Ectopic pregnancy is a pregnancy which occurs outside the uterus. Fertilisation usually takes place in the fallopian tube, and the fertilised egg is swept along by the action of tiny hairs called cilia to implant in the wall of the uterus. In an ectopic pregnancy the implantation occurs elsewhere - usually in the fallopian tube itself. It is a condition which is much more likely to occur if there is a problem with the transport of the egg down the fallopian tube. This is more likely if there has been damage to the tube by infection or inflammation, if there has been a previous ectopic pregnancy, if there is an intra-uterine contraceptive device or if the progesterone only contraceptive pill is being used. Ectopic pregnancy is a dangerous condition: those with a missed period and abdominal pain should seek medical attention.