Neural tube defects in Western Australia 1966-81 and a review of Australian data 1942-81.

Abstract

Cases of neural tube defects born in Western Australia during the years 1966-1981 were identified from hospital records and death certificates. The overall rate for the 16 yr period was 1.81 cases of neural tube defects/1000 births. The rate rose and fell over the 16 yr. The initial lower rate may have been due to underascertainment, but the recent dramatic fall was statistically significant and had been observed in other Australian states and other parts of the world. This fall was not accounted for by termination of affected pregnancies before 20 wk gestation nor by demographic changes in birth order, father''s occupation or parental country of birth. The birth prevalence of neural tube defects determined in previous Australian studies was reviewed in relation to the recent decline in these disorders.