Ectopic pregnancy means implantation of the zygote anywhere in the body outside of the uterus. The most common locations are the fallopian tubes, ovaries, cervix or even abdomen.
The pregnancy poses a threat to both the viability of the fetus as its chances of making to full-term are negligible and it can rupture and cause serious morbidity to the mother!
The contributing causes toward ectopic pregnancy include the scarring of the fallopian tubes because of pelvic inflammatory disease or previous surgery or sterlization procedures.
Also IUCD as it suppresses the chances of normal pregnancy, it is likely the pregnancy that eventually does occur with IUCD is ectopic. Hope my response helped you.