A population-based study of coarctation of the aorta: comparisons of infants with and without associated ventricular septal defect

BACKGROUND

Coarctation of the aorta (CoA) is a congenital cardiovascular malformation (CCVM) sometimes associated with ventricular septal defect (VSD). Although the phenotypic association is well documented, little research exists on the epidemiological features distinguishing CoA with and without VSD.

METHODS

The Baltimore-Washington Infant Study (1981-1989), a population-based study of CCVM, evaluated 126 infants with "pure" CoA (free of associated cardiac defects) and 67 infants with CoA and VSD (COA/VSD) in comparison to 3,572 controls.

RESULTS

The proportion of infants with associated extracardiac anomalies was greater among CoA/VSD than among pure CoA (31% versus 11%). Infants with CoA/VSD were twice as likely as those with pure CoA to be born small for gestational age (23% versus 12%, respectively, compared with 6% of controls). All-cause mortality during the first year of life was higher in CoA/VSD than in pure CoA (21% vs. 7%). Multiple logistic regression models revealed that family history of CCVM was associated with pure CoA (adjusted case-control odds ratio [OR] = 4.6; 99% confidence interval [CI] = 1.5-13.9) and with CoA/VSD (OR = 5.9, CI = 1.2-23.5); maternal history of organic solvent exposures early in pregnancy was also associated with pure CoA (OR = 3.2, CI = 1.0-10.2) and with CoA/VSD (OR = 3.7, CI 0.9-14.9). Additional risk factors, including maternal epilepsy (OR = 5.3, CI = 0.9-30.6), and use of macrodantin (OR = 6.7, CI = 1.4-31.8) were associated only with pure CoA.

CONCLUSIONS

These findings highlight possible genetic and environmental differences between pure CoA and CoA/VSD and may stimulate further investigations of the etiology of CoA.

Vitamin A and cardiac outflow tract defects

To assess the relationship between maternal intake of vitamin A and cardiac outflow tract defects, we examined data from a population-based case-control study among liveborn infants born from 1987 through 1989 to mothers residing in the Baltimore-Washington area. Case infants (126) had a nonsyndromic cardiac outflow tract defect. Control infants (679) did not have birth defects and were a stratified random sample of liveborn infants from the same area. The main exposure was average daily maternal intake of retinol and provitamin A carotenoids from foods and supplements during the year before conception. Compared with an average intake of less than 10,000 IU, retinol intake of 10,000 IU or more from supplements was associated with a ninefold increased risk for transposition of the great arteries (odds ratio = 9.2; 95% confidence interval = 4.0-21.2), but not for outflow tract defects with normally related arteries (odds ratio = 0.8; 95% confidence interval = 0.1-6.6). Similar intakes of carotenoids and dietary retinol were not associated with an increased risk for either type of outflow tract defect.

Maternal diabetes: an independent risk factor for major cardiovascular malformations with increased mortality of affected infants

BACKGROUND

Intensive medical care of women with diabetes has reduced their risks of bearing infants with congenital anomalies. To assess the preventive potential of preconceptional care, the data of a population-based study of cardiovascular malformations (CVM) were analyzed to determine the morphogenetic specificity of maternal diabetes risks, the morbidity and mortality of the infants, and maternal characteristics that might affect these risks.

METHODS

The Baltimore-Washington Infant Study was a case-control study (1981-1989) that included all live born infants with confirmed CVM; control infants were a representative sample of the birth cohort. A questionnaire administered in home visits recorded parental information on social, medical, occupational, and environmental factors. For these analyses of preconceptional diabetes risks, the case group excluded chromosomal and mendelian disorders and was divided into 3 developmental categories and 12 diagnostic groups.

RESULTS

Preconceptional maternal diabetes was strongly associated with CVM of early embryonic origin (odds ratio [OR] = 4.7, 95% confidence interval [CI] 2.8-7.9) and with cardiomyopathy (OR = 15.1, 95% CI 5.5-41.3), but not with obstructive and shunting defects (OR = 1.4, 95% CI 0.7-3.0). There was heterogeneity within these developmental categories: among laterality defects, diabetes was associated only with cardiovisceral and atrioventricular discordance (OR = 10.0, 95% CI 3.7-27.0); among outflow tract anomalies, the risk was strongly associated with normally related great arteries (OR = 6.6, 95% CI 3.2-13.3) but not with simple transpositions; and among atrioventricular septal defects, diabetes was associated with the complete but not with the partial forms (OR = 22.8, 95% CI 7.4-70.5). The association in early CVM was strongest among infants with multisystem, predominantly VACTERL, anomalies. All-cause mortality of infants with CVM was 39% among those with diabetic mothers and 17.8% in those with nondiabetic mothers. Deceased infants of diabetic mothers were also more likely to have extracardiac anomalies (P = 0.041), to be born prematurely (P = 0.007), and to have low birth weight (P = 0.011). Multivariate analyses of maternal factors revealed no significant confounders of the diabetes associations.

CONCLUSIONS

The evidence of diabetes-induced major cardiac defects is of urgent clinical significance. The effectiveness of early preconceptional care in the prevention of congenital anomalies has been demonstrated repeatedly.

Association of transposition of the great arteries in infants with maternal exposures to herbicides and rodenticides

The Baltimore-Washington Infant Study, a case-control study of congenital heart defects in liveborn infants conducted in 1981--1989, interviewed parents about a wide range of environmental exposures that occurred during and before the pregnancy. In the period 1987--1989, the questionnaire was expanded to include a detailed inquiry about exposures to pesticides. An analysis of these latter data revealed an association of maternal exposure to any pesticides during the first trimester with transposition of the great arteries in their infants (TGA; n = 66 infants), relative to 771 control infants, with an odds ratio of 2.0 (95% confidence interval (CI): 1.2, 3.3). No other heart defects were associated with pesticides. When analyzed by type of pesticide and adjusted for covariates, there were associations of TGA with maternal exposures to herbicides (odds ratio (OR) = 2.8; 95% CI: 1.3, 7.2) and to rodenticidal chemicals (OR = 4.7; 95% CI: 1.4, 12.1) but not to insecticides (OR = 1.5; 95% CI: 0.9, 2.6). No data were collected on specific chemicals or brand names. These results raise new questions about the possible epidemiologic association of TGA with some classes of pesticides and warrant new, carefully targeted investigations.

