A state of being less than normally fertile, but not infertile.

Infertility that is not 'absolute', or 'complete infertility' -- that is, there is a chance of pregnancy: it is not sterility (these last 3 terms are synonyms) -- but the chance of getting pregnant each month (fecundability or monthly fertility) is reduced. More or less definite causes can include oligospermia, polycystic ovary syndrome and other causes of oligomenorrhea, endometriosis, peritubal adhesions, fibroids (especially submucous fibroids) and increased age, especially of the woman. Synonymous with relative infertility. See also: cumulative chance of pregnancy See also: K-selection

A state of reduced fertility.

Inability of a couple to conceive after a year of regular sexual intercourse, without using any form of contraception.

When a couple's chances of conceiving are lower than is usual.