[Prevalence of congenital malformations at birth in Chilean maternity hospitals]. / Prevalencia al nacimiento de malformaciones congénitas en las maternidades chilenas participantes en el ECLAMC en el período 2001-2010.

BACKGROUND: The Latin American Collaborative Study of Congenital Malformations (ECLAMC) is an epidemiological surveillance system operating in 11 South American countries since 1969. AIM: To analyze the Congenital Malformation prevalence rate at birth from 2001 to 2010 in Chilean Hospitals participating in ECLAMC. To compare these rates with those of the period 1982-1994. MATERIAL AND METHODS: Review of the ECLAMC database, which contains information about 282.568 newborns, 2.110 of them stillbirths (0.75%) from 13 Maternity hospitals. RESULTS: In the study period, 10.925 newborns had congenital malformations (3.9 %). Their frequency was lower in live newborns than stillbirths (3.8 and 15.3%, respectively). Compared with the 1982-1994 period, congenital malformation prevalence rates at birth were higher. They stabilized in approximately 4 %, from 1985 to 2010. The prevalence of some anomalies such as Down syndrome increased significantly. On the other hand, there was a reduction in the prevalence of spina bifida and anencephaly. CONCLUSIONS: Prevalence rates of congenital malformations at birth remained stable in the last 18 years in Chilean Hospitals participating in ECLAMC. However the prevalence of some malformations such as Down syndrome, Polydactyly, anotia-microtia, syndactyly and cleft palate have increased. The prevalence rates of spina bifida and anencephaly have decreased.

[Experience of a research Ethics Committee and the challenges of the new Chilean legislation on research in human beings]. / Experiencia del Comité de Ética de Investigación en Seres Humanos de la Facultad de Medicina de la Universidad de Chile y los desafíos que impone la nueva legislación chilena en la investigación médica.

The welfare of research participants must be guaranteed by international ethical standards. This article communicates the procedures of the Research Ethics Committee of the School of Medicine, University of Chile (CEISH). The new Chilean legislation on research in human beings is also discussed. Law 20.120: "On scientific research in human beings, its genome and forbidding human cloning" establishes the ethical principles that must be accomplished in every research involving human beings. Article 28 of the Law 20.584 "Regulation of the rights and duties of health care users", forbids the participation of handicapped people who cannot express their will in scientific research. Article 13 states that people not related directly with patient care cannot have access to his clinical records (with the exception of people with notarial authorization by the patient). CEISH proposes that, in case of people with intellectual deficiency, the decision to approve a scientific research should be analyzed on an individual basis. If the person is capable of expressing his or her will or has stated his or her consent beforehand, the research can be authorized. If the person cannot express his or her will, the scientific research cannot take place. In prospective studies, a consent from the patient and an authorization of the health authority should be required to access clinical records. In retrospective studies, consent should be obtained from the patient when personal information is going to be used. If the information is nameless, the consent can be disregarded.

[Effects of wheat flour fortification with folic acid on the prevalence of neural tube defects in Chile]. / Resultados del Programa de Prevención de Defectos de Tubo Neural en Chile mediante la fortificación de la harina con ácido fólico: Período 2001-2010.

BACKGROUND: Congenital malformations (CMF) have an important role in infant mortality. Neural tube defects (NTD) have great relevance from both social and public health points of view. The ECLAMC (Collaborative Latin American Study of Congenital Malformations) maintains in Chile an epidemiological surveillance of CMF prevalence rate at birth since 1969. AIM: To assess the effect of wheat flour folic acid fortification on the prevalence of NTD. PATIENTS AND METHODS: Only Anencephaly, Spina bifida and Cephalocele were considered as NTD. All children born in the maternities incorporated to ECLAMC between 1969 and 1999 were considered as belonging to the pre folic acid fortification period and those who were born from 2001 to 2010 were considered as belonging to the post fortification period. RESULTS: The NTD prevalence rate at birth in the pre fortification period was 17.03/10,000. In the second period, there were 291,996 births and among them, 280 newborns were affected by a form of NTD (9.59 in 10,000 births). This represents a 44% decrease (p < 0.01). Anencephaly rate fell from 7.16/10,000 to 3.67/10,000, representing a 49% lower rate (p < 0.01). Spina bifida rate decreased from 8.61/10,000 to 4.49/10,000, representing a 48% lower rate (p < 0.01). Cephalocele had a 20% non-significant reduction. CONCLUSIONS: Wheat flour fortification with folic acid reduced by 44% the prevalence rate of NTD at birth. This means that NTDs were prevented in 185 Chilean newborns each year.

