Westoff C F, McCarthy J
Fam Plann Perspect. 1979 May-Jun;11(3):147-52.
Had no U.S. married couples obtained contraceptive sterilizations, there would have been about 800,000 unwanted births during 1971-1973 in addition to the 8.7 million births that actually occurred. More than half of U.S. couples elect sterilization within 10 years after their last wanted birth, and more than six in 10 are sterilized within 15 years.
如果没有美国已婚夫妇进行避孕绝育手术，那么在1971年至1973年期间，除了实际发生的870万例生育之外，还会有大约80万例意外生育。超过一半的美国夫妇在最后一次期望生育后的10年内选择绝育，超过十分之六的夫妇在15年内进行了绝育。
