Trends in the prevalence, risk and pregnancy outcome of multiple births with congenital anomaly: a registry-based study in 14 European countries 1984-2007.

OBJECTIVE: To assess the public health consequences of the rise in multiple births with respect to congenital anomalies. DESIGN: Descriptive epidemiological analysis of data from population-based congenital anomaly registries. SETTING: Fourteen European countries. POPULATION: A total of 5.4 million births 1984-2007, of which 3% were multiple births. METHODS: Cases of congenital anomaly included live births, fetal deaths from 20 weeks of gestation and terminations of pregnancy for fetal anomaly. MAIN OUTCOME MEASURES: Prevalence rates per 10,000 births and relative risk of congenital anomaly in multiple versus singleton births (1984-2007); proportion prenatally diagnosed, proportion by pregnancy outcome (2000-07). Proportion of pairs where both co-twins were cases. RESULTS: Prevalence of congenital anomalies from multiple births increased from 5.9 (1984-87) to 10.7 per 10,000 births (2004-07). Relative risk of nonchromosomal anomaly in multiple births was 1.35 (95% CI 1.31-1.39), increasing over time, and of chromosomal anomalies was 0.72 (95% CI 0.65-0.80), decreasing over time. In 11.4% of affected twin pairs both babies had congenital anomalies (2000-07). The prenatal diagnosis rate was similar for multiple and singleton pregnancies. Cases from multiple pregnancies were less likely to be terminations of pregnancy for fetal anomaly, odds ratio 0.41 (95% CI 0.35-0.48) and more likely to be stillbirths and neonatal deaths. CONCLUSIONS: The increase in babies who are both from a multiple pregnancy and affected by a congenital anomaly has implications for prenatal and postnatal service provision. The contribution of assisted reproductive technologies to the increase in risk needs further research. The deficit of chromosomal anomalies among multiple births has relevance for prenatal risk counselling.

Effects of genetic vs. environmental factors on cardiovascular autonomic function: a twin study.

AIMS: Cardiovascular autonomic function is often assessed in patients with diabetes by measuring heart rate variability and baroreflex sensitivity, the heritability of which is not fully understood. The present study was aimed to determine the effects of genetic and environmental factors on heart rate variability and baroreflex sensitivity in monozygotic and dizygotic adult healthy twin pairs. METHODS: A total of 101 (63 monozygotic, 38 dizygotic) adult twin pairs (n = 202; mean age 44.3 years) were investigated. Anthropometric variables and serum metabolic markers were measured, while environmental characteristics were evaluated by questionnaires. Linear and spectral indices of heart rate variability and baroreflex sensitivity were determined by non-invasive methods. All measurements were adjusted for age and gender (model 1) and for all significantly relevant covariates (model 2). Heritability A-C-E structural equation models were used for characterizing the proportion of additive genetic, shared and unshared environmental influences. RESULTS: Genetic influence of different cardiovascular autonomic indices was estimated between 10.3 and 39.4%, common environmental influence was found between 0.0 and 33.2%, while unshared environmental influence was observed between 60.6 and 81.4% in model 1 analysis. In multivariable-adjusted heritability estimates (model 2), the magnitude of the genetic effects decreased to 0.0%, common environmental influence was nearly unchanged (values between 4.4 and 14.5%), while unshared environmental influence slightly increased (values between 85.5 and 96.5%). CONCLUSIONS: Unshared environmental but not genetic factors have substantial influence on cardiovascular autonomic function, suggesting that appropriate treatment of all modifiable environmental factors is of importance in order to prevent or ameliorate cardiovascular autonomic neuropathy.

Maternal employment status and isolated orofacial clefts in Hungary.

AIMS: To study the role of maternal employment status as indicator of socioeconomic status in the origin of isolated orofacial clefts (OFC) and in the use of periconceptional folic acid/multivitamin supplementation. METHODS: 1,975 cases with OFC (1,374 cases with cleft lip +/- palate and 601 cases with posterior cleft palate), 38,151 population controls without any defects and 20,868 patient controls with other isolated defects were compared in the population-based data set of the Hungarian Case-Control Surveillance of Congenital Abnormalities (HCCSCA), 1980-1996. RESULTS: The proportion of professionals and managerials was lower, while the proportion of unskilled workers, housewives and others was higher in the mothers of cases with OFC compared with the population control group. However, the comparison of OFC and patient control groups did not show any difference in the employment status of mothers. A lower level of folic acid supplementation occurred in the professional and skilled worker mothers of cases with OFC compared with the population control group. This difference was confirmed by the comparison of folic acid used by mothers of cases with OFC compared with patient controls. An infrequent multivitamin use was displayed in the studied groups. CONCLUSIONS: The prevalence of OFC at birth shows a slightly lower maternal employment status as indicator of socioeconomic status than in the population control group. The higher level of maternal education does not imply a higher rate of folic acid supplementation in the group of OFC.