[Congenital malformations among newborns of teenage mothers]. / Prevalencia al nacimiento de malformaciones congénitas en hijos de madres adolescentes. Hospital Clínico Universidad de Chile. Período 2002-2011.

BACKGROUND: The Chilean Ministry of Health has reported a meaningful increase of births from teenager mothers (aged less than 20 years) in the period 1990-2008. On the contrary, there was a decrease of births from teenage mothers at The University of Chile Clinical Hospital (HCUCH). AIM: To compare the prevalence rates at birth of congenital malformations (CMF) in newborns from mothers younger than 20 with those of mothers between 20 and 34 years old. PATIENTS AND METHODS: The Latin American Collaborative Study of Congenital Malformations (ECLAMC) data base of the HCUCH, since 1969 was analyzed. The last ten years (2002-2011) were studied. RESULTS: There were 15,636 births in the period studied, 153 of them were stillbirths (0.97%). There were 1174 newborns from teenage mothers, 82 of them had one or more congenital malformations (7%). We found an association between smoking and drug consumption in mothers and CMF in their newborns. CONCLUSIONS: The rate of congenital malformations among offspring of teenage mothers is lower than the rate for mothers between 20 and 34 years old.

[Congenital malformations in Latin America in the period 1995-2008]. / Malformaciones congénitas en Chile y Latino América: una visión epidemiológica del ECLAMC del período 1995-2008.

BACKGROUND: The Latin American Study of Congenital Malformations (ECLAMC) has performed an epidemiological surveillance of congenital malformations since 1967. This allows to detect any unexpected change in the incidence of malformations, possibly caused by a new environmental teratogenic agent. AIM: To report a summary of the results thus far obtained in this study. MATERIAL AND METHODS: The ECLAMC database was analyzed and all live births and stillbirths of more than 500 grams in the period 1995-2008, were analyzed. RESULTS: There were 2,409,407 births in the nine participant countries. Of these 31,516 (1.3%) were stillbirths. The global rate of congenital malformations in this sample was 2.7%. In the studied period, there was a significant reduction in the rates of anencephaly and spina bifida in Chile and Argentina. In the rest of the countries, the global rates of malformations increased. Venezuela had the higher rate of teenage pregnancies (25%), followed by Colombia (23%). Chile had the higher percentage of women aged 35 years or more giving birth (14%), followed by Uruguay (13%). However, Chile had the higher rate of Down syndrome and Uruguay, the lowest (24.7 and 13.6 per 10000). CONCLUSIONS: There is a tendency towards an increase in the rates of congenital malformations in this sample, with significant differences among countries.

Aspectos éticos y recomendaciones para investigación en seres humanos en la era genómica / Ethical aspects and recommendations for human research in the genomic age

Este artículo revisa los principales desafíos éticos que plantea la investigación vinculada al genoma humano a la luz de la bibliografía internacional y entrega recomendaciones sobre su abordaje basada en nuestra experiencia en el Comité de Ética para la Investigación en Seres Humanos de la Facultad de Medicina, Universidad de Chile, incluyendo las regulaciones legales nacionales. Los estándares éticos de la investigación en seres humanos deben extremarse para proteger adecuadamente a los participantes en estudios involucrados con la genómica. Especialmente relevantes en este contexto son: la protección de la confidencialidad y anonimato; la política de entrega de resultados y la posibilidad de retirarse del estudio. Compartir datos resultantes de investigaciones genéticas permite optimizar recursos, otorga mayor transparencia y replicabilidad de los análisis y permite descubrir alteraciones genéticas responsables de enfermedades raras y genes involucrados en enfermedades hereditarias multifactoriales, además de contribuir al diseño de medicina de precisión y de nuevas estrategias terapéuticas. Sin embargo, plantea grandes desafíos: proteger la privacidad y evitar la re-identificación de los voluntarios, la entrega de resultados con asesoría pre y post estudio. Estos aspectos requieren la elaboración de un cuidadoso proceso de consentimiento informado para investigaciones genómicas cuyos componentes principales se analizan en este artículo.

This article reviews the main ethical challenges posed by human genome research in the light of the international literature and provides recommendations on how to approach them based on our experience in the Ethics Committee for Research on Human Subjects of the Faculty of Medicine, University of Chile, including national legal regulations. Ethical standards in human research must be extreme, in order to adequately protect participants in studies involving genomics. Particularly relevant in this context are the protection of confidentiality and anonymity; the policy of delivery of results and the possibility of withdrawing from the study. Sharing data resulting from genetic research optimizes resources, provides greater transparency, and replicability of the analyses and makes it possible to discover genetic alterations responsible for rare diseases and genes involved in multi-factorial hereditary diseases, as well as contributing to the design of precision medicine and new therapeutic strategies. However, it poses great challenges: protecting privacy and avoiding re-identification of volunteers, delivery of results with pre- and post-study counseling. These aspects require the elaboration of a careful informed consent process for genomic research, the main components of which are discussed in this article.

