Fraser F C, Frecker M, Allderdice P
Teratology. 1986 Jun;33(3):299-303. doi: 10.1002/tera.1420330307.
In Newfoundland, babies with anencephaly are conceived most often in January, and those with spina bifida in August. These and previous observations suggest that (1) seasonal fluctuations are greatest when the population frequency is neither very high nor very low, and that (2) the peak season for conception of anencephalic babies may occur in any season except August-November in various populations, whereas for spina bifida seasonal peaks are confined almost exclusively to May-August.
在纽芬兰，患无脑儿的婴儿大多在1月份受孕，而患脊柱裂的婴儿则在8月份受孕。这些以及之前的观察结果表明：（1）当人群中的发病频率既不很高也不很低时，季节性波动最为明显；（2）在不同人群中，除了8月至11月之外，无脑儿婴儿受孕的高峰季节可能出现在任何季节，而脊柱裂的季节性高峰几乎完全集中在5月至8月。
