Infant mortality and congenital anomalies from 1950 to 1994: an international perspective

STUDY OBJECTIVE

To provide an international perspective on the impact of congenital anomalies on infant mortality from 1950 to 1994.

DESIGN

Population-based study based on data obtained from vital statistics reported to the World Health Organisation.

SETTINGS

36 countries from Europe, the Middle East, the Americas, Asia, and the South Pacific.

RESULTS

On average, infant mortality declined 68.8 per cent from 1950 to 1994. In the countries studied, infant mortality attributable to congenital anomalies decreased by 33.4 per cent, although it recently increased in some countries in Central and Latin America and in Eastern Europe. Anomalies of the heart and of the central nervous system accounted for 48.9 per cent of infant deaths attributable to congenital anomalies. During 1990-1994, infant mortality attributable to congenital anomalies was inversely correlated to the per capita gross domestic product in the countries studied. At the same time, the proportion of infant deaths attributable to congenital malformations was directly correlated with the per capita gross domestic product.

CONCLUSIONS

Congenital malformations account for an increasing proportion of infant deaths in both developed and developing countries. Infant mortality attributable to congenital anomalies is higher in poorer countries although as a proportion of infant deaths it is greater in wealthier countries. Conditions such as spina bifida, whose occurrence can be reduced through preventive strategies, still cause many infant deaths. The apparent increase of infant mortality because of congenital anomalies in some countries should be investigated to confirm the finding, find the causes, and provide prevention opportunities.

Limb defects associated with major congenital anomalies: clinical and epidemiological study from the International Clearinghouse for Birth Defects Monitoring Systems

Although limb defects associated with other congenital anomalies are rarely studied, they may provide insights into limb development that may be useful for etiologic studies and public health monitoring. We pooled data from 11 birth defect registries that are part of the International Clearinghouse for Birth Defects Monitoring Systems. We identified 666 infants, born from 1983 through 1993, who had a non-syndromal limb defect plus at least one other major malformation (rate 12.9/100,000 population). We used observed/expected ratios and log-linear models to detect association patterns. We found that specific limb defects occurred with relatively distinct sets of malformations. Preaxial limb defects occurred more frequently with microtia, esophageal atresia, anorectal atresia, heart defects, unilateral kidney dysgenesis, and some axial skeleton defects; postaxial defects with hypospadias; transverse defects with craniofacial defects, micrognathia, ring constrictions, and muscular defects; intercalary defects with omphalocele; split hand/foot with encephalocele; and amelia with anorectal atresia, omphalocele, severe genitalia defects, unilateral kidney dysgenesis, gastroschisis, and ring constriction. Log-linear modeling identified higher order associations among some of these same malformations.

OEIS complex--a population study

Using a novel method for the analysis of infants with multiple malformations, we investigated the cluster of associated malformations called the OEIS (omphalocele, bladder exstrophy, imperforate anus, spine defect) complex among 5,260 infants with multiple malformations identified in four large registers of congenital malformations, corresponding to 5.84 million births. The existence of the OEIS complex was clearly demonstrated and malformations entering it could be defined. Other than the four classical malformations, omphalocele, bladder exstrophy, imperforate anus, and spine malformation, a strong association with spina bifida and intersex was stressed. Spine malformations occurred not only in the lumbosacral level but also more cranially, and an association also with upper spina bifida could be demonstrated. No specific association with any other malformation, including cardiac defects, was apparent. The OEIS complex is an unusually clearly defined entity among the various nonrandom associations which have been described.

Prospective, controlled, multicentre study of loperamide in pregnancy

BACKGROUND

Loperamide is a synthetic piperidine derivative used for the treatment of both acute and chronic diarrhea. Little is known about its safety and risk in pregnancy. Human data are limited to one surveillance study of Michigan Medicaid patients, with 108 women exposed in the first trimester. In this study there were six major birth defects, three of which were cardiovascular anomalies.

OBJECTIVES

To determine whether loperamide use in pregnancy is associated with an increased risk of major malformations. The secondary end points were rates of minor malformations, spontaneous and therapeutic abortions, and premature births, and mean birth weights.

PATIENTS AND METHODS

Women counselled by five teratogen information centres on the safety and risk of loperamide in pregnancy were followed after delivery and compared with a similar group of women matched for age, smoking, alcohol and other exposures.

RESULTS

One hundred and five follow-ups were completed; 89 of the women were exposed to loperamide in the first trimester of pregnancy. There were no statistically significant differences between the study group and the control group in any of the end points that were analyzed. However, of women who took loperamide throughout their pregnancy, 21 of 105 had babies who were 200 g smaller than babies in the control group.