Polimorfismos genéticos asociados a la inmunidad innata y la susceptibilidad genética a la tuberculosis / Genetic polymorphisms associated with innate immunity and to genetic susceptibility to tuberculosis

Resumen La tuberculosis es un problema de salud mundial exacerbado por la ausencia de una vacuna eficaz y la emergencia de cepas multidrogo resistentes. La inmunidad innata, clave en la susceptibilidad a tuberculosis, está asociada a polimorfismos genéticos en TLRs (Toll Like Receptors), VDR (Vitamin D Receptor), INF-γ, TNF-α, entre otros. Recientemente, también a nueve genes causantes de susceptibilidad mendeliana a enfermedades micobacterianas (MSMD), incluyendo genes autosómicos y ligados al cromosoma X. Después de décadas de exitoso manejo, Chile reportó mantención de la mortalidad, aumento en la incidencia de tuberculosis en todas sus formas y casos multidrogo resistentes. La incidencia es mayor en Norte y Centro, donde la Región Metropolitana mostró incremento de población migrante latinoamericana. Consecuentemente, la alta persistencia de la incidencia en tales zonas geográficas, podría asociarse a poblaciones portadoras de polimorfismos de un solo nucleótido (SNP)s y/o MSMD, confiriendo susceptibilidad genética a tuberculosis y/o a BCG diseminada y otros patógenos intramacrofágicos, similar a lo descrito en poblaciones de Europa, Asia, África y América. En conclusión, proponemos considerar la predisposición genética de la población actual, al momento de diseñar políticas nacionales de salud pública para erradicar la tuberculosis.

Tuberculosis is a global health problem exacerbated by the absence of an effective vaccine and emergence of extensive antibiotic-resistant strains. Innate immunity is key to tuberculosis susceptibility, since it is associated with genetic polymorphisms in TLRs (Toll Like Receptors), VDR (Vitamin D Receptor), INF-γ, TNF-α, among others. Recently, also to nine Mendelian Susceptibility Mycobacterial Diseases (MSMD) -causing genes, including autosomal and X-linked genes. After decades of successful management, Chile reported maintenance of mortality and increase in tuberculosis under 15 years and multidrug resistant cases incidence. Moreover, incidence is higher in the North and the Center, where Metropolitan Region showed a sustained increment of the Latin American migrant population. Consequently, the high incidence persistence in such geographic areas could be associated with populations carrying SNPs genetic polymorphisms types and/or MSMD that confer genetic susceptibility to tuberculosis and/or BCG dissemination and other intramacrophagic pathogens, similar to that described in certain populations in Europe, Asia, Africa and America. Corollary, we propose to consider genetic predisposition of the current population, at the time of designing national public health policies to eradicate tuberculosis.

Prevalencia al nacimiento de malformaciones congénitas en las maternidades chilenas participantes en el ECLAMC en el período 2001-2010 / Prevalence of congenital malformations at birth in chilean maternity hospitals

Background: The Latin American Collaborative Study of Congenital Malformations (ECLAMC) is an epidemiological surveillance system operating in 11 South American countries since 1969. Aim: To analyze the Congenital Malformation prevalence rate at birth from 2001 to 2010 in Chilean Hospitals participating in ECLAMC. To compare these rates with those of the period 1982-1994. Material and Methods: Review of the ECLAMC database, which contains information about 282.568 newborns, 2.110 of them stillbirths (0.75%) from 13 Maternity hospitals. Results: In the study period, 10.925 newborns had congenital malformations (3.9 %). Their frequency was lower in live newborns than stillbirths (3.8 and 15.3%, respectively). Compared with the 1982-1994 period, congenital malformation prevalence rates at birth were higher. They stabilized in approximately 4 %, from 1985 to 2010. The prevalence of some anomalies such as Down syndrome increased significantly. On the other hand, there was a reduction in the prevalence of spina bifida and anencephaly. Conclusions: Prevalence rates of congenital malformations at birth remained stable in the last 18 years in Chilean Hospitals participating in ECLAMC. However the prevalence of some malformations such as Down syndrome, Polydactyly, anotia-microtia, syndactyly and cleft palate have increased. The prevalence rates of spina bifida and anencephaly have decreased.