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.

The effect of preconceptional multivitamin supplementation on fertility.

A significantly higher rate of conceptions occurred after preconceptional multivitamin supplementation in comparison with a placebo-like trace element supplementation in the Hungarian randomised, double-blind, controlled trial. This difference was explained by 5% shorter time in the achievement of conception.

[Prevalence of severe visual impairement in school-age children in Hungary]. / Az iskoláskorú súlyos látási fogyatékos gyermekek gyakorisága Magyarországon.

The recorded prevalence of 6 to 14 year-old children with severe visual handicap was 0.43 per 1000 in Hungary, 1983/84. The territorial distribution showed significant difference in prevalences, the highest figures were found in two entities with three special institutions for severely visually handicapped children. Thus, the recorded figures are underascertained and the estimated rates are 0.52-0.60 and 0.21 per 1000 for children with severe visual handicap and, within it, blindness, respectively.

[Peri-conceptional multivitamin administration may result in higher frequency of twin pregnancies]. / Multivitamin periconceptionalis adását követóen észlelt nagyobb ikergyakoriság.

A randomized controlled trial of periconceptional multivitamin supplementation including 0.8 mg folic acid was carried out for at least 28 days before conception. The trial was continued until at least until the second missed menstrual period to test the effectiveness of this new primary preventive method in the reduction of neural tube defects. However, other pregnancy outcomes were also evaluated. Of total of 5,502 pregnant women, 4,846 births were analysed in the final data base. The rate of multiple births was significantly higher in the multivitamin group (3.8%) than in the placebo-like trace-element control group (2.7%), and in both groups exceeded the multiple birth rate of 2.2% of women in the Hungarian population at large. 7.3% of women in the multivitamin and 7.9% of women in the trace-element groups received ovarian stimulation treatment (mainly clomiphen) for hormonal dysfunctions, e.g. anovulation. Nonetheless, our study showed that periconceptional multivitamin supplementation, with or without stimulation, increases the rate of multiple births.

[Comparative study of the consumption of cariogenic food in monozygotic and same-sex dizygotic twins]. / Monozygota és azonos nemü dizygota ikrek cariogen élelmiszer fogyasztási frekvenciáinak összehasonlító vizsgálata.

The eating habits of the 111 monozygotic and 67 like-sexed dizygotic twins were compared with respect to cariogenic foods. The food habits were recorded using a seven-day dietary history with the weekly frequency of the cariogenic foods examined. The biometrical analysis showed that the eating habits of the monozygotic pairs were more similar than that of the dizygotic twin pairs. The differences were statistically significant. Based on these findings, it seems that genetic factors play a role in the development of the food habits.

Evaluation of counselling for pregnant women exposed to potentially hazardous environmental factors.

Pregnancy outcomes of 546 women seeking advice for exposure to suspected dangerous environmental factors during pregnancy were analysed. Induced abortion was recommended to 58 women, and this advice was followed by 55 of them. An additional 24 pregnancies were interrupted. The rates of fetal death (spontaneous abortion, stillbirth and infant death) in the non-terminated pregnancies corresponded to national figures. The proportion of birth defects among the liveborn infants of women exposed to hazardous physical, chemical, microbial and maternal factors was 5/67 (7.5%), 11/120 (9.2%), 6/158 (3.8%) and 1/22 (4.5%), respectively. These figures did not differ significantly from the expected ones based on the Hungarian registered and estimated figures. Furthermore, a causal relation between the environmental factors and the defects could be excluded in all but one case in which there was exposure to a high dose of oestrogen.

Recurrence risk after neural tube defects in a genetic counselling clinic.

The recurrence of isolated neural tube defects in a population of women from a genetic counselling clinic was found to be 3.4%. After one baby with a neural tube defect the recurrence was 2.3%. Of the 15 pregnancies of women who had two previous babies with neural tube defects, there were three further recurrences. These findings show that the Hungarian recurrence risk of isolated neural tube defects has not changed with a declining birth prevalence, and that the rate in genetic counselling clinic patients is the same as in a previous population based epidemiological study.

Conjoined twins in Hungary, 1970-1986.

The total prevalence of conjoined twins (birth + prenatally diagnosed) was 1:68,000 in the study of 1970-1986. Symmetrical cases (the so-called siamese twins) have an obvious predominance (92.3%). Associated major malformations occurred in 80% of conjoined twins and more than 1/5 were discordant. The surviving time of liveborn conjoined twin sets was not more than two days except in two surgically successfully separated pairs. The family study did not indicate a higher recurrence risk. The case group was compared to two control groups and it appeared that the periconceptional use of oral contraception and ovulation induction were mentioned more frequently in pregnancies resulting in conjoined twins.