一般认为,神经管缺陷(NTD)患儿的出生有季节变化。作者着重研究了受累胎儿和新生儿的妊娠日期,以期证实NTD发病率的可变性是预防研究的一个重要因素的假设。在1976年至1981年6年期间,对临床中 It is generally believed that there is a seasonal variation in the birth of children with neural tube defects (NTD). The authors focused on the date of pregnancy of affected fetuses and newborns to establish the hypothesis that variability in the incidence of NTD is an important factor in prevention research. During the six years from 1976 to 1981, it was in clinical practice