Prevalencia al nacimiento de malformaciones congénitas en hijos de madres adolescentes. Hospital Clínico Universidad de Chile: Período 2002-2011 / Congenital malformations among newborns of teenage mothers

Background: The Chilean Ministry of Health has reported a meaningful increase of births from teenager mothers (aged less than 20 years) in the period 1990-2008. On the contrary, there was a decrease of births from teenage mothers at The University of Chile Clinical Hospital (HCUCH). Aim: To compare the prevalence rates at birth of congenital malformations (CMF) in newborns from mothers younger than 20 with those of mothers between 20 and 34 years old. Patients and Methods: The Latin American Collaborative Study of Congenital Malformations (ECLAMC) data base of the HCUCH, since 1969 was analyzed. The last ten years (2002-2011) were studied. Results: There were 15,636 births in the period studied, 153 of them were stillbirths (0.97%). There were 1174 newborns from teenage mothers, 82 of them had one or more congenital malformations (7%). We found an association between smoking and drug consumption in mothers and CMF in their newborns. Conclusions: The rate of congenital malformations among offspring of teenage mothers is lower than the rate for mothers between 20 and 34 years old.

Resultados del Programa de Prevención de Defectos de Tubo Neural en Chile mediante la fortificación de la harina con ácido fólico: Período 2001-2010 / Effects of wheat flour fortification with folic acid on the prevalence of neural tube defects in Chile

Background: Congenital malformations (CMF) have an important role in infant mortality. Neural tube defects (NTD) have great relevance from both social and public health points of view. The ECLAMC (Collaborative Latin American Study of Congenital Malformations) maintains in Chile an epidemiological surveillance of CMF prevalence rate at birth since 1969. Aim: To assess the effect of wheat flour folic acid fortification on the prevalence of NTD. Patients and Methods: Only An encephaly, Spina bifida and Cephalocele were considered as NTD. All children born in the maternities incorporated to ECLAMC between 1969 and 1999 were considered as belonging to the pre folic acid fortification period and those who were born from 2001 to 2010 were considered as belonging to the post fortification period. Results: The NTD prevalence rate at birth in the pre fortification period was 17.03/10,000. In the second period, there were 291,996 births and among them, 280 newborns were affected by a form of NTD (9.59 in 10,000 births). This represents a 44% decrease (p < 0.01). Anencephaly rate fell from 7.16/10,000 to 3.67/10,000, representing a 49% lower rate (p < 0.01). Spina bifida rate decreased from 8.61/10,000 to 4.49/10,000, representing a 48% lower rate (p < 0.01). Cephalocele had a 20% non-significant reduction. Conclusions: Wheat flour fortification with folic acid reduced by 44% the prevalence rate of NTD at birth. This means that NTDs were prevented in 185 Chilean newborns each year.

Defectos de la pared abdominal. Estudio comparativo entre onfalocele y gastrosquisis / Abdominal wall defects. A Comparative investigation between omphalocele and gastroschisis

Introducción: Onfalocele y gastrosquisis son los defectos de la pared abdominal (DPA) más frecuentes, que por su importancia y las diferencias entre ellos merecen ser estudiados en forma especial. Objetivos: Establecer las tasas de prevalencia de onfalocele y gastroaquisis al nacimiento. Verificar variaciones de ellas en distintos períodos. Estudiar la morbimortalidad asociada y su sobrevida. Pacientes y Método: Se revisó la base de datos ECLAMC (Estudio Colaborativo Latino Americano de Malformaciones Congênitas) para el período 1996-2010. Resultados: Se pesquizarón 33 recién nacidos (RN) con DPA. (11,6 por 10.000 nacimientos). De ellos 19 fueron onfalocele (6,7 por 10.000) y 14 (4,9 por 10.000) gastrosquisis. Los niños con onfalocele tenían significativamente mayor asociación con otras malformaciones, su frecuencia en el sexo masculino fue mayor y mostró mayor letalidad que la gastrosquisis. Todos los niños con gastrosquisis nacieron vivos, con predominio del sexo femenino, sus madres eran significativamente más jóvenes. Conclusión: Onfalocele y gastros-quisis presentaron una prevalencia al nacimiento mayor que lo publicado, probablemente por ser el HCUCH un Centro de Referencia. Ambas anomalías mostraron un aumento significativo en sus tasas de prevalencia al nacimiento al compararlas con las obtenidas anteriormente por nosotros en el mismo hospital. Se demostró diferencias significativas entre estas dos entidades: Onfalocele tiene mayor mortinatalidad, mortalidad y letalidad, mayor frecuencia de malformaciones asociadas y mayor promedio de edad materna.

