REGARDING ENVIRONMENTAL FACTORS IN THE ETIOLOGY OF ESOPHAGEAL ATRESIA AND CONGENITAL DIAPHRAGMATIC HERNIA

We read with great interest the article by Felix et al. (2008) on the environmental factors in the etiology of esophageal atresia and congenital diaphragmatic hernia. In their case-control study they found a possible association between maternal alcohol consumption in pregnancy and the development of a congenital diaphragmatic hernia. The teratogenic effect of prenatal exposure to ethanol is well described in the literature as the cause of fetal alcohol syndrome. Many nervous system dysfunctions and patterns of craniofacial features have been described as characteristic of this syndrome, but to date there is a lack of knowledge about the spectrum of systemic effects associated with alcohol intake during pregnancy. We suppose that these data may be under-reported because of a still poor knowledge of such conditions. The mechanisms of alcohol-induced impairment of embryonic and fetal development are complex and not yet fully understood. Ethanol can induce damage directly, through its metabolites, or by inducing deficiencies or abnormalities in retinoic acid (NIAAA, 2000; Molotkov et al., 2002). In fetal alcohol syndrome, the magnitude of expression of the characteristic phenotype increases with increasing amount of maternal drinking (Astley and Clarren, 2001). Felix et al. (2008) have highlighted that alcohol could have an important role also in the development of defects of pediatric surgery pertinence. It would be interesting to know if the neonates with congenital diaphragmatic hernia of their series showed the characteristic craniofacial phenotype of the fetal alcohol syndrome. Moreover, they reported the frequency of alcohol use among mothers of newborns with congenital diaphragmatic hernia as ‘‘times per entire period or per month or per week’’. We think that it could be interesting to have a better assessment of maternal alcohol consumption, evaluating type of alcoholic beverages, trimester(s) in which alcohol was consumed, number of drinks/day, and drinks consumed per occasion. This information could help to identify if there is a positive correlation between increasing alcohol intake and additional congenital malformations, such as congenital diaphragmatic hernia, or if that association is dose-independent. Indeed, it is important to know the type of alcoholic beverages used, because red wine antioxidants could mitigate the effects of ethanol on newborns (Assunc¸a˜o et al., 2007). Further studies are needed to better assess the systemic effects of exposure to alcohol during pregnancy.