Population frequency of neural tube defects in the population of the city of Moscow]

A sample investigation was carried out in 14 maternity homes of Moscow during 1970--1976 in order to determine the population incidence of defects of the neural tibe. Among 282336 newborns 220 probands with these anomalies were found including 11 with syndromes of non-multifactorial etiology. The total incidence of multifactorial forms was 0.74 +/- 0.10 per 1000 newborns, the incidence of the anencephaly was 0.33 +/- 0.07% and the frequency of the spina bifida was 0.41 +/- 0.07% respectively. The sex ratio 0.61 among probands was statistically significantly different from that normal among newborns. An insignificant increase of the incidence of the defects was observed during the autumn and winter seasons. No correlation was observed between the mother's age, the birth order and the incidence of the neural tube defects.