Introduction: Omphalocele and Gastroschisis are the two most common congenital abdominal wall (AWD) defects. Objectives: To determine birth prevalence of Omphalocele and Gastroaquisis; to verify variations in different periods and to study the associated morbidity, mortality and survival. Patients and Method: The database of the Latin American Collaborative Study of Congenital Malformations (ECLAMC) was searched between the years 1996 and 2010. Results: 33 newborns (NB) with AWD were investigated (11.6 per 10,000 births). 19 of the cases corresponded to omphalocele (6.7 per 10,000 births) and 14 to gastroschisis (4.9 per 10,000 births). Children with omphalocele had significantly greater association with other malformations and the frequency in males was higher and showed higher mortality rates than gastroschisis. All children with gas-troschisis were born alive; they were predominantly female infants whose mothers were significantly younger. Conclusion: Birth omphalocele and gastroschisis prevalence were higher than published information, perhaps due to the fact that the HCUCH (Clinical Hospital of Universidad de Chile) is a reference center. Both anomalies showed a significant increase in their birth prevalence rates when compared with those previously obtained by us in the same hospital. Significant differences between these two entities were described. Omphalocele presented higher stillbirth, mortality and fatality rates; higher frequency of associated malformations and higher average maternal age.

[Paternal age as a risk factor for congenital malformations]. / La edad paterna como factor de riesgo para malformaciones congénitas.

BACKGROUND: The role of advanced maternal age as a risk factor for congenital malformations in offspring is known. However, the influence of paternal age is not clear. AIM: To evaluate the association between advanced paternal age and the risk for congenital malformations. PATIENTS AND METHODS: Analysis of maternal and paternal age of cases (malformed newborns) and controls from ECLAMC Database (Latin American Collaborative Study of Congenital Malformations) registered at the University of Chile Clinical Hospital during the decade from Jan 1 1997 to Dec 31 2006. Newborns and stillborns were grouped according to maternal age into 6 intervals. In each interval, paternal ages of cases and controls were compared. The inverse procedure was performed to assess maternal age effect. Other variables as gestational age and birth weight were analyzed for the intervals of maternal and paternal ages. RESULTS: No significant differences were observed in paternal age between cases and controls in any of the intervals of maternal age. However, mean maternal age was higher for cases than for controls (p =0,0149). Gestational age and birth weight depend more on being case or control than on the age of parents. CONCLUSIONS: No differences in paternal age were observed between cases and controls in this series of newborns.

Frecuencia de la mutación 35delG del gen GJB2 (conexina 26) en una muestra de escolares sordos de Santiago / Frequency of the 35delG mutation of GJB2 (connexin 26) in a sample of deafschool children in Santiago

Introducción: Se estima que 1 de cada 1.000 niños presenta hipoacusia severa al nacimiento o en los primeros meses de vida y el 50 por ciento de las hipoacusias congénitas se relacionan con el gen de la conexina 26 (GJB2). En poblaciones caucásicas la variante patogénica 35delG del gen GJB2, que es la más frecuente, se encuentra en 30 por ciento de los pacientes con hipoacusia congénita no sindrómica. En Chile, la frecuencia de esta variante en escolares sordos no está descrita. Objetivos: Estimar la frecuencia de la mutación 35delG del gen GJB2 en niños con sordera congénita no sindrómica y no atribuible a causas ambientales conocidas, de colegios especiales de Santiago. Correlacionar la presencia de 35delG con los antecedentes clínicos de estos niños. Material y método: Se determinó la presencia de la mutación 35delG mediante PCR alelo específico y secuenciación automatizada en 81 escolares. Se buscó asociar la presencia de 35delG y los antecedentes clínicos de los niños mediante la prueba exacta de Fisher. Resultados: En el grupo estudiado, el 11,25 por ciento de los casos presentaron la variante 35delG, siendo ésta más frecuente en los casos en que había antecedentes familiares de sordera. En 8 casos se encontró una variante considerada no patogénica V27I. Conclusión: La frecuencia de la mutación 35delG fue inferior a lo esperado, probablemente debido al método de selección de los niños a estudiar (aquellos cuyos padres no referían causa conocida de sordera, lo cual no fue refrendado por exámenes de laboratorio que permitieran descartar enfermedades infecciosas u otras condiciones causantes de sordera).

Introduction: Congenital hearing loss occurs in 1 in 1000 live births and 50 percent of these cases are related with mutations in the connexin26 gene (GJB2). The 35delG variant is the most common of the known pathogenic alleles in Caucasian populations, reaching a frequency of 30 percent among the non syndromic congenital deaf people. The frequency of this variant has not been described in Chilean deaf children. Aim: To estimate the frequency of the 35delG GJB2 gene mutation in children with non syndromic congenital hearing loss of unknown etiology from deaf schools in Santiago, and to evaluate the association between clinical features of these children and the presence of the 35delG allele. Material and method: The presence of the 35delG mutation was studied by allele specific PCR and automatical sequencing in 81 children. The association between clinical issues and genotypes was explored by Fisher exact test. Results: We found the 35delG variant in 11,25 percent of the children, this mutation was more frequent in familial cases than sporadic cases of deafness. We also found the V27I non pathogenic variant in 8 cases. Conclusion: The frequency of the 35delG mutation was lower than the expected, probably due to the criterion used to select the school children to be studied.

