国外一项大规模调查显示:近30年来,婴儿死亡中营养性、感染性死亡已逐渐减少,但出生缺陷所占的比例却相对增多,甚至在一些发达国家中,出生缺陷在婴儿死亡中已居首位。据统计,我国每年至少有30万缺陷儿出生。 导致出生缺陷主要有两大原因:一是遗传因素,占25％;二是环境因素,这方面统计尚无准确数字。有专家认为,大多数出生缺陷是遗传因素和环境因素相互 A large-scale survey abroad shows that in the past 30 years, the number of infant deaths has decreased gradually from nutritional and infectious deaths, but the proportion of birth defects has increased. Even in some developed countries, birth defects have been reported in infant deaths Habitat first place. According to statistics, at least 300,000 defective children are born in China each year. Birth defects lead to two main reasons: First, genetic factors, accounting for 25%; Second, environmental factors, there is no accurate statistics in this regard. Some experts believe that most birth defects are genetic and environmental factors