Associations between drug consumption during pregnancy and the birth of children with oral clefts were studied in material from the Finnish Register of Congenital Malformations, consisting of 599 children with clefts and their matched controls. Information concerning maternal drug consumption was partly prospective. During the first trimester, analgesic, chemotherapeutic and antineurotic drugs had all been significantly more frequently used by the mothers of children with clefts, than by the control mothers. The consumption of drugs was in general more frequent among mothers of children with cleft lip, with or without cleft palate, than among those of children with cleft palate alone.

No abstract

The findings of a previous epidemiological study on oral clefts (599 children) were tested in an independent sample of 194 children, using the same source as for the previous study (Finnish Register of Congenital Malformations). Several of the earlier results--such as seasonal variation and associations between clefts and parental age, social factors, and emotional stress--were not reproduced. It is concluded that chance correlations introduce a marked problem to epidemiological studies. The findings of both studies show that there is an exceptionally high incidence of cleft palate in Finland. Significant geographical variations and associations between clefts and prematurity, threatened abortion during the first and second trimesters, maternal drug consumption during the first trimester, and influenza and fever during the first trimester were found. The possible role of these findings in the aetiology of oral clefts is discussed, and particular attention is paid to the possible teratogenicity of salicylates.

No abstract

The linkage between potentially teratogenic factors was studied in a material of 599 children with oral clefts and their matched controls. A method based on Yule's Q coefficient describing the degree of association between two dichotomous variables was applied. All factors studied (five groups of drugs taken by the mothers during early pregnancy, maternal influenza and fever) were significantly associated with the birth of children with clefts. The only factor whose association with clefts was explained by linkage to other factors was fever. In addition, the association between clefts and antipyretic analgesics other than salicylates could be partly explained by controlling the intake of salicylates. Although there was a strong association between influenza and consumption of salicylates, the correlation of neither of the two factors with oral clefts could be even partly explained by controlling the other. The method is considered suitable for epidemiological studies of congenital defects.