Infertility — Causes and an Overview

Infertility is generally understood as the inability of a couple to achieve a pregnancy despite regular, unprotected sexual intercourse continued over a reasonably extended period, commonly taken as roughly a year or more. It is important to be clear that infertility is not, in itself, a single disease with one cause; it is better thought of as an outcome that can result from a wide and varied range of underlying conditions, which may originate in the male partner, the female partner, both partners together, or, in a proportion of couples even after careful investigation, remain without an identifiable cause.

Broadly, the possible causes taught at this level can be grouped as follows. PHYSICAL or STRUCTURAL causes include a blockage somewhere along the reproductive tract — for instance, in the fallopian tubes in a woman, preventing the egg and sperm from meeting, or in the sperm-carrying ducts in a man — or structural abnormalities of the uterus or other reproductive organs. HORMONAL causes include irregular or absent ovulation in the woman, or inadequate production of sperm in the man, both ultimately traceable to disturbances in the hormonal signals that normally regulate reproduction. CONGENITAL causes are abnormalities present from birth affecting the structure or function of the reproductive organs. DISEASE-RELATED causes include the after-effects of certain infections — untreated sexually transmitted diseases (Section 3.3) being a notable example, since conditions such as untreated gonorrhoea or chlamydial infection can scar and block the fallopian tubes — as well as certain other chronic illnesses. Some cases arise as a side effect of particular DRUGS or medical treatments, or from IMMUNOLOGICAL factors in which the body's own immune response interferes with fertilisation. In a smaller proportion of couples, PSYCHOLOGICAL factors such as chronic stress are considered a contributing influence, though this is only one factor among the many listed here, and rarely the sole or primary explanation. …