Changing incidence of neural tube defects in Aegean Turkey.

The incidence of neural tube defects was monitored among all live- and still-births delivered between June 1986 and July 1988. In all there were 19,115 total births. The incidence of neural tube defects (NTD) was 1.9 per 1000 among those whose conception time was prior to May 1986. However, in conceptions occurring in May, June and July 1986, the NTD rate increased to a level of 8.9 per 1000, subsequently gradually declining to previous levels within 9 months. This dramatic change in incidence, which parallels a previous finding from Turkey, suggests that this finding may be associated with the Chernobyl disaster of May 1986.