Atrioventricular septal defects: possible etiologic differences between complete and partial defects

BACKGROUND

Recent advances in clinical, pathological, and genetic aspects of atrioventricular septal defects (AVSD) have set the stage for epidemiologic investigations into possible risk factors. Previous analyses of the total case group of AVSD included complete and partial subtypes without analysis of the subsets.

METHODS

To address the question of possible morphogenetic heterogeneity of AVSD, the Baltimore-Washington Infant Study data on live-born cases and controls (1981-1989) was reanalyzed for potential environmental and genetic risk-factor associations in complete AVSD (n = 213), with separate comparisons to the atrial (n = 75) and the ventricular (n = 32) forms of partial AVSD.

RESULTS

Complete and ventricular forms of AVSD had a similar proportion of isolated cases (12.2% and 15.6%, respectively, without associated extracardiac anomalies) and high rates of Down syndrome, whereas the atrial form of partial AVSD included 55% isolated cases. Trisomy 18 occurred in 22% of infants with the ventricular form, compared with <2% in the other AVSD groups. Analysis of potential risk factors revealed further distinctions. Complete AVSD as an isolated cardiac defect was strongly associated with maternal diabetes (odds ratio [OR] = 20.6; 95% confidence interval [CI] =5.6-76.4) and also with antitussive use (OR = 8.8; CI = 1.2-48.2); there were no strong associations other than maternal age among Down syndrome infants with this type of heart defect. Isolated cases with the atrial type of partial AVSD were associated with a family history of heart defects (OR = 6.2; CI = 1.4-24.4) and with paternal occupational exposures to ionizing radiation (OR = 5.1; CI = 1.4-27.4), but no risk factors were associated with Down syndrome. There were no significant associations of any risk factors in the numerically small subsets of isolated and Down syndrome cases with the ventricular form of partial AVSD.

CONCLUSIONS

These results indicate a similar risk profile of complete AVSD and the ventricular type of partial AVSD, with a possible subset of the latter due to trisomy 18. Maternal diabetes constituted a potentially preventable risk factor for the most severe, complete form of AVSD.

Maude E Abbott - physician and scientist of international fame

Dr Maude E Abbott (1869 to 1940) is the only Canadian and the only woman represented in Diego Rivera's great mural of the History of Cardiology in Mexico City. She gained this place among the world's famous physicians and scientists by her outstanding studies of congenital heart disease. Her atlas of 1000 cases with clinical, pathological and morphological findings is the first systematic study of these anomalies. Dr Abbott developed a pathophysiological classification of cardiovascular defects fundamental for the development of cardiac surgery. She also considered prevention by prenatal care, recognizing possible genetic and environmental risk factors. Maude Abbott was a thoughtful clinician and a brilliant scientist of incomparable industry. She leaves an unfinished legacy to make the prevention of congenital heart disease a reality.

Interrupted aortic arch: an epidemiologic study

BACKGROUND

Interruption of the aortic arch (IAA) is a rare but severe anomaly associated with major intracardiac defects and with multisystem noncardiac malformations, recently linked to chromosome deletion of 22q11.2.

METHODS

The Baltimore-Washington Infant Study (1981-1989), a population-based epidemiologic study of cardiovascular malformations, evaluated 53 infants with IAA in comparison with 3,572 controls. Risk factors for the anatomic subtypes were evaluated in 14 cases of IAA type A and 32 cases of IAA type B, but no molecular genetic tests were available. The distribution of associated cardiac defects was similar for both types.

RESULTS

DiGeorge syndrome (DGS) occurred more frequently in IAA type B. Case-control comparisons demonstrated that infants in both groups were growth retarded at birth. A family history of noncardiac defects occurred only in IAA type B cases and included relatives with cleft lip and/or cleft palate. Candidate risk factors were associated only in type B cases and differed for those with (n = 10) and for those without (n = 19) DGS: a family history of noncardiac defects (odds ratio [OR] = 7.2, 95% confidence interval [CI] = 1.5-39.2) and maternal use of aspirin during the critical period (OR = 4.8, 95% CI = 1.3-25.4) occurred with DGS, while previous stillbirth (OR = 9.4, 95% CI = 1.3-53.1), bleeding during pregnancy (OR = 3.7, 95% CI = 1.4-11.4), and maternal exposure to arts/crafts paints (OR = 4.8, 95% CI = 1.3-17.4) were associated in those without DGS.

CONCLUSIONS

These findings confirm the heterogeneity of IAA and of the type B subtype. Risk factors specific for cases with DGS may open a window to further investigations of the etiology of IAA and of the associated molecular genetic abnormalities.

Failure to diagnose congenital heart disease in infancy

OBJECTIVE

To identify factors that predict failure to diagnose congenital heart disease in newborns.

DESIGN

All fatal cases in the Baltimore-Washington Infant Study were compiled. The Baltimore-Washington Infant Study includes 4390 cases of infants with congenital cardiovascular malformations identified in a population-based study between 1981 and 1989 in the Baltimore-Washington metropolitan area. Death occurred in 800 such infants in the first year of life. In 76 of these infants, death occurred before diagnosis of heart disease. These cases were identified by community search of autopsy records. Their characteristics are compared with those of infants who died after a cardiac diagnosis was made.

RESULTS

Infant characteristics (birth weight, gestational age, intrauterine growth retardation, and chromosomal anomaly) are associated with death of infants with congenital cardiovascular malformations and with death of such infants before diagnosis. Diagnoses of coarctation of the aorta, Ebstein's anomaly, atrial septal defect, and truncus arteriosus are overrepresented in infants found by community search, particularly in those infants without associated malformations. Paternal education is associated with failure to diagnose congenital heart disease in life but other sociodemographic characteristics of the infant's family are not.

CONCLUSIONS

Diagnosis of congenital cardiovascular malformations requires close observation in the neonatal period. Analysis of age at death of infants with undiagnosed congenital cardiovascular malformation suggests that such infants may be at risk if discharged within the first 2 days of life.