Cambios en la distribución etaria de las madres en Chile y en el Hospital Clínico de la Universidad de Chile y su influencia en la morbimortalidad neonatal / Change in the age distribution of mothers in Chile and its influence on neonatal morbidity

Antecedentes: En las últimas décadas en Chile y otros países Sudamericanos se ha producido un cambio en la distribución etaria de las madres. Objetivos: Obtener la distribución de los nacimientos por grupos de edades maternas en el Hospital Clínico de la Universidad de Chile (HCUCH) y compararlos con iguales grupos en todo Chile. Comprobar que los grupos de edades extremas están aumentando. Estudiar la relación entre estos cambios con algunas patologías del recién nacido, como prematuridad, recién nacidos pequeños para su edad gestacional (PEG) y malformaciones congénitas. Método: Datos de la maternidad del HCUCH (1982-2010) y del Ministerio de Salud (1990-2008). Se distribuye a las madres en 3 grupos: <20, >35 y 20-34 años. Las comparaciones se hicieron con prueba de Chi Cuadrado. Resultados: En Chile el grupo de madres >35 años aumentó en más del 50 por ciento al comparar los años 1990 (10,2 por ciento del total) y 2008 por ciento(15,8 por ciento) (p<10-8). Las madres adolescentes en Chile aumentaron de 13,8 por ciento en 1990 a 16,6 por ciento en 1998 (p<10-8). En el HCUCH las adolescentes disminuyeron de 16,08 por ciento en 1982 a 9,09 por ciento en 2010 (p<10-8). Las >35 años aumentaron significativamente, al igual que en Chile, de 9,8 por ciento en 1982 a 22,17 por ciento en el año 2010 (p<10-8). Esta distribución etaria en el HCUCH (1996-2010) se asoció con otros cambios significativos: disminuyeron los RN PEG (p=0,02) y los prematuros (<37 semanas) aumentaron significativamente (p<0,00001). El grupo de mujeres >35 años se asocia con mayor cantidad de RN femeninos, malformaciones congénitas, síndrome de Down y partos por cesárea.

Introduction: In recent decades, both in Chile and other South American countries there has been a change in the age distribution of mothers. Objectives: To obtain the distribution of births by maternal age groups in the Hospital Clinic of the University of Chile (HCUCH) and compare them with similar groups throughout Chile. Check that the extreme age groups are increasing. To study the relationship between these changes and some diseases of the newborn, such as prematurity, infants small for gestational age (SGA) and birth defects. Methods: We reviewed the database of the Maternity HCUCH (1982-2010) and of the Ministry of Health (19902008). The mothers are distributed in 3 groups: <20, >35 and between 20-34 years. Comparisons were made with chi square test. Results: In Chile, the group of mothers >35 years old has increased by over 50 percent when comparing the 1990 (10.2 percent of total) and 2008 15.8 percent (p<10-8). Teenager mothers in Chile increased from 13.8 percent in 1990 to 16.6 percent in 1998 (p<10-8). In the HCUCH variations were different, adolescents decreased 16.08 percent in 1982 to 9.09 percent in 2010 (p<10-8). The >35 years increased significantly, as in all of Chile, 9.8 percent in 1982 to 22.17 percent in 2010 (p<10-8). The live birth age distribution in the HCUCH (1996-2010) led to significant changes: reducing SGA (p=0.02), the premature (<37 weeks) increased significantly (p<0.00001). The group of women >35 years is associated with increased number of children women, congenital malformations, Down syndrome and cesarean deliveries.

[The association between maternal age and congenital malformations]. / Edad materna y malformaciones congénitas: un registro de 35 años. 1970-2005.

