Any married couple who have cohabited without contraception for ≥2 years without pregnancy is referred to as infertility. According to whether or not they have been pregnant after marriage, they can be categorized into primary infertility and secondary infertility. Primary infertility means that there has never been a pregnancy; secondary infertility means that there has been a pregnancy, and there has been no contraception for ≥2 years without another pregnancy. According to the cause of infertility can be divided into: ① relative infertility, refers to one of the couple due to some factors to prevent conception or make fertility decline, after treatment can be conceived; ② absolute infertility, refers to one of the couple has a congenital or acquired anatomical and physiological defects, can not be corrected and can not be conceived. Infertility or infertility refers to a woman’s inability to bear children, infertility is a woman’s inability to conceive, which is the process of fertilization obstacles or early embryo failed to bed in the uterine lining has been lost caused by infertility is a woman can be pregnant, but due to a variety of reasons occurring in the miscarriage, preterm labor or stillbirth, the pregnancy can not be maintained until the live birth. Infertility occurs in the male side is called male infertility, male infertility refers to the sperm production, maturation, transportation or ejaculation ability defects caused by the general term can not bear children. Studies at home and abroad have shown that the chance of conception for each ovulatory menstrual cycle is only 20-25%, and the chance of conception for couples with normal fertility and normal sexual life without contraception for 1 year is 85%, and for 2 years is 93%, (see the table below). However, this decreases with age, and the natural pregnancy rate is significantly lower in women over 35 years of age. Time to conception for normal couples: Time of exposure Chance of conception January 20-25% March 57% June 72% December 85% 24 months 93%