Vasectomy Failure Rate: Higher Than We Thought?

Pregnancies have been reported even after vasectomy. To assess the failure rate of vasectomy, investigators examined data from the U.S. Collaborative Review of Sterilization, a prospective cohort study of male and female sterilization that involved 544 women (age range, 18-44) whose husbands underwent vasectomy in one of five U.S. cities between 1985 and 1987. The study excluded women who had undergone tubal ligation or hysterectomy or were no longer married to the partner who had undergone vasectomy.

During telephone calls at 1, 2, 3, and 5 years after vasectomy, the women were asked whether they had been pregnant since the surgery. Ten pregnancies were reported: three determined to have begun before the vasectomy, one about which no additi…