animation, ectopic pregnancy, diagram picture ECTOPIC.gif Ectopic pregnancies occur when the fertilized ovum implants outside of the uterine fundus. About 1 in 150 pregnancies results in ectopic implantation. Most cannot be sustained at extrauterine sites. However, a tubal ectopic pregnancy, as diagrammed here, may proceed for several weeks, but the enlargement can rupture the tube and lead to acute, life-threatening bleeding, often about 6 weeks after a previous menstrual period.