Paternal exposures and cardiovascular malformations. The Baltimore-Washington Infant Study Group

Possible associations between paternal exposures and cardiovascular malformations were evaluated in the Baltimore-Washington Infant Study, a population based case-control investigation of congenital heart disease and environmental factors. Home interviews of case and control parents elicited information on parental home and occupational exposures. Analysis focused on twelve cardiac diagnostic groups and paternal exposures incurred during the six months preceding the pregnancy. Associations were identified between jewelry making and atrial septal defect (Odds ratio: 12.6; 95% confidence interval: 2.3-68.6) and membranous ventricular septal defect (8.1; 2.0-33.3), welding and endocardial cushion defect with Down syndrome (1.8; 1.1-3.0), lead soldering and pulmonary atresia (2.3; 1.1-4.9) and ionizing radiation and endocardial cushion defect without Down syndrome (4.7; 1.7-12.6). Ionizing radiation was found to be associated with endocardial cushion defect with Down syndrome only when father was present at interview (5.6; 1.7-17.9); a similar effect of father at interview was noted for paint stripping in relation to coarctation of the aorta (3.5; 1.5-8.0) and muscular ventricular septal defect (3.5; 1.5-8.5). Also, paint stripping was associated with hypoplastic left heart only in the presence of family history of cardiac defects (11.9; 2.4-60.0). This large study on cardiac diagnostic groups and specific preconceptional exposures provides new leads for further assessment of the role of paternal exposures on adverse pregnancy outcome.

Attributable fraction for cardiac malformations

To the authors' knowledge, attributable fractions for cardiac malformations have not been reported before. The Baltimore-Washington Infant Study published factors associated with several major cardiac malformations in Maryland, the District of Columbia, and adjacent counties of northern Virginia in 1981-1989. For eight of these malformations, the authors provide attributable fractions of those factors that are potentially causal. Summary attributable fractions range from 13.6% (four factors) for hypoplastic left heart to 30.2% (seven factors) for transposition of great arteries with intact ventricular septum. Extra attributable fraction for factor x, defined as summary attributable fraction for all factors minus that for all but x, is largest for: 1) paternal marijuana use in transposition of great arteries with intact ventricular septum, 7.8%; 2) paternal anesthesia in tetralogy of Fallot, 3.6%; 3) painting in atrioventricular septal defect with Down syndrome, 5.1 %; 4) solvent/degreasing agent exposure in hypoplastic left heart, 4.6%; 5) sympathomimetics in coarctation of aorta, 5.8%; 6) pesticide exposure in isolated membranous ventricular septal defect, 5.5%; 7) hair dye in multiple/multiplex membranous ventricular septal defect, 3.3%; and 8) urinary tract infection in atrial septal defect, 6.4%. Percent-of-cases-exposed dominates relative risk in attributable fraction. If these factors are causal, the larger extra attributable fractions suggest the potential for prevention by specific interventions before/during pregnancy.

Preconceptional folate intake and malformations of the cardiac outflow tract. Baltimore-Washington Infant Study Group

We compared cases with outflow tract defects (N = 126) with controls representative of the same birth cohort (N = 679). Infants with clinically recognized syndromes were excluded. Daily total maternal folate intake of > or =245 microg was inversely related to risk of cardiac outflow tract defects among those with transposition (odds ratio estimates: 0.65, 0.78, and 0.76 with increasing quartile of daily folate intake), but positively related among those with normally related vessels (corresponding odds ratio estimates: 1.18, 1.59, and 1.68). This difference disappeared when maternal intake of supplemental folic acid of > or =400 microg compared with <400 microg was considered, excluding dietary intake [odds ratio (OR) = 1.04; 95% confidence interval (CI) = 0.5-2.2 for infants with transposition, and OR = 0.91; 95% CI = 0.5-1.8 for those without transposition of the great arteries].

VACTERL-hydrocephaly, DK-phocomelia, and cerebro-cardio-radio-reno-rectal community

Phenotypic manifestations of the autosomal recessive form of VACTERL-hydrocephaly syndrome (David-O'Callaghan syndrome) and the X-linked recessive form (Hunter-MacMurray) syndrome are almost identical. The absence of cardiovascular malformations in cases with undoubtedly X-linked inheritance may be the only exception. The comparison of patients with David-O'Callaghan syndrome and nonclassified sporadic cases of VACTERL-hydrocephaly showed two marked differences. First, radial involvement (usually bilateral) occurred in all familial but only in 22 of 36 sporadic cases. Therefore, radial noninvolvement may be evidence against a genetic origin of the complex in a sporadic case. Second, predominantly severe forms of cardiovascular malformations were found in cases of David-O'Callaghan syndrome, whereas in sporadic cases almost all cardiovascular malformations were simple defects with minimal, if any, hemodynamic disturbances. The similarity of the spectrum and frequency of main manifestations of David-O'Callaghan and von Voss-Cherstvoy syndromes allows us to think that both of these syndromes actually might be 2 forms of one genetic entity. There are some syndromes with abnormalities of the brain (different for each syndrome) sharing the same limb defects (mainly preaxial), congenital heart defects, abnormalities of kidneys, and anal atresia/ectopia. Baller-Gerold syndrome, Steinfeld syndrome, XK-aprosencephaly, and DK-phocomelia (von Voss-Cherstvoy) syndrome as well as Mendelian forms of VACTERL-hydrocephaly syndromes fit into this "cerebro-cardio-radio-reno-rectal community."

"Shifted" threshold may explain diversity of cardiovascular malformations in multiple congenital abnormalities syndromes: 3C (Ritscher-Schinzel) syndrome as an example

The analysis of cardiovascular malformations (CVM) in 3C (Ritscher-Schinzel) syndrome showed at least 9 types of CVM in 24 cases, including 4 cases from the Baltimore-Washington Infant Study. The proportion of different CVM forms was similar to that of the general population. The same is also true for many other syndromes of multiple congenital abnormalities (MCA), due either to aneuploidy or to Mendelian mutation. Such a wide spectrum of very different CVM in patients with the same entity has yet to be explained. According to the hypothesis proposed, the basic mutation (or chromosome imbalance) affects cellular homeostasis and leads to the "shifting" of a threshold to the left. This allows the expression of some genes silent under normal conditions. The principle of the shifted threshold is applicable to the explanation of the origin of many other defects in MCA syndromes.

Non-cardiac malformations in individuals with outflow tract defects of the heart: the Baltimore-Washington Infant Study (1981-1989)

In the Baltimore-Washington Infant Study, a regional case-control study of 4,390 liveborn infants with cardiovascular malformations (CVM), 642 patients (14.2%) had outflow tract abnormalities, with extracardiac defects in 157 (approximately 25%) of them. Associated defects were found in 1/3 of patients with normal great arteries, but only in 1/10 of patients with transposition of great arteries (TGA). The extracardiac defects were especially rare in the groups "TGA with intact ventricular septum" and "TGA with ventricular septal defect". Patients with multiple associated defects outnumbered patients with isolated associated defects in the ratio 2.5:1. The associated defects were heterogeneous: 46 patients had chromosome abnormalities, 16 had different Mendelian syndromes, and 36 had associations (DiGeorge sequence and VACTERL association were the most frequent). A new syndrome of multiple congenital abnormalities including tetralogy of Fallot, and rare cases of chromosomal and Mendelian syndromes (distal trisomy 1q, tetrasomy 8p, Holzgreve syndrome) are described briefly. Sufficient variability of a spectrum of conotruncal defects in the patients with the same chromosomal or Mendelian syndromes suggests that at least in some cases different conotruncal defects are stages of the same morphologic spectrum. The analysis of conotruncal defects in sibs of patients with Mendelian syndromes may provide new data about the links between different definitive forms of CVM.

