Ectopic pregnancy (EP) is an enigmatic reproductive disorder. Although tubal EP is difficult to predict, several hypotheses about its etiology have been proposed. In retrospective case-control studies, smoking is associated with an increased rate of EPs in the fallopian tube. Studies of experimental animals in vivo and human fallopian tubal tissues in vitro have suggested mechanisms of fallopian tubal damage and dysfunction induced by nicotine and other smoking-related chemicals that may explain this association. However, the pathogenesis of smoking-induced modulation of implantation leading to tubal EP is largely unknown. Because cigarette/tobacco smoke adversely affects the success of intrauterine implantation, there is a great need to determine how embryo implantation occurs in the fallopian tube in female smokers of reproductive age.