Final answer:
Contraceptive methods like IUDs and hormonal contraceptives can increase the risk of ectopic pregnancy by altering the environment of the reproductive system and affecting tubal motility. Tubal ligation can also increase the risk due to the formation of scar tissue which may impede the proper implantation of a fertilized egg in the uterus.
Step-by-step explanation:
Contraceptive methods such as IUDs (intrauterine devices) and hormonal contraceptives that contain synthetic progesterone can increase the risk of ectopic pregnancy. These methods alter the usual environment of the reproductive system. An IUD works by creating an inflammatory condition in the uterus that prevents a fertilized egg from implanting in the uterine wall. This condition can also alter the motility within the fallopian tubes, which might result in an embryo becoming implanted there, leading to an ectopic pregnancy. Similarly, hormonal contraceptives that prevent the release of FSH or LH might decrease tubal motility, creating potential for a fertilized egg to implant outside the uterus.
Tubal ligation, a form of sterilization for women, can lead to ectopic pregnancy if a pregnancy occurs after the procedure. After a tubal ligation, the remaining segments of the fallopian tubes may develop scar tissue which increases the chance of the embryo implanting in the tube rather than in the uterus.
As contraceptive failure rates vary, it's important to note that even with methods that have low failure rates, such as the implantation of hormones under the skin (<1%), there is still a small chance of conception, which could lead to an ectopic pregnancy if conditions are altered within the fallopian tubes.