BACKGROUND: There is an association between extreme maternal ages and the risk of congenital malformations. This is specially true for chromosomal abnormalities among women of advanced ages and disruptive malformation among teenage mothers. AIM: To determine the association between maternal ages and incidence of congenital malformations at the obstetric ward of a clinical hospital. To compare these figures with those of Chile. MATERIAL AND METHODS: The hospital registries of the Latin American Collaborative Study of Congenital Malformations (ECLAMC) between 1996 and 2005, were consulted. This is a database of all malformations detected in newborns at the hospital. RESULTS: An overall prevalence of malformations of 8,4% was detected at the hospital. There is a significantly lower frequency of mothers aged less than 20 years than in the rest of Chile. Mothers aged between 20 and 29 years have the lower frequency of malformed children. Women aged less than 20 years and over 39 years of age account for 56% of malformed children. Maternal ages and the rates of malformations, increased in a parallel fashion at a rate of 0.2 years and 2.2 malformed children per 1,000 born alive, per calendar year, respectively. CONCLUSIONS: The association between prevalence rates of congenital malformations and maternal age is U shaped with a higher proportion of malformed children among women aged less than 20 years or more than 39 years.

[Effects of folic acid fortification in the rates of malformations at birth in Chile]. / Efecto de la fortificación de la harina con ácido fólico sobre la evolución de las tasas de prevalencia al nacimiento de malformaciones congénitas en los hospitales chilenos del ECLAMC.

BACKGROUND: The effects of folic acid fortification on neural tube defects is well known. Other reports show a beneficial effect of the fortification on orofacial clefts, urinary malformations and defects caused by limb reduction. AIM: To determine the changes in prevalence of congenital malformations after the start of flour folic acid fortification in Chile. MATERIAL AND METHODS: The rates of 22 malformations occurring in the maternity of the University of Chile Clinical Hospital and other Chilean hospitals participating in the Latin American Collaborative Study of Congenital Malformations (ECLAMC) were compared before and after the start of flour folic acid fortification. RESULTS: After the start of folic acid fortification a significant reduction in the rates of anencephalia, spina bifida and diaphragmatic hernia, was observed. The rates of all other malformations remained stable or increased. The rates of all malformations at the University of Chile Clinical Hospital had a steady increase until 2005 and were significantly higher than in the rest of hospitals participating in ECLAMC. CONCLUSIONS: Folic acid fortification was associated with an expected reduction in rates of spina bifida and anencephalia and an unexpected reduction in the rates of diaphragmatic hernia.

Estudio epidemiológico global del síndrome de Down / Global epidemiological study of Down's syndrome

Introduction: In 1967, the Latin American Collaborative Study of Congenital Malformations (LASCM) was created. Currently, 180 hospitals in 76 cities of 9 Latin American countries participate, accumulating data from over 4.5 M births. The Clinical Hospital of the University of Chile (HCUCH) entered the study in 1967, as did 12 other institutions later on. Objectives: Verify changes (increase) in frequency of Down's Syndrome (DS) in Chile and Latin America, and modification of frequency in those countries where elective abortion is permitted. Patients y Method: Three samples were evaluated: Births at HCUCH, active chilean hospitals and the 180 hospitals in 9 LA countries between 1972 and 2009. DS frequencies in Chile and other countries were compared through the International Clearinghouse for Birth Defects Monitoring System. Results: DS frequency at HCUCH increased significantly from 1.03 per thousand births in 1972 to 2.93 /oo births 2009. Frequencies in all chilean hospitals are fairly homogeneous, all higher than average for LASCM, which is 1.88 per thousand. The chilean average is 2.47/ºº por the period between 1998-2005, with a range of 1.88 at HCUCH to 2.86 at the Hospital of Curicó. In the rest of the world, the rate of DS per birth has diminished significantly, being the lowest in Iran (0.32/o<>) and Spain (0.6/oo live births). Conclusion: Rate of DS births are higher in Chile than LASCM average (2.47/o<>), with a trend to increase. This is true in Latin America, where the average for the period between 2001-2005 was 2.89 per thousand live births. In Europe and Asia, these rates have decreased to very low numbers, such as 0.32/o<> in Iran and 0.6/o<> in Spain.

