Fallopian tube dysfunction in unexplained infertility

Abstract

Unexplained infertility is a "waste basket" diagnosis, encompassing about half of couples experiencing infertility. That infertility is unexplained in at least 50 % of our patients should serve as evidence that we have failed to dissect out the different etiologies comprising this heterogeneous group, while at the same time advancing assisted reproductive technologies. So, while 50 % or more of infertile couples remain undiagnosed, the great majority of them will conceive. And the question, given this reality, is: how much does an accurate diagnosis matter if we can help such couples achieve a successful pregnancy? Does the fallopian tube matter anymore? Frank tubal obstruction, either proximal or distal, has great relevance to the treatment of the infertile patient. Tubal obstruction is still centrally placed in practically every diagnostic algorithm, directing treatment to surgical correction of the abnormality or nonsurgical approaches bypassing the obstruction like in vitro fertilization (IVF). As IVF has become the mainstay of fertility treatment, that paradigm has shifted to performing IVF-first versus IVF as pathway last resort. Can a tube be patent yet nonfunctional? Clearly, in the presence of normal sperm and ovulatory cycles, this tiny, 12-cm-long structure, with its elaborate ciliary lining and sophisticated propulsive mechanism allowing bidirectional traffic of sperm, eggs, and embryos, has the potential for a myriad of aberrations. Hence, tubal dysfunction without mechanical obstruction may be responsible for a significant proportion of unexplained infertility. Currently, we use hysterosalpingography or laparoscopic tubal lavage to diagnose tubal patency. However, the presence of a diseased tube is frequently diagnosed only in retrospect with an ectopic pregnancy. Since nonsurgical treatment is now quite common, most cases of ectopic pregnancy will have a presumed diagnosis of chronic salpingitis without histologic evidence. The exponential rise of IVF as the most successful fertility treatment has markedly diminished the interest in the study of tubal physiology. In this chapter, we would like to revisit the subject. In reexamining tubal pathologies other than mechanical obstruction, we will attempt to outline the various causes of endotubal disease in patients with unexplained infertility and patent tubes.