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, including some that medical intervention can treat. Infertility has increased by 4 percent since the 1980s, mostly from problems with fecundity due to an increase in age.

About 40 percent of the issues involved with infertility are due to the man, another 40 percent due to the woman, and 20 percent result from complications with both partners. 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.

Primary sterility, either asthenia or sthneia, should be differentiated according to the age of menarche, menstruation, the secondary sex characteristic and constitution. Primary sterility of asthenia nature is marked by late occurrence of menarche, delayed menstruation, scanty menorrhea with light or grayish color and thin texture and scanty leukorrhea. Primary sterility of asthenia nature is marked by scanty menorrhea with grayish color and multiple blood clots, unpressable distending pain in lower abdomen. The root cause lies in the kidney, but the liver, spleen and qi and blood must be taken into consideration.