Infertility primarily refers to the biological inability of a person to contribute to conception . Infertility may also refer to the state of a woman who is unable to carry a pregnancy to full term . There are many biological causes of infertility, some which may be bypassed with medical intervention. Women who are fertile experience a natural period of fertility before and during ovulation , and they are naturally infertile during the rest of the menstrual cycle . Fertility awareness methods are used to discern when these changes occur by tracking changes in cervical mucus or basal body temperature .