Ectopic pregnancy may be caused by a number of factors but the most common of them are;
1.Previous tubal inflammation
Diseases like std which lead to pelvic inflammatory disease-causing healing by fibrous tissue & scarring thereby narrowing the tube. There is also the destruction of the cilia & formation of adhesion. This is the most common cause of ectopic pregnancy.
However, it also occurs due to tuberculosis of the pelvis, salpingitis as a result of the heterogeneous spread
2.Previous tubal surgery
Include tuboligation, tuboplasty ( surgery done in case of infertility to correct the tubal blockage or to undo tubal ligation.
3.Developmental abnormalities of the tube
Include diverticula, congenital atresia, excessively large tubes hence fertilized ovum can easily lodge in the tube ( normal is 10 cm long). Very long tube affect the motility of fertilized ovum hence implants in the fallopian tube.
Ciliary dyskinesia- cilia movement in the opposite direction.
4.Peritubal adhesion from the neighbouring structure
Maybe a due post-abortive complication due to septic abortion
Puerperal sepsis, appendicitis may heal with adhesion.
These may occur causing kinking of the tubes & subsequent narrowing.
5.Previous ectopic pregnancy
May be due to the previous salpingitis as with previous intraperitoneal bleeding which distorts the tubes.
Therefore, a woman who had an ectopic pregnancy stands a chance of getting another ectopic pregnancy than a woman who had no ectopia
6.Tumours affecting fallopian tube
Tumours arising from the wall of the fallopian tube or other like myomas (fibroids)
They cause pressure to the tube narrowing it or distorting it from the previous position
Tumours arising from fallopian tube wall are rare but can cause blockage to the tube or narrowing of the same.
7.Multiple previous induced abortions
They increase the risk of salpingitis hence high chances of ectopia
8.Progesterone only contraceptive especially minipills
They relax the wall of the tube & reduce peristaltic movement of the ovum hence interfere with implantation of the fertilized egg in the uterus & favours implantation in the fallopian tube.
9.The late release of the ovum
Is due to a pathological condition associated with the ovary.
10.Use of IUD
Cause altered tubal motility & interferes with implantation of the fertilized egg in the uterus.
Surgeries like laparotomy for any reason will result in healing by fibrosis & formation of adhesion which can distort or narrow the tube.
Ectopic pregnancy can be classified into two types:
- Acute ectopic pregnancy and
- Chronic (slow leak) ectopic pregnancy.