In a non-randomised controlled study of 37,048 women undergoing hysterectomy, 0 out of 1,154 of those treated with laparoscopic techniques for hysterectomy (type not specified) died, but 14 treated with non-laparoscopic techniques died within 6 weeks of the surgery (0.04%, 95% CI 0.025 to 0.064). A non-randomised controlled study of 10,110 women reported that 0.04% (1 out of 2,434) of those who underwent laparoscopic procedures (type not specified) died during the convalescence period (not otherwise defined), compared with 0.06% (1 out of 1,801) of women who had VH and 0.02% (1 out of 5,875) of women who had AH (significance level not stated). The authors stated that the causes of death were alcoholic cirrhosis, cardiac infarct and pulmonary embolism, and were not directly related to the operation.