Defects of the central nervous system in Finland: III. Disease and drugs in pregnancy.

The matched pair system of the Finnish Register of Congenital Malformations was used to search for association between defects of the central nervous system (CNS), and maternal diseases and/or drug consumption during pregnancy. The study material consisted of 710 cases with CNS defects and their controls. Significant associations were found for the following conditions: influenza, threatened abortion, depressive state, toxemia of pregnancy, diabetic mothers, and for the consumption of the following drugs: salicylates, pyrazolones/anilines, euphoristic analgesics, sympathomimetics, barbiturates, and cough medicines. 259 cases with polydactyly and their controls were also compared, with a view to demonstrating what biases might be introduced by the case-control method. After utilizing the possibilities of this design for examining the above mentioned significant associations, the factors to be seriously considered were reduced to the following ones: influenza, depressive state, toxemia of pregnancy, diabetic mothers and cough medicines.