'Microgastria--limb reduction' complex with congenital heart disease and twinning

We report a newborn, the second of male twins, with multiple abnormalities, including microphthalmia, a complex cardiovascular malformation, asplenia, anomalous lobation of the lungs, oesophageal atresia, microgastria, intestinal malrotation, anal atresia, multicystic dysplastic kidneys, and reduction defects of the upper extremities. These defects fit into the so-called 'microgastria-limb reduction' complex. Two of twelve previously reported patients with this complex were from discordant twin pairs. The occurrence of twinning in three out of 13 cases suggests that the origin of the 'microgastria-limb reduction' complex may be related to the process of twinning itself.

Ebstein's malformation of the tricuspid valve: genetic and environmental factors. The Baltimore-Washington Infant Study Group

Ebstein's anomaly is a specific structural deformity of the tricuspid valve, and its rarity has hampered etiologic evaluation. Cases of Ebstein's anomaly registered in the Baltimore Washington Infant Study (BWIS), a regional case-control study of cardiovascular malformations (CVM) in infancy, are reviewed. Between 1981 and 1989 a total of 4,390 CVM cases, including 47 Ebstein cases, and 3,572 controls were registered. The prevalence of Ebstein's anomaly was 5.2 per 100,000 livebirths. Additional cardiac anomalies were present in 38.3% of Ebstein cases. Non-cardiac malformations were present in 19.1% of Ebstein cases vs. 25.5% of other CVM, and 1.7% of controls. Case-fatality by 1 year of age was 23.4% in Ebstein vs. 18.1% in other CVM. Interviews of parents of Ebstein cases, other CVM, and controls (n = 44, 3,335, and 3,572, respectively) elicited information on family history of malformations, maternal illnesses, reproductive history, therapeutic drugs, parental lifestyle, and environmental exposures during the periconceptional period. Case-control analyses suggest genetic, reproductive, and environmental risk factors: twins [odds ratio (OR) 8.2, 95% confidence interval (CI) 2.6-25.3]; family history of CVM (OR 6.4, 95% CI 1.8-22.2); white race (OR 2.9 with non-whites as reference, 95% CI 1.2-7.0); previous miscarriages (OR 2.0, 95% CI 1.2-3.3); maternal exposure to benzodiazepines (OR 5.4, 95% CI 1.5-19.1); and varnishing (OR 3.4, 95% CI 1.3-9.1). Additional multicenter investigations are warranted to elucidate the role of genetic, reproductive, and environmental factors in the etiology of this anomaly.

Congenital heart disease in adolescents and adults. Teratology, genetics, and recurrence risks

This brief review has described historic highlights of etiologic knowledge, current concepts in the categorization of cardiovascular anomalies based upon ongoing advances in teratology, and epidemiologic evaluations of biologic and xenobiotic risk factors with emphasis on the teratogenic roles of maternal diabetes, hyperphenylalaninemia, and parental exposures to alcohol, drugs, solvents, pesticides, lead, and other toxic substances. Evidence is presented for a strong genetic basis of cardiovascular maldevelopment requiring further studies to define at-risk families. Counseling and personal and societal preventive interventions may reduce the occurrence of some forms of CHD.

Use of prescription and non-prescription drugs in pregnancy. The Baltimore-Washington Infant Study Group

We analyzed use of therapeutic drugs during pregnancy by 2752 mothers of infants without major congenital malformations. During pregnancy, 68% of the women used at least one prescription or non-prescription drug. Drug use in pregnancy was significantly more common for women who were white, older, married, better educated, of higher income and occupational status, receiving private prenatal care and not living in urban areas. Number of maternal illnesses, higher socioeconomic status, white race, multiparity and use of recreational drugs explained 26% of reported drug use. The mean number of drugs reported (1.2) underestimates total drug exposure due to exclusion of some drug categories including multivitamins and illicit drugs. Since the majority of women giving birth to normal infants report use of at least one pharmacologic agent during pregnancy, attribution of adverse outcome to drug use in an individual case is rarely justified.

Temporal trends in prevalence of cardiovascular malformations in Maryland and the District of Columbia, 1981-1988. The Baltimore-Washington Infant Study Group

We studied the yearly occurrence of isolated cardiovascular malformations in liveborns for the period 1981-1988 in Maryland and the District of Columbia. We used Poisson regression to fit yearly prevalence at birth as a function of time for all cardiovascular malformation case types combined and for three diagnostic subgroups. We give results separately by diagnostic method and race (white/nonwhite), with categories combined when appropriate. Time trends were similar for both races except in pulmonic stenosis diagnosed by echocardiography. The yearly prevalence for all case types, all races, and all diagnostic methods combined increased from 28 to 43 per 10,000 livebirths over the 8 years, due to an increase in the rate among infants diagnosed by echocardiography. For every diagnostic-type-by-race group studied, there were increases in the prevalence for those diagnosed by echocardiography and decreases (or no change in one group) for those diagnosed by cardiac catheterization and/or surgery. Although there may have been an increase in actual occurrence of cardiovascular malformation over our study period, it is also possible that wider use of a new echocardiography technology resulted in increased detection.

Endocardial cushion defect: further studies of "isolated" versus "syndromic" occurrence

The isolated occurrence of endocardial cushion defect (ECD) has been suggested to differ from its occurrence within the context of a syndrome, with regard to the nature (complete or partial) of the defect and the associated cardiovascular malformations. Analysis of data derived from the Baltimore-Washington Infant Study of congenital cardiovascular malformations supports the observation that "syndromic" ECD tends to be of the complete atrioventricular canal type and is less frequently associated with left cardiac anomalies than the isolated form. However, each syndrome has a unique impact on the overall cardiovascular "phenotype", including the ECD. This is especially true for Down and Ivemark syndromes, which are most frequently associated with ECD, but also for other syndromes as well. It is also suggested that isolated ECD is specifically associated with gastrointestinal and urinary tract anomalies. However, in Down syndrome ECD appears to be a specific cardiovascular expression of the trisomic state that is unrelated to other noncardiac malformations. Additional information on the association of ECD with other less common genetic syndromes is needed in order to further investigate the possible genetic basis of this cardiac defect.

