Prescription data have been analysed in order to study drug exposure of women before, during and after pregnancy as compared to non-pregnant controls. During full term pregnancy (n = 341) drug exposure increased markedly, mostly due to prescription of drugs such as iron and vitamins. Excluding these drugs, the increase was statistically significant only for one third of the women whose case records revealed some intercurrent disease during pregnancy. Women whose pregnancy ended in a spontaneous abortion (n = 29) did not differ significantly from controls in terms of drug exposure before, during or after pregnancy. In an induced abortion group (n = 60), drug exposure was more pronounced before pregnancy than in the other pregnant patients or controls. On comparing the drug history obtained from delivery records with that obtained in this study it was found that only diuretics and urinary tract chemotherapeutics had been noted fairly consistently in the former records.