和彩色多普勒仍然是最重要的出生缺陷筛查和诊断方法。产前超声医生接受严格规范标准化的培训,是保证超声筛查达到出生缺陷防控目标的基础。     

Prenatal Diagnosis in the 1990s

Prenatal diagnosis has become widely available and detects an increasing variety of birth defects and potentially harmful medical conditions. Many of the studies are complex and must be performed within a specific time period. Most prenatal diagnostic sampling techniques have some degree of risk for the mother or the fetus, and all produce at least transient anxiety. Nurses are involved in identifying families at risk, preparing women for the procedures, providing support, and counseling patients after the results are known; because of this role, nurses need updated information. This review describes current methods for early identification of a potential problem, discusses a variety of prenatal diagnostic procedures, reviews the most common types of laboratory studies, and introduces future trends in the field of prenatal diagnosis.     

鄂州市中心医院近2年新生儿出生缺陷监测报告

目的：探讨新生儿出生缺陷发病趋势,发现其发病的高危影响因素。方法：回顾分析在我院产科出生的近两年发病例数,有效的减少新生儿出生缺陷发生率。结果：鄂州市中心医院近两年出生的4094例新生儿中有25例出生缺陷患儿,出生缺陷的病种有多指,马蹄内翻足,先天性脑积水,外耳畸形,腹裂,尿道下裂,大脑发育异常,脑静脉瘤,血管瘤,面部黑痣,腰骶部突出物,腹腔积液等。结论：新生儿出生缺陷多与基因突变、遗传因素、孕妇生活的外在环境因素有关,做好新生儿出生缺陷的三级预防工作可明显降低新生儿出生缺陷率。     

Prevalence of birth defects and rubella infection in pregnant women in Gansu, west China. A survey

OBJECTIVE: To determine the incidence, disease types, sequence of birth defects and prevalence of IgG and IgM in rubella infection in prepregnancy and pregnancy within 3 months in Gansu, People's Republic of China, and to determine a baseline of birth defects for an intervention project on birth defects in Gansu. STUDY DESIGN: Liveborn and stillborn infants from January 1, 2001, to January 1, 2002, and 518 prepregnant and 373 pregnant women in 3 months in 4 counties, including 42 communities selected random by stratification cluster sampling for a survey on the economic and geographic features in the province in October 2001 were investigated. Every infant born in the study period was surveyed. The types of birth defects were classed by standard diagnostic codes (ICD-9). Five-milliliter blood samples were obtained from every prepregnant and pregnant women. Rubella IgG and IgM were measured by enzyme-linked immunosorbent assay. RESULTS: The overall number of birth defects in Gansu was 102 (16.35%). The incidence of birth defects by sex was 62 males (18.55%) and 40 females (13.9%). The types of birth defects were neural tube defect, 44 cases (7.07%); limb defects, 13 (2.09%); cleft lip and palate, 5 (0.8%); and Down syndrome, 3 (0.48%). Low birth weight occurred in 31 cases (4.98%). The seasonal incidence birth defects was spring, 24 cases (23.52%); summer, 31 (30.39%); autumn, 26 (25.49%); and winter, 21 (20.59%). There were significant differences between 4 counties. The death rate from birth defects was 48 cases (47.06%). The positive rates of IgM and IgG of rubella infection of prepregnant women were, respectively, 5.02% and 83.78%; in pregnant women they were, respectively, 2.41% and 86.33%. The seropositive rate of rubella infection of prepregnancy was 88.80%; that of pregnancy was 88.74%. CONCLUSION: The rate of rubella infection in prepregnant and pregnant women within 3 months in Gansu was one of the highest in the People's Republic of China. The rate of birth defects in Gansu was one of much higher than in the People's Republic of China as a whole.     