Cardiomyopathy in infancy: observations in an epidemiologic study

Cardiomyopathy (Cm), a rare form of cardiac disease in infancy, is receiving increasing attention stimulated by the availability of endocardial biopsy and new forms of therapy. Population-based information on frequency of occurrence, types, and maternal and infant characteristics of this diverse group of heart muscle disorders has been obtained in the course of an etiologic study on cardiovascular disease in infancy. The Baltimore-Washington Infant Study (BWIS) enrolled 2659 infants with heart disease and 2801 control infants between January 1, 1981 and March 31, 1987, a 6-year prevalence of 4.46/1000 live births. Fifty-six infants had cardiomyopathy, in the absence of a structural defect (prevalence 1/10,000). The cases were classified clinicopathologically as follows: dilated Cm (n = 17), hypertrophic Cm (n = 26), tumor (n = 5), endocardial fibroelastosis (n = 5), glycogen storage (n = 1), mucocutaneous lymph node syndrome (n = 1), and infarction (n = 1). Eleven syndromic associations and six metabolic disturbances indicate genetic risk factors. Some of the same syndromes occurred in other infants who had structural cardiac abnormalities. This overlap suggests that embryonic myocardial disease might sometimes be responsible for altered cardiac structures, possibly secondary to hemodynamic changes. Familial myocardial disease occurred in two infants with hypertrophic Cm. The Cm group did not differ by race and sex from controls, but the mothers were of lower educational and occupational status with less private care and with later registration for pregnancy care. The descriptive epidemiology of this population-based case group provides evidence of greater etiologic heterogeneity than has been shown in clinical reports.

Total anomalous pulmonary venous return: familial and environmental factors. The Baltimore-Washington Infant Study Group

In total anomalous pulmonary venous return (TAPVR), the intrapulmonary venous plexus has failed to connect to the left atrium, so that the pulmonary veins drain into right atrial tributaries, frequently resulting in early postnatal circulatory distress. The Baltimore-Washington Infant Study (BWIS), a population-based exploratory case-control study of cardiovascular malformations (CVM), identified 41 cases of TAPVR during 1981-1987: 1.5% of all CVM (N = 2659), a regional prevalence of 6.8/100,000 live births. Of the TAPVR infants, 68% were diagnosed as neonates, 88% had surgery, and 51.2% were alive at 1 year of age. Noncardiac malformations were present in nine cases (22%); the male-female ratio was 0.78 (18.23). Compared with a control group representative of the birth cohort (N = 2,801), more TAPVR patients had low birthweight (less than 2,500 g: 16.2% vs. 6.9%, short gestational age (less than 38 weeks: 18.9% vs. 9.3%), and intrauterine growth retardation (IUGR) (26.8% vs. 5.8%). Sociodemographic findings were similar to those of controls, except that fewer TAPVR mothers received private pregnancy care (59.5% vs. 71.4%). Family history revealed no other TAPVR-affected members, but a significant linear trend of increased risk was found over the ordered malformation categories (familial noncardiac, cardiac, both). Bivariate analysis of TAPVR and exposure in life-style, hobbies, and work showed possible associations for exposure to lead (OR 2.9; 99% confidence interval [CI]: 1.2, 7.2), painting/paint stripping (OR 3.3; 99% CI: 1.3, 8.4), lead soldering (OR 13.3; 99% CI: 1.8, 99.2), and pesticides (OR 2.7; 99% CI: 1.2, 6.4). Multivariate analysis suggested an interaction between pesticide exposure and family history and, thus, a possible familial susceptibility to environmental teratogens. Although the number of TAPVR cases is small, this epidemiologic study identifies hypotheses that may be further explored in morphogenetic and epidemiology studies. Total anomalous pulmonary venous return (TAPVR) constitutes a well-defined clinical entity in which the pulmonary veins fail to enter the left atrium and instead drain into the right atrium or its systemic venous tributaries (Neill, '56; Rowe et al., '81). During intrauterine life, the malformation does not compromise the fetal circulation, since the pulmonary arterial resistance is high and the patent foramen ovale provides easy access of right atrial blood to the left side of the heart. At birth, however, the pulmonary vascular resistance begins to fall, and the presence of a severe hemodynamic disturbance becomes increasingly evident (Ferencz et al., '71).(ABSTRACT TRUNCATED AT 400 WORDS)

White-black differences in cardiovascular malformations in infancy and socioeconomic factors. The Baltimore-Washington Infant Study Group

Cardiovascular malformations were examined for white/black variation in the Baltimore-Washington Infant Study. In this population-based case-control study, cases (n = 2,087) were live births with cardiovascular malformations ascertained through pediatric cardiology centers and 53 hospitals in Maryland, the District of Columbia, and northern Virginia between 1981 and 1987. Controls (n = 2,721) were a random sample of infants from the live-birth cohort that gave rise to the cases. The proportion of infants that were white was similar for all cases as a group and controls (0.68 and 0.67, respectively). Subgroup analysis, however, revealed an excess of white infants among cases with Ebstein's anomaly (odds ratio (OR) = 3.7, 95% confidence interval (Cl) 1.1-12.5), aortic stenosis (OR = 3.6, 95% Cl 1.7-7.6), pulmonary atresia (OR = 2.5, 95% Cl 1.0-6.1), coarctation of the aorta (OR = 2.2, 95% Cl 1.4-3.5), and D-transposition of the great arteries (OR = 1.6, 95% Cl 1.1-2.5), and a deficit of white infants among cases with pulmonary stenosis (OR = 0.6, 95% Cl 0.4-0.8) and heterotaxia (OR = 0.4, 95% Cl 0.3-0.8). These associations remained when cases were stratified by infant's age or by method of diagnosis. Controlling for socioeconomic factors attenuated the white excess for Ebstein's anomaly (OR = 3.0, 95% Cl 0.9-10.5), disclosed a white excess among cases of L-transposition of the great arteries (OR = 2.8, 95% Cl 1.0-8.0), and revealed that the white excess for aortic stenosis was limited to low and middle socioeconomic strata. These results highlight racial variations in cardiovascular malformations, suggest that socioeconomic factors account for some of this variation, and identify malformation subgroups for which further evaluation of sociocultural, environmental, and familial factors is needed.

