Infertility is the failure to conceive after 12 months of regular intercourse without the use of a contraceptive method. A couple with a known cause of infertility, such as irregular or infrequent or painful menstruation or a known hormonal disorder or older female age >35 years, should not wait for more than 6 months before seeking help.
There are many lifestyle choices that may reduce the chances of conceiving. Some of these reduce the frequency of intercourse hence the chance for egg and sperm to meet. Some reduce the quality of eggs or sperm; or affect the ability of the uterus to receive an embryo.