围生儿尸检500例病因分析及出生缺陷与胎盘病理变化的关系

目的：从500例围生儿尸检结果探讨围生儿死亡原因及出生缺陷和胎盘病理变化的关系。方法：根据1986年3月至2001年12月500例围生儿尸检结果，结合病史、胎盘病理检查分析其死亡原因。结果：新生儿主要死因是肺透明膜病和出生缺陷，死胎、死户主要是胎盘因素和出生缺陷；而出生缺陷儿的胎盘大多伴有病理性变化，如绒毛发育迟缓、胎盘感染等。结论：尸检及全面的胎盘检查对大多数死亡围生儿可提供有价值的信息。     

Neural Tube Defects: A Primary Prevention Role for Nurses

Neural tube defects are among the most common and serious birth defects. Most of these defects are caused by multifactorial inheritance. Research over the past decade has led to advances in understanding the etiology of these congenital anomalies. Folic acid has been shown to reduce the risk of first-time occurrence of neural tube defects as well as recurrent risk. Other genetic and environmental factors are under investigation. In this article, the nurse's role in the primary prevention of these birth defects is described.     

环境因素与出生缺陷

出生缺陷是围生儿死亡的主要原因之一,也是引起死胎、死产以及影响新生儿健康成长的重要原因.出生缺陷可因环境因素、遗传因素或两者的相互作用而发生.近年来,引起出生缺陷的环境因素成为研究热点.研究发现,出生缺陷与母亲妊娠期接触有害理化因素（如放射线、高温等物理性因素,铅、镉、锌、叶酸等化学性因素）,主动或被动吸烟、接触有机溶剂和环境污染物以及接触农业毒物、饮用水消毒副产物等有关.探讨环境因素与出生缺陷之间的关系可为减少出生缺陷提供理论依据.     

Secular trends in peri- and neonatal mortality in breech presentation; Norway 1967-1994

OBJECTIVES: To assess secular trends in mortality rates in breech presentation in Norway and the effects of gestational age, birth defects and delivery method. MATERIAL AND METHODS: The Medical Birth Registry of Norway 1967-1994, with 45,579 breech presentation births from 24 weeks of gestation onwards, with mortality rate comprising all stillbirths from 24 completed weeks of gestation and all neonatal deaths (extended peri- and neonatal mortality) as main outcome variable. RESULTS: The extended peri- and neonatal mortality rate in breech presentation births declined during the study period from 9.2% in 1967-76 to 5.5% in 1977-86 and to 3.0% in 1987-94. The highest relative risk of mortality in breech presentation versus the total birth population was observed in intrapartum death and in mortality less than 24 hours after delivery. Stillbirth represented about half of the extended peri- and neonatal mortality throughout the study period. Also in infants with birth defects, the survival increased during the study period. The extended peri- and neonatal mortality was highest in vaginal deliveries, but decreased during the period, irrespective of delivery method. CONCLUSIONS: Probably due to improved obstetrical and neonatal care, mortality associated with breech presentation has substantially decreased. Increased focus especially on stillbirth, might be instrumental in further reducing the mortality associated with breech presentation.     

Free radicals and birth defects.

Maternal diabetes significantly increases the risk for birth defects. Studies using animal models indicate that oxidative stress may play a causative role. Oxidative stress can result from exposure to certain drugs, ionizing radiation and folic acid deficiency. Therefore, study of the mechanisms by which maternal diabetes affects embryogenesis may provide insight into general processes by which birth defects occur. Study of embryonic gene expression has demonstrated that maternal diabetes causes birth defects by disturbing expression of genes that control essential developmental processes, and that oxidative stress is involved. A model in which oxidative stress-induced deficient gene expression leads to congenital defects involving p53-dependent apoptosis is discussed.     

The role of prenatal diagnosis in reducing the occurrence of birth defects in the pediatric population in the Czech Republic 1992-1997

The authors present data on the incidence of birth defects in liveborn infants up to the age of one year and the results of prenatal diagnosis of birth defects in the CR in 1997 and a brief comparison with the previous period 1992-1996. In the first part the authors present data on birth defects as whole, in the second part they present a comparison of the incidence of selected types of birth defects in 1997 with mean rates during the period 1961-1990. In the third part the comparison of results of prenatal diagnosis in the CR in 1997 is confronted with the period from 1992-1996.