The epidemiology of spina bifida in south-western Ohio--1970-1979.

Multiple epidemiological variables of 131 children with spina bifida born during 1970 and 1979 in a seven-county urban/rural region of south-western Ohio were analyzed retrospectively via personal interviews, hospital and clinic records, and birth and stillbirth certificates. The estimated incidence of spina bifida was 0.69/1000. It did not vary over the 10 years, seasonally, or in the urban vs. rural areas. The incidence for whites was three times that for non-whites. Reporting of spina bifida on the birth certificate was found for 52 per cent. Fetal loss in the children's mothers was similar to that for controls. However, there was a high number of therapeutic abortions just prior to the conception of the child with spina bifida. Oral contraceptives were used in the early months of the affected pregnancy more frequently than in controls. Recurrence risk was 3.2 per cent. Almost 12 per cent of the children with spina bifida had other major malformations. Even when the deceased probands were discounted, the malformation rate was higher than in the general population. Siblings of affected children had a less impressive but still increased rate of malformations.