CONCLUSIONS

The results of this study suggest that the use of loperamide during pregnancy is not associated with an increased risk of major malformations.

Growth and developmental retardation, ocular ptosis, cardiac defect, and anal atresia: confirmation of the ROCA-Wiedemann syndrome

We report on a girl with growth and mental retardation, peculiar face with ptosis, epicanthus, broad nasal bridge, low-set and abnormal ears, cleft uvula, congenital heart defect, and anal atresia. A similar condition was reported previously by Wiedemann et al. [1982: An atlas of characteristic syndromes: a visual aid to diagnosis, 2nd ed. p 114-115]. We confirm the existence of this condition that, although similar to Ohdo syndrome, seems to be an independent clinical entity. We propose that, based on the principal clinical manifestations, this condition should be identified with the acronym ROCA (retardation of growth and development, ocular ptosis, cardiac defect, and anal atresia).

CHARGE Association in newborns: a registry-based study

The CHARGE Association is a nonrandom occurrence of congenital malformations that has been described in clinical series. Reported patients have been selected on the basis of certain prior criteria. In this article, we try to identify a congenital malformation pattern corresponding to the CHARGE Association, using statistical methods and analyzing 5,260 infants with multiple malformations collected from four large registries of congenital malformations. Care was taken to identify a number of confounding characteristics that can influence the ascertainment and registration of specific congenital malformations. We have identified a cluster of malformations that generally agreed with the current clinical definition of the CHARGE Association and have added some further malformations (e.g., facial clefts). We demonstrate that others (e.g. , esophageal atresia) are probably not part of the pattern. Heart defects (H in the acronym) seems to be less helpful in identifying infants with the association. We suggest a method to select infants who probably represent the CHARGE Association for analyses of possible risk factors.

A modified method for the epidemiological analysis of registry data on infants with multiple malformations

BACKGROUND

Infants with multiple malformations are important in birth defect epidemiology and malformation monitoring because human teratogens have often caused complex malformations. Various methods for the analysis of multimalformed infants have been tried.

METHOD

By using data from four large registries of congenital malformations, 5256 infants were identified with two or more among 73 selected malformations. Pairwise associations between malformations were detected by multiple logistic regression analyses, and putative confounders (programme, maternal age, autopsy, etc.) were controlled for. For each significant pairwise association, further analyses were performed in order to find associations with a possible third malformation.

RESULTS

The importance of controlling for several confounders was demonstrated. Several well-known associations were found, which supports the technique used. The interpretation of three-way associations was discussed. Results from the present study were compared with those obtained using some other methods.

CONCLUSIONS

Different confounders can cause biased associations. The method presented in the paper takes this into consideration and is therefore more likely than previously used techniques to give unbiased information on the clustering of different malformations among multimalformed infants.

Congenital malformations in twins: an international study

Data provided by nine registries based in European and Latin America countries were analyzed to assess whether there is an excess of malformations in twins compared to singletons. Specific congenital malformations were coded according to the ninth revision of the International Classification of Diseases (ICD). Malformation rates and rate ratios (RR) for twins compared to singletons were calculated for each registry, and the homogeneity of the RRs was tested using the test of Breslow and Day. If departure from homogeneity in the different registries was not significant, registry-adjusted RRs with 95% confidence intervals were calculated. Overall, among 260,865 twins, 5,572 malformations were reported. A total of 101 different types of malformations or groups of defects was identified, and a homogeneous estimate of the RRs among registries was found for 91.1% of the malformations. Thirty-nine of the 92 malformations with homogeneous estimates of RRs were more common in twins than in singletons. For the remaining nine malformations, heterogeneous estimates of RRs were obtained. This study confirms the majority of already known associations and further identifies previously unreported malformations associated with twins. In conclusion, there is an excess of malformations in twins compared with singletons, and all anatomical sites are involved. The number of specific malformations associated with twins is higher than that previously reported in smaller studies.

