Seasonal Variations in the Incidence of some Congenital Anomalies in

Background: Birth defects represent one of the main causes of infant mortality and morbidity around the world. Objective: The purpose of this study is to identify seasonal changes in the incidence of various congenital anomalies in our population. Methods: We identified all cases of open neural tube defects, cardiac anomalies, cleft lip and palate and gastroschisis of children born in Puerto Rico and reported to the Health’s Department Birth Registry Program between January 1995 and December 2005. The conception dates were determined by estimation based on the reported last menstrual period. All deliveries during this same period were recorded and their conception dates estimated in the same manner