Definitions and epidemiology of unexplained female infertility

Abstract

There are inherent difficulties in defining infertility and unexplained infertility (UI), and the scientific community is yet to reach a consensus opinion. These difficulties stem from the differences in the clinical, epidemiological and demographic approach in defining infertility. Various definitions for infertility have been proposed. The most up-to-date definition states that infertility is a disease, defined by the failure to achieve a successful pregnancy after 12 months or more of appropriate, timed unprotected intercourse or therapeutic donor insemination. UI itself is a diagnosis of exclusion made in the presence of a normal semen analysis when tubal patency and normal ovulatory function are established. It can be further classified into male and female UI, a concept that has only recently emerged. Unexplained female infertility could potentially be attributed to several causes and this association is directly related to the extent that the female is investigated. Studying the epidemiology of infertility and UI is complicated by the disparity in defining the disease as well as the heterogeneity of the studies. It is estimated that in about 30 % of infertile couples seeking help of a reproductive specialists, the cause is unexplained. The prevalence of UI around the world does not vary significantly but the aetiologies do. Investigating and treating women who suffer from UI is constantly evolving in light of new evidence and technologic advances that allow us to identify potential causes that were previously elusive. Therefore, the definition of the disease and its epidemiology are dynamic and may change in the future.