40 days after the birth of coitus will not lead to pregnancy, but 40 days after the birth of coitus is not allowed, in the 42 days after the birth of coitus are still in the puerperium, in this period of time is the mother’s uterus, vagina, the whole body recovery stage, in the body is not fully recovered in the case of coitus too early will increase the risk of infection, hemorrhage. On the uterus, body recovery, as well as the cervix and vagina will have an impact on the recovery, but also increase the probability of inflammation in the future, so for the sake of maternal health, as well as future gynecological health is recommended in the postpartum within 2 months can not