Clusters of birth defects: Emergency and management. A review of some publications

Published reports of clusters of congenital anomalies, traditionally define d as an aggregation in time and/or space of malformed cases, are interestin g to analyse in terms of emergence, management and initiator of a public he alth decision. Through some examples of clusters for which a suspected sour ce has been suggested, for those having identified important causal relatio nship or for those where the cluster appeared without any explanation, the paper shows the different steps that were taken after the initial 'alarm' a nd the time spent between the alarm and a final conclusion. If basic keys s uch as accurate field investigation, reliable estimation of the expected nu mber and etiological evaluation, are the rule, the handling should remain f lexible to take into account the particularity of each cluster. Among the c lusters of congenital anomalies published in the last 20 years, very few of them were clearly explained.