Factors affecting pregnancy come from both the woman and the man, leading to a long time should not be pregnant may be: 1, the woman’s ovaries can not normally ovulate, or ovulation is not regular, can not grasp the ovulation in the period of coitus. 2, although ovulation function is normal, but the fallopian tube is not passable or completely blocked, or suffering from uterine fibroids, uterine adhesions, endometrial tuberculosis and other uterine pathologies, will affect the coitus The chances of conception after intercourse are affected.3. Decrease in the number of sperm in the male semen, lack of vitality, and decrease in the viability rate will also significantly reduce the ability to conceive.4. Although the man and the woman, both of whom do not have any obvious organic diseases, there are anti-sperm antibodies, which lead to immune infertility.