出生缺陷,也称为先天性异常,有些异常可在出生时表现,有的可在出生后一段时间才逐步呈现。这些异常既可以是由于遗传因素引起,也可以由环境因素所致,也有可能是环境因素和遗传因素共同作用的结果。出生缺陷包括先天畸形以及功能、代谢、行为的异常,目前它是全球性迫切需要解决的人口健康问题,全世界每年有至少330万5岁以下儿童死于出生 Birth defects, also known as congenital anomalies, some abnormalities can be manifested at birth, and some can be gradually emerged after some time. These anomalies can be caused either by genetic factors, by environmental factors, or by the combination of environmental and genetic factors. Birth defects, including congenital malformations, as well as abnormalities in function, metabolism and behavior, are currently a global problem of population health that is urgently needed to be addressed and at least 3.3 million children under the age of 5 die every year from birth