High vitamin A intake in early pregnancy and major malformations: a multicenter prospective controlled study

The European Network of the Teratology Information Services (ENTIS) collected and evaluated data on 423 pregnancies exposed during the first 9 weeks of gestation to a "high" dose of vitamin A (10,000 IU per day or more). Data were collected prospectively; 394 women (93.1%) were followed by telephone interview up to the first few weeks after the expected date of delivery, using standardized procedures. The presence of major structural malformations, excluding chromosomal and genetic diseases, was evaluated in 311 infants exposed to a median daily dose of vitamin A of 50,000 IU per day (range, 10,000-300,000 IU per day; interquartile range, 25,000-60,000 IU per day). Three infants with a major malformation were reported: pulmonary stenosis, stenotic anus with fistula, and bilateral inguinal hernia. No congenital malformations were reported among 120 infants exposed to more than 50,000 IU per day of vitamin A. When the birth prevalence rate of major malformations in the study group was compared with two internal control groups of infants exposed to: 1) "high" vitamin A exposure later in pregnancy, and 2) nonteratogenic agent exposures, the rate ratio was, respectively, 0.28 (CI 95% interval, 0.06, 1.23) and 0.50 (CI 95% interval, 0.14, 1.76). The studied sample did not provide evidence for an increased risk of major malformations, associated with "high" vitamin A intake during the organogenetic period, higher than 2.76 above the control reference risk of 1.91% (power 80%, alpha 0.10).

The C677T mutation of the 5,10-methylenetetrahydrofolate reductase gene is a moderate risk factor for spina bifida in Italy

OBJECTIVE

To estimate the risk for spina bifida associated with the common mutation C677T of the MTHFR gene in a country with a relatively low prevalence of NTDs.

DESIGN

Case-control study.

SUBJECTS

CASES

203 living patients affected with spina bifida (173 myelomeningocele and 30 lipomeningocele); controls: 583 subjects (306 young adults and 277 unselected newborns) from northern and central-southern Italy.

SETTING

CASES

three spina bifida centres; young adult controls: DNA banks; newborn controls: regional neonatal screening centres.

MAIN OUTCOME MEASURES

Prevalence of the C677T genotypes in cases and controls by place of birth; odds ratios for spina bifida and estimated attributable fraction.

RESULTS

The prevalence of T/T, T/C, and C/C genotype was 16.6%, 53.7%, and 29.7% in controls and 25.6%, 43.8%, and 30.6% in cases, respectively. We found no differences between type of defect or place of birth. The odds ratio for spina bifida associated with the T/T genotype v C/C plus T/C was 1.73 (95% CI 1.15, 2.59) and the corresponding attributable fraction was 10.8%. No increased risk was found for heterozygous patients (OR=0.79, 95% CI 0.53-1.18).

CONCLUSION

This study, as well as the meta-analysis we updated, shows that homozygosity for the MTHFR C677T mutation is a moderate risk factor in Europe, and even in Italy where there is a relatively low prevalence of spina bifida. The estimated attributable fraction associated with this risk factor explains only a small proportion of cases preventable by periconceptional folic acid supplementation. Thus, other genes involved in folate-homocysteine metabolism, their interaction, and the interaction between genetic and environmental factors should be investigated further.

The safety of omeprazole during pregnancy: a multicenter prospective controlled study

OBJECTIVES

Our purpose was to determine whether omeprazole use during pregnancy is associated with an increased risk of malformations, spontaneous abortions, decreased birth weight, or perinatal complications.

STUDY DESIGN

In a multicenter, prospective controlled study, pregnant women exposed to omeprazole during gestation were matched with controls exposed to nonteratogens and with disease-paired controls who used histamine blockers for similar indications. The primary end point was the incidence of major malformations.

RESULTS

One hundred thirteen pregnant women were exposed to omeprazole during pregnancy. Rates of major malformations in the omeprazole group (4%) did not differ from controls exposed to nonteratogens (2%) (P = .68, relative risk = 1.94, 95% confidence interval 0.36 to 10.36) and disease-paired controls (2.8%). Birth weight, gestational age at delivery, preterm deliveries, and neonatal complications were comparable among the three groups.

CONCLUSIONS

No association was found between exposure to omeprazole during the period of organogenesis and increased risk for major malformations. Exposure throughout pregnancy is not associated with increased risk of spontaneous abortions, decreased birth weight, or perinatal complications.

Exploring gene-gene interactions in the etiology of neural tube defects

The role of susceptibility genes in the etiology of birth defects is unclear, but may involve in some cases multiple alleles at multiple loci. We suggest a simple epidemiologic approach to explore gene-gene interactions, and use it to reevaluate data from a recent case-control study on the possible association of neural tube defects (NTDs) with specific mutations of two genes, 5,10-methylene-tetrahydrofolate reductase (MTHFR) and cystathionine-beta synthase (CBS). We found that, compared with the common genotype, homozygosity for the MTHFR mutation alone was associated with a two-fold increased risk for NTDs, while homozygosity for the CBS mutation alone was not a risk factor. However, homozygous individuals for the mutations at both loci had a five-fold greater risk for NTDs than those with the reference genotype. Though the original study was too small to detect statistically significant differences among most of the risk estimates, these results, if confirmed by independent and larger studies, suggest that gene-gene interaction may play a role in modulating the susceptibility to NTDs in a proportion of affected individuals. This approach, moreover, could be a valuable adjunct to the study of gene gene interactions in the etiology of human disease.