Birth weight and cardiovascular malformations: a population-based study. The Baltimore-Washington Infant Study

Mean birth weights were evaluated in infants with D-transposition of the great arteries, tetralogy of Fallot, endocardial cushion defect, hypoplastic left heart syndrome, pulmonary stenosis, aortic stenosis, coarctation of the aorta, ventricular septal defect, and atrial septal defect in a population-based case-control study of congenital cardiovascular malformations in residents of Maryland, Washington, D.C., and northern Virginia (1981-1987). Study subjects were liveborn singletons without extracardiac anomalies. After adjustment for potentially confounding maternal, gestational, and infant factors, significant birth weight deficits were found for infants with tetralogy of Fallot, endocardial cushion defect, hypoplastic left heart syndrome, pulmonary stenosis, coarctation of the aorta, ventricular septal defect, and atrial septal defect. After adjustment, infants with these malformations (except coarctation of the aorta and atrial septal defect) were also significantly more likely than were controls to have low birth weight for gestational age. These findings strengthen previous evidence that certain cardiovascular malformations and low birth weight may be causally related.

Maternal diabetes and cardiovascular malformations: predominance of double outlet right ventricle and truncus arteriosus

Most studies on the relationship of maternal diabetes to cardiovascular malformations (CVM) have been prospective investigations of pregnancy outcome and therefore could not identify associations with rare cardiac lesions. The results of a retrospective study shed new light on the risks of specific cardiac defects in diabetic pregnancies. The Baltimore-Washington Infant Study, a population-based case-control investigation of CVM, provides information on maternal diabetes reported in personal interviews. Among 2259 mothers of cases, 35 (1.5%) reported diabetes present before pregnancy (called "overt") and 95 (4.2%) reported diabetes only during pregnancy (called "gestational"). Among 2,801 mothers of controls, 14 (0.5%) had overt diabetes and 83 (3.0%) had gestational diabetes. Malformation-specific risks were expressed as odds ratios (OR) with 99.5% confidence intervals (CI). The strongest associations with overt maternal diabetes were found with double outlet right ventricle (OR 21.33; 99.5% CI 3.34, 136.26), and truncus arteriosus (OR 12.81; 99.5% CI 1.43, 114.64). No significant diagnosis-specific associations were found with gestational diabetes. Non-cardiac malformations were present in 23% of infants with CVM whose mothers had overt diabetes and in 26% of infants with CVM whose mother had gestational diabetes, in 32% of infants with CVM whose mothers did not have diabetes, and in 4% of controls. Double outlet right ventricle and truncus arteriosus are malformations dependent upon neural-crest-cell-derived ectomesenchymal tissues; these are precisely the conotruncal abnormalities that result from experimental ablation of the neural crest in chick embryos. The association with diabetes suggests a further etiologic link between these two lesions.

Congenital cardiovascular malformations in twins and triplets from a population-based study

Data from the Baltimore-Washington Infant Study of congenital cardiovascular malformations permitted detailed analysis of congenital cardiovascular malformations in 62 twins and 3 triplets and 2303 singleton cases. A probability sample of controls (n = 2793) included 43 twins. The case prevalence of multiple births was 28 of 1000, compared with a 15 of 1000 prevalence among controls (chi 2 = 5.7). There were more girls among case twins than among case singletons and controls (chi 2 = 9.0). Monozygosity was no more frequent in case twins than in controls. Looping defects occurred in 4 monozygotic twin pairs compared with only 1 dizygotic twin pair. The twinning process itself may be implicated in the development of congenital cardiovascular malformations in some of these infants, especially those with looping defects, but concordance of types of defects in 4 of 65 pairs implicates genetic factors in the determination of some forms of congenital cardiovascular malformations.

Congenital cardiovascular malformations: questions on inheritance. Baltimore-Washington Infant Study Group

The Baltimore-Washington Infant Study, an epidemiologic investigation of congenital heart disease, searches for genetic and environmental risk factors. Among 2,102 infants with heart disease, 17.5% had a noncardiac abnormality of chromosomal or genetic origin, whereas among 2,328 control infants, only 0.7% had a genetic abnormality. Familial cardiovascular malformations encountered can be grouped into five distinct etiologic mechanisms. Single gene effects may be responsible for the specific histologic and biochemical changes in familial atrial septal defect with conduction disturbance and also in idiopathic ventricular hypertrophy. Left heart lesions showed familial concordance by the presumed morphogenetic mechanism of abnormal embryonic blood flow with phenotypes of varying severity. Pulmonary stenosis appeared with familial heritable disorders, as well as a partially concordant lesion with tetralogy of Fallot. Ventricular septal defect with transposition of the great arteries (one sibling pair) and with truncus arteriosus (two sibling pairs) indicate forme fruste expression of conotruncal defects. Endocardial cushion defect occurred with and without Down's syndrome in members of three families, suggesting inheritance of a defect affecting cellular migration. Heritable blood coagulopathies occurred in case families and not in control families. The associated of hemophilia and transposition, observed also by others, is extremely unlikely by chance and suggests genetic errors of endothelial cell function. The description of specific families from a population-based study emphasizes biologic questions on the nature of the inheritance of cardiovascular malformations.

Increased prevalence of ventricular septal defect: epidemic or improved diagnosis

The Baltimore-Washington Infant Study is an ongoing case-control study of congenital cardiovascular malformations in infants in whom the clinical diagnoses have been confirmed by echocardiography, catheterization, surgery, or autopsy. An increase in the prevalence of ventricular septal defects was detected in 1,494 infants with congenital cardiovascular malformations between 1981 and 1984. The prevalence of congenital cardiovascular malformations increased from 3.6 to 4.5 per 1,000 live births (P less than .025) and the prevalence of ventricular septal defect increased from 1.0 to 1.6 per 1,000 live births (P less than .001). The increase in ventricular septal defects accounted for the total increase in congenital cardiovascular malformations. The prevalence of isolated ventricular septal defect increased from 0.67 to 1.17 per 1,000 live births (P less than .001). The prevalence of ventricular septal defect with associated coarctation of the aorta, patent ductus arteriosus, atrial septal defect, and pulmonic stenosis did not change. The prevalence of ventricular septal defect diagnosed by catheterization, surgery, and autopsy did not change; however, defects diagnosed by echocardiography increased from 0.30 to 0.70 per 1,000 live births (P less than .001). It is concluded that the reported increase in prevalence of ventricular septal defect is due to improved detection of small, isolated ventricular septal defects and that there is no evidence of an "epidemic."

