§ Mr. Luceasked the Secretary of State for Social Services how many cases of thrombosis per annum since 1965 have been caused by birth control pills.
§ Dr. OwenThrombosis can occur spontaneously in any woman. The risk is enhanced by cigarette smoking, diabetes212W or high blood pressure. It is also increased by the use of oral contraceptives. Figures are not available on an annual basis, but the results of a large study by the Royal College of General Practitioners suggest that the additional risk attributable to the use of oral contraceptives would amount to about 0.24 per cent. of cases of thrombosis per year. On the estimate that 2½ million women in the United Kingdom are using oral contraceptives, some 6,000 women would be expected each year to develop thrombosis as a result of this use. Approximately 40 per cent. of these women would develop thrombosis affecting only superficial veins in the leg. Only a small proportion of women with thrombosis require hospital admission.