Birth weight discordancy in twins: new definition and standard

OBJECTIVE

The aim of this study was to improve the definition of birth weight discordancy based on its distribution in the population after a correction in the unlike sex pairs.

STUDY DESIGN

The analysis was conducted on 849 Italian twin pairs. Male's birth weight in the unlike sex pairs was corrected by the physiological birth weight difference estimated on 21.595 Italian twins data. Birth weight discordancy was computed as a percentage of the larger twin's birth weight and it was compared by sex pairs and by gestational ages (Kruskal-Wallis test). Kolmogorov-Smirnov test was used to fit a normal distribution to the square-root transformed birth weight discordancy.

RESULTS

The estimated physiological birth weight difference between males and females was 4.39%, without any difference among gestational ages. The 90th centile of birth weight discordancy was 23.9% and the 95th centile was 29.2%.

CONCLUSIONS

Ninetieth and 95th centiles of the fitted distribution are proposed as cut-off values for the definition of mild and severe birth weight discordancy.

Opitz C trigonocephaly syndrome and midline brain anomalies

We describe a child with trigonocephaly, strabismus, upslanting palpebral fissures, nasal bridge hypoplasia, hypertrophic alveolar ridges and large gingivo-labial frenula, short neck, hip "dysplasia," equinovarus deformities, cryptorchidism, atrial septal defect ostium secundum, and severe mental retardation, findings consistent with C syndrome. The patient also had a Dandy-Walker malformation, complete callosal agenesis, and occipital meningocele. These structural defects are independent of the premature closure of the metopic suture, and confirm that midline brain anomalies are part of C syndrome. The hypothesis that the basic developmental defect in this syndrome primarily affects the midline field is supported by the concomitance of other anomalies, such as conotruncal heart defects, omphalocele, and genital anomalies.

Cisapride use during human pregnancy: a prospective, controlled multicenter study

The objective of this prospective multicenter study was to determine whether cisapride is associated with increased risk of malformations, spontaneous abortions, or decreased birthweight when used during pregnancy. Cases were paired for age, smoking, and alcohol consumption with controls exposed to nonteratogens, as well as with disease-paired controls. One hundred and twenty-nine pregnant women were exposed to cisapride during pregnancy, including 88 during the period of fetal organogenesis. There were no differences in maternal history, birthweight, gestational age at delivery, and rates of livebirths, spontaneous or therapeutic abortions, fetal distress, and major or minor malformations among groups. It is concluded that exposure to cisapride during pregnancy is not associated with a major increased risk of malformations or spontaneous abortions or with decreased birthweight.

The spectrum of congenital anomalies of the VATER association: an international study

The spectrum of the VATER association has been debated ever since its description more than two decades ago. To assess the spectrum of congenital anomalies associated with VATER while minimizing the distortions due to small samples and referral patterns typical of clinical series, we studied infants with VATER association reported to the combined registry of infants with multiple congenital anomalies from 17 birth defects registries worldwide that are part of the International Clearinghouse for Birth Defects Monitoring Systems (ICB-DMS). Among approximately 10 million infants born from 1983 through 1991, the ICB-DMS registered 2,295 infants with 3 or more of 25 unrelated major congenital anomalies of unknown cause. Of these infants, 286 had the VATER association, defined as at least three of the five VATER anomalies (vertebral defects, anal atresia, esophageal atresia, renal defects, and radial-ray limb deficiency), when we expected 219 (P<0.001). Of these 286 infants, 51 had at least four VATER anomalies, and 8 had all five anomalies. We found that preaxial but not other limb anomalies were significantly associated with any combination of the four nonlimb VATER anomalies (P<0.001). Of the 286 infants with VATER association, 214 (74.8%) had additional defects. Genital defects, cardiovascular anomalies, and small intestinal atresias were positively associated with VATER association (P<0.001). Infants with VATER association that included both renal anomalies and anorectal atresia were significantly more likely to have genital defects. Finally, a subset of infants with VATER association also had defects described in other associations, including diaphragmatic defects, oral clefts, bladder exstrophy, omphalocele, and neural tube defects. These results offer evidence for the specificity of the VATER association, suggest the existence of distinct subsets within the association, and raise the question of a common pathway for patterns of VATER and other types of defects in at least a subset of infants with multiple congenital anomalies.