Origin of congenital heart disease: reflections on Maude Abbott's work

In honour of Dr Harold Segall's 90th birthday an historical review was made of concepts on the etiology of congenital heart disease. The work of Maude Abbott, highlighted in alignment with early results of an ongoing population based study, illustrates her remarkable perception of a kaleidoscope of risk factors which are now gaining acceptance. Abbott's letters to L. Emmett Holt express her belief that prenatal infections cause cardiac maldevelopment, but she also raises relevant questions on the potential role of inheritance. The Baltimore-Washington Infant Study (1981-86) reveals a predominance of genetic factors, evidence of intrauterine infection and of a teratogenic effect of maternal diabetes. Among environmental agents, alcohol and recreational drug intake appear to affect cardiac looping. Harold Segall's historical interests and continued professional activities demonstrate the validity of his scholastic motto: "It is good to know."

Congenital cardiovascular malformations associated with chromosome abnormalities: an epidemiologic study

The Baltimore-Washington Infant Study is a population-based case-control study that seeks to identify risk factors for cardiovascular malformations. Between 1981 and 1986, a total of 2102 infants with cardiovascular malformations were ascertained, among whom 271 (12.9%) also had a chromosome abnormality. Among 2328 random control subjects, only two had a chromosome abnormality. Down syndrome with cardiovascular malformations had a maternal age-adjusted regional prevalence of 4.33/10,000 for the white population and 3.70/10,000 for the nonwhite population. Endocardial cushion defect, the predominant cardiac abnormality in Down syndrome (60.1%), rarely occurred as an isolated cardiac lesion (2.8%). The absence of transpositions and the rarity of heterotaxias and of right- and left-sided obstructive lesions in trisomies indicate that there may be a genetic influence on specific embryologic mechanisms. Alimentary tract lesions were more common in Down syndrome than among euploid patients with heart disease and more severe than in control subjects. Urinary tract lesions also occurred in excess of the rate in control subjects. The coexistence of these major malformations with heart disease raises the possibility of incomplete expression of the VA(C)TER (vertebral, anal, cardiac, tracheal, esophageal renal) association. The selective association of chromosome abnormalities with certain cardiovascular defects is now beginning to be explained by reported embryologic studies on cellular characteristics. An explanation of the negative association with transposition and obstructive lesions requires further multidisciplinary studies on genetic and epigenetic factors.

Twenty-four-hour ambulatory blood pressure in normotensive adolescent children of hypertensive and normotensive parents

Twenty-four-hour ambulatory blood pressure measurements were obtained during usual daily activities from two groups of normotensive adolescents: Cases had at least one hypertensive parent, and controls had both parents normotensive. Automatic measurements were programmed at 7.5-minute intervals. For each subject, within each of three time periods, the data were summarized by descriptors of the frequency distribution and the frequency spectrum. The time periods were sleep, school hours, and other waking hours. Regression analyses examined the relation between the blood pressure monitoring descriptors and case-control status adjusted for non-blood-pressure variables found to relate to case-control status. In stepwise logistic regression analysis with case-control status as the dependent variable, it was found that the mean level of diastolic pressure during school hours was significant, whereas the standard resting measurement was not. In linear regression analyses with blood pressure monitoring descriptors and standard resting measurements as dependent variables, several monitoring descriptors were found to be significantly related to the interaction between case-control status and certain variables that can affect blood pressure, such as weight and the presumed stress of school; no such relations were found for the standard resting measurements. These findings demonstrate the superiority of the ambulatory monitoring variables over the standard resting measurements in studying case-control differences.

Assessing familial aggregation of congenital cardiovascular malformations in case-control studies

Recent data indicate that the familial aggregation of congenital cardiovascular malformations (CCVM) varies with the type of defect in the index case. Using a logistic regression model that allows for dependence among family members, we calculated the risk of any CCVM to case relatives compared with relatives of controls. Data from 3,908 first-degree relatives of 570 matched cases and controls identified from 1981 through 1985 by the Baltimore-Washington Infant Study were used in the analyses. Overall risk for any CCVM in case relatives was increased four-fold over that of control relatives. While relatives of cases with flow lesions (including right and left heart defects, as well as perimembranous ventricular septal defect [VSD]) had a five-fold increase in risk, the risk to relatives of nonflow lesion cases did not differ significantly from the risk to relatives of controls. Sex, maternal age, miscarriage history in the mother, and birth order had no apparent effect on risk among siblings. However, there was an indication of increased risk in relatives of nonwhite cases with VSD compared to relatives of matched controls. However, with these data it was not possible to distinguish between environmental and genetic sources of this familial aggregation.

Early detection of congenital cardiovascular malformations in infancy

In an ongoing population-based study of congenital cardiovascular malformations in the Baltimore-Washington, DC, area, 1527 affected infants were ascertained from multiple sources during the years 1981 to 1984. Ninety-eight percent were evaluated at a regional pediatric cardiology center. Among the unreferred cases, in which the cardiac defect was diagnosed only at autopsy, most infants died in the first week of life and had associated problems, such as low birth weight, major noncardiac malformations, or other life-threatening illnesses, but a few infants with potentially remediable heart disease escaped clinical detection. Until preventive measures become available, reduction of infant mortality due to congenital cardiovascular malformations will continue to depend on early recognition of signs of serious heart disease in infants and on effective community-wide use of specialized cardiac services.

Changes in alcohol, cigarette, and recreational drug use during pregnancy: implications for intervention

From the Baltimore-Washington Infant Study, a regional epidemiologic study of congenital cardiovascular malformations, 1,336 mothers of infants selected as controls (a representative sample of the area birth cohort enrolled between April 1, 1981 and September 1, 1984) were studied with respect to alcohol, cigarette, and recreational drug use prior to and during pregnancy. Nearly half of the 1,336 women abstained from any substance use during pregnancy. Of the remainder, half restricted substance use to only alcohol or cigarettes. Only cigarette smokers showed a majority (68.5%) of women failing to successfully quit during pregnancy. Cigarette and recreational drug use during pregnancy was associated with lower socioeconomic status, while alcohol use was associated with higher social status. Cessation of cigarette and recreational drug use was more common among professionals and the college-educated, but these same characteristics, along with higher income, were associated with failure to quit drinking. Younger women were less likely to use alcohol and cigarettes and more likely to successfully quit these habits once adopted. Use of alcohol and tobacco was greater among whites, and recreational drug use was greater among black women, but race was not associated with quitting use of any substance. Length of time trying to become pregnant and the mother's perceived health were not found to be associated with substance use or quitting. This sociodemographic profile suggests subgroups which must be targeted for intervention by the prenatal care provider, as well as intervention strategies.

Cardiac and noncardiac malformations: observations in a population-based study

A regional case-control study of congenital cardiovascular malformations (CCVMs) searches for all live-born infants in the community in whom the cardiac diagnosis has been confirmed by echocardiography, cardiac catheterization, surgery, or autopsy. Their families are studied in comparison to those of a representative sample of resident live-born infants. Detailed descriptions of noncardiac abnormalities are obtained from physician reports and maternal interviews expanded by medical record and death certificate data. Among 1,494 cases and 1,572 controls, chromosomal abnormalities, syndromes, heritable disorders, and suspect syndromes occurred with an overwhelming excess in cases (chromosomes, P less than 10(-4); syndromes/heritable disorders, P less than .005). Abnormalities affecting chromosomes 13, 18, and 21 constituted 93% of the cytogenetic defects. Syndromes and heritable disorders were of 39 types. Nonsyndromic abnormalities were three times more frequent in cases than in controls (P less than .005). Case excesses occurred for central nervous system malformations, eye disorders, major abdominal wall defects, and abnormalities of the alimentary and urinary tracts. Severe anomalies frequent among cases were those which also occur in certain recognized syndromes, and it is suggested that paired combinations of cardiac and other midline anomalies may represent "formes frustes" of syndromes with similar though variable phenotypic expressions. Cleft lip and palate, inguinal hernia, and lower limb anomalies occurred with equal frequency, suggesting their association with CCVMs by chance alone.

Familial risks of congenital heart defect assessed in a population-based epidemiologic study

Congenital heart defects (CHD) represent a heterogeneous group of disorders caused by chromosome abnormalities, mendelian disorders, teratogenic exposures, and unknown etiologic mechanisms. A large group of various isolated defects is presumably multifactorial in origin. Previous studies of familial risks for specific anatomic defects obtained from clinical series may include significant biases and obscured pathogenic relationships. In this population-based study we analyzed all cases of CHD in infants and a control birth cohort in the Baltimore-Washington area. The rates of CHD were defined for first-degree relatives of cases with isolated defects, grouped by a pathogenic classification scheme. Precurrence risks were found to vary among the groups, and risks for flow lesions were higher than previously reported. The sibling precurrence risk for hypoplastic left heart syndrome (13.5%) was not significantly different from that expected for an autosomal recessive mechanism; the risks for different types of ventricular septal defects (VSD) varied among mechanistic groups. The results indicate that the additive multifactorial model does not adequately account for the risks in all forms of isolated CHD of unknown etiology.

Physician-patient communication. Understanding congenital heart disease

Mothers' descriptions of their childrens' congenital heart disease were compared with cardiologists' diagnoses. Maternal understanding was examined with respect to 21 factors using bivariate contingency tables and multiple regression analyses. Of 285 mothers, 36% demonstrated poor comprehension. Maternal understanding was associated with sociodemographic variables but not with factors related to stress. All variables taken in concert that were predictive of understanding explained less than 13% of the variability in maternal knowledge. Distorted perceptions of congenital heart disease may cause unnecessary anxieties, inappropriate restrictions, and impairment of the child's self-perception. The bizarre nature of some of the mothers' incorrect descriptions and the accuracy of responses of mothers in biologic and health care occupations suggest that fundamental ignorance of the cardiovascular system may be of such importance as to minimize the impact of other variables.

Subsequent pregnancy in mothers of infants with congenital heart disease

Pregnancy rates for mothers of infants with conotruncal cardiac malformations and mothers of healthy control infants were compared for a 3-year period. Mothers of infants who died of congenital heart disease had the highest pregnancy rates, followed by control mothers, and then by mothers of surviving infants with congenital heart disease. Comparison in relation to the number of living children showed similar subsequent pregnancy rates for mothers of deceased infants with congenital heart disease and mothers of control infants, but lower rates for mothers of surviving infants with congenital heart disease. "Replacement" of a deceased infant occurs frequently, apparently in order to achieve a desired family size, whereas decreased reproduction in families of living infants with congenital heart disease may reflect the psychosocial and economic impact of the continuing care of a child with severe heart disease.

Congenital heart disease: prevalence at livebirth. The Baltimore-Washington Infant Study

The Baltimore-Washington Infant Study is a regional epidemiologic study of congenital heart disease. Among Infants born in the study area in 1981 and 1982, 664 had a diagnosis of congenital heart disease confirmed in the first year of life by echocardiography, cardiac catheterization, cardiac surgery, or autopsy. The prevalence rate was 3.7/1,000 livebirths for all cases and 2.4/1,000 livebirths for cases confirmed by invasive methods only. Diagnosis-specific prevalence rates of congenital heart disease are compared with those of eight previous case series. Changing diagnostic categorizations in the time span covered and methodological differences resulted in great variation of the data. However, the data of the New England Infant Cardiac Program which used the same case discovery methods showed similar occurrences of major morphologic abnormalities, suggesting that these are stable basic estimates in the eastern United States. For all case series, the rate of confirmed congenital heart disease was approximately 4/1,000 livebirths over the 40-year time span.

Maternal hormone therapy and congenital heart disease

Exogenous female sex hormone exposure was studied in the mothers of 110 infants with conotruncal malformations of the heart, born in the years 1972-75. Cases were ascertained throughout the referral area of the Maryland State Intensive Care Neonatal Program. For each case, three normal controls were chosen from the birth population: Two matched on eight characteristics related to the likelihood of hormone-taking (race, maternal age, parity, fetal losses, gestational age, delivery mode, time of prenatal registration, private/service), and one also on the infant's sex and birthweight; the third control was chosen at random. In personal interviews, information was obtained on the mother's general health, family history, reproductive characteristics, pregnancy health, and environmental exposures. Identification of hormonal products was aided by a display of pills and packages. Maternal recall was examined in comparison to the responses of a group of mothers of infants with hypoplastic left heart ("disease controls"). Regression analysis on time elapsed since the infant's birth revealed no difference in recall between the mothers of cases and of controls. Multilogistic regression analysis, controlling for confounding variables and for scores constructed for reproductive, malformation, and exposure risks, showed no increase in relative risk for cases when compared with matched controls. When compared to random controls, the analysis suggested a possible increase in relative risk with increased environmental exposure scores; components of the risk score were excess smoking and alcohol intake, exposure to X-ray, drugs, paints, insecticides, and chemicals. The possible significance of this finding needs to be further investigated.