Ectopic pregnancy is a complication of pregnancy where a newly formed baby called embryo implants outside the uterus. About 1 to 3% of all pregnancies are ectopic in location and of these 98% occur in the fallopian tubes. Apart from the fallopian tube, ectopic pregnancy can also occur in the cervix, ovaries and abdomen. An embryo implanted in places other than the uterus can cause great tissue damage in its effort to reach a sufficient supply of blood for its growth and needs to be terminated immediately to prevent catastrophic hemorrhage in the woman. Hair-like cilia located on the internal surface of the fallopian tubes are responsible for carrying the fertilized egg to the uterus which in normal circumstances takes 4 to 5 days after ovulation (release of the egg).
Any factor which stops this transport results in the live embryo being retained in the tube where it may start growing to form an ectopic pregnancy. The risk factors predisposing to ectopic pregnancy are fallopian tubal damage caused by pelvic inflammatory disease, chronic pelvic infections and following tubal reconstructive surgeries. In certain women fallopian tube cilia are genetically less in number, predisposing them to recurrent ectopic pregnancies. However, in as many as one third to one half, no risk factor can be identified. Previous history of ectopic pregnancy increases the risk of future ectopic pregnancy to about 10% due to damage to the inner lining of the tube.
To ensure a safer pregnancy following an ectopic where the tube has been retained, it is better to conceive in the menstrual cycle where a woman ovulates from the ovary situated on the side of the non affected tube. For this sometimes ultrasound can be used to detect the side of ovulation. One can try for the next pregnancy soon after resumption of normal menstrual cycle. Once pregnant it is wise to confirm the site of the pregnancy within a week or 10 days of missed periods to ensure that the baby has implanted in the uterus. If both the tubes are unhealthy it may be wiser to resort to IVF where the chances of ectopic pregnancy are lowest.