Introducción: El ECLAMC (Estudio Colaborativo Latino Americano de Malformaciones Congenitas) fue creado en 1967. Actualmente, lo integran 180 hospitales de 76 ciudades de 9 países Latino Americanos y ha acumulado más de 4,5 millones de nacimientos. El Hospital Clínico de la Universidad de Chile (HCUCH) ingresó en 1967 y después otros 12 establecimientos chilenos. Objetivos: Verificar si la frecuencia de síndrome de Down (SD) está aumentando en Chile y Latino América y como se ha visto modificada en los países en que está permitido el aborto electivo. Pacientes y Método: Se estudió 3 muestras: Todos los nacimientos del HCUCH desde 1972 a 2009; de los hospitales chilenos activos y de los 180 hospitales de 9 países Latinoamericanos. Se comparó las frecuencias de SD de Chile y del ECLAMC con otros países que participan en el Internacional Clearinghouse for Birth Defects Monitoring System. Resultados: La frecuencia del SD en el HCUCH aumentó significativamente de 1,03 por mil nacimientos en 1972 a 2,93 por mil en 2009. Las frecuencias en los hospitales chilenos son muy homogéneas, todas más altas que el promedio del ECLAMC: 1,88 por mil. El promedio chileno para el período 1998-2005 fue de 2,47 por mil. Con un rango de 1,88 por mil del HCUCH y 2,86 por mil del Hospital de Curicó. En el resto del mundo se ha asistido a una disminución significativa de las tasas de SD, siendo las más bajas la de Irán: 0,32 por mil y España 0,60 por mil nacimientos vivos. Conclusión: En Chile, las tasas de SD son mayores al promedio del ECLAMC 2,47 por mil existiendo una tendencia al aumento de ellas lo mismo que en Latino América, donde el promedio para el período 20012005 fue de 2,89 por mil. En Europa y Asia las tasas han disminuido a cifras extremas, Irán 0,32 por mil y España 0,60 por mil.

Malformaciones congénitas en Chile y Latino América: Una visión epidemiológica del ECLAMC del período 1995-2008 / Congenital malformations in Latin America in the period 1995-2008

Background: The Latin American Study of Congenital Malformations (ECLAMC) hasperformed an epidemiológica! surveillance of congenital malformations since 1967. This allows to detectany unexpected change in the incidence of malformations, possibly caused by a new environmental teratogenic agent. Aim: To report a summary ofthe results thusfar obtained in this study. Material ana Methods: The ECLAMC datábase was analyzed and all Uve births and stillbirths ofmore than 500 grams in the period 1995-2008, were analyzed. Results: There were 2,409,407 births in the nine participant countries. Ofthese 31,516 (1.3 percent) were stillbirths. The global rate of congenital malformations in this sample was 2.7 percent. In the studied period, there was a significant reduction in the rates of anencephaly and spina bifida in Chile and Argentina. In the rest ofthe countries, the global rates of malformations increased. Venezuela had the higher rate of teenage pregnancies (25 percent), followed by Colombia (23 percent). Chile had the higherpercentage ofwomen aged 35years or moregiving birth (14 percent), followed by Uruguay (13 percent). However, Chile had the higher rate of Down syndrome and Uruguay, the lowest (24.7 and 13.6per 10000). Conclusions: There is a tendency towards an increase in the rates of congenital malformations in this sample, with significant differences among countries.

[Increasing rates of Down syndrome among newborns in Chile from 1972 to 2005]. / Vigilancia epidemiológica del síndrome de Down en Chile, 1972 a 2005.

BACKGROUND: There are some records shrowing that the frequency of Down syndrome is experiencing an increase over time. AIM: To verify whether the frequency of Down syndrome is increasing in the maternity of the University of Chile Clinical Hospital, or in other Chilean hospitals participating in the Latin American Collaborative Study of Congenital Malformations (ECLAMC) and compare the rates with other world registries of congenital malformations. MATERIAL AND METHODS: The information was obtained from the ECLAMC databases of the maternity. The Down syndrome incidence rates were calculated from 1997 to 2005 and rate curves were constructed. RESULTS: The overall rate of Down syndrome was 3.36 per 10,000 born alive. This rate experienced a significant increase in the study period. These rates differ in the different Chilean regions, being higher in Santiago and lower in the Southern regions of the country. The mean age of mothers of newborns with or without Down syndrome was 36+/-6 and 29+/-6 years, respectively, p >0.001. CONCLUSIONS: The rates of newborns with Down syndrome increased in the period 1972-2005, bearing a close relationship with the increase in maternal ages.

[The frequency of twin pregnancies increased in a Chilean hospital associated with periconceptional flour folic acid supplementation]. / La frecuencia de nacimientos de gemelos aumentó en un hospital chileno coincidiendo con el consumo periconcepcional de harina fortificada con ácido fólico.

BACKGROUND: A significant increase in the frequency of twins has been described in the literature as a secondary effect of perinatal supplementation with folic acid. AIM: To verify if the frequency of twins increased in a Chilean hospital, after the start of flour folic acid supplementation. MATERIAL AND METHODS: The frequency of twins was compared in the University of Chile Clinical Hospital, before and after the start of flour fortification with folic acid. RESULTS: There was a 34% increase in the frequency of twins during the post fortification period (2001-2004) as compared with the previous period (1998-2000). A decrease in the frequency of male twins, when compared with single newborns, was also observed in the post fortification period. There was a higher frequency of stillborns among twins, when compared with single newborns. CONCLUSIONS: The frequency of twin pregnancies increased after flour folic acid supplementation in sample of Chilean population.