Randomised controlled trial assessing the effectiveness of a booklet on the duration of breast feeding

OBJECTIVE

To test the efficacy of an information booklet to increase the duration of breast feeding.

RESEARCH DESIGN

Randomised design, stratifying by maternal residence and working activity. Two hundred women were recruited, 103 received the booklet and verbal counselling and 97 verbal counselling only.

POPULATION

Infants observed from 15 September 1993 to 15 June 1994 in the well baby outpatient clinic of the Paediatric Institute of the Catholic University of Rome, Italy.

MAIN RESULTS

No statistically significant difference was found between the two groups in the prevalence of exclusive or complementary breast feeding at 6 months of age: 48.5% and 59.2% in the intervention group, 43.7% and 51.5% in the control group. The median duration of exclusive or complementary breast feeding was 24 and 27 weeks in the treated group, 22 and 25 in the control group.

CONCLUSIONS

The information booklet alone does not seem to increase the duration and the prevalence of breast feeding at 6 months of age. The use of written material with a more individualised support and more extensive use of randomised clinical trials in the evaluation of health promoting programmes is recommended.

Prospective assessment of pregnancy outcomes after first-trimester exposure to fluconazole

OBJECTIVE

Our purpose was to study prospectively the pregnancy outcome after first-trimester exposure to fluconazole, an effective antifungal agent teratogenic in animals.

STUDY DESIGN

We conducted a prospective cohort study of women who contacted three Italian teratogen information services. We compared the pregnancy outcomes of 226 women exposed to fluconazole with that of 452 women exposed to nonteratogenic agents, with use of logistic regression to control for potential confounders.

RESULTS

Among the 226 pregnancies exposed to fluconazole there were 22 miscarriages, 1 stillbirth, and 7 infants with congenital anomalies. The prevalence of these outcomes and of neonatal growth parameters and the rate of neonatal complications were similar to those in the reference group. Women in the fluconazole group had a fivefold increased occurrence of induced abortions.

CONCLUSIONS

First-trimester exposure to fluconazole does not appear to increase the prevalence of miscarriages, congenital anomalies, and low birth weight.

Major congenital malformations in Down syndrome

We studied major malformations in 5,581 infants with Down syndrome (DS) from three registers of congenital malformations. THe prevalence at birth of 23 different malformations was compared with the program-specific rates for each malformation in non-DS infants. An about 300 times risk increase was seen for annular pancreas, cataracts and duodenal atresia and an about 100 times risk increase for megacolon and small choanal atresia. Esophageal, anal and small bowel atresia, preaxial polydactyly, and omphalocele all showed risk increases between 10 and 30 times. Statistically significantly elevated risk ratios around 3-5 were seen for cleft palate, cleft lip/palate, and limb deficiencies. No increased risk was seen for neural tube defects, hydrocephaly, microtia, renal agenesis or severe dysgenesis, hypospadias or polydactyly other than preaxial. Oral clefts were more often present in DS in the Swedish material than in the other two materials. Cardiac defects were registered in 26% of all cases (varying between programs) but 28% of the cardiac defects were unspecified. DS infants born to women younger than 25 years had a significantly increased risk for megacolon and there was a trend increasing risk for esophageal or anal atresia with maternal age. A decreased risk for cardiac defect in DS infants born to teenage mothers was found, quite pronounced for endocardial cushion defects and ventricular septum defects. There were no statistically significant differences in the sex distribution of specific malformations in infants with DS and in non-DS infants.

The Williams syndrome: an Italian collaborative study

Williams syndrome (WS) is a multiple congenital anomalies/mental retardation syndrome caused by a microdeletion on the long arm of chromoome 7 including the elastin gene. Possibly it is a contiguous gene syndrome with autosomal dominant transmission. Seventy-seven WS patients from 11 Italian Pediatric-Dysmorphology-Genetics Units were collected by means of a questionnaire designed to draw a comprehensive clinical picture, to define the frequency of different traits and associations thereof, to better understand the clinical evolution, to improve the prognosis and to ameliorate the follow-up. The most important signs for diagnosis, based on their relative frequencies, are: mental retardation with characteristic outgoing behaviour and hoarse voice; facial findings like stellate iris, periorbital fullness and thick lips; congenital heart disease. The frequency of the clinical signs reported in our patients are on the whole concordant with those found in the literature; the only significant differences concern low stature, hallus valgus, hypoplastic nails, joint contractures and ear infections. The multisystemic nature of this syndrome requires a coordinated and integrated approach in order to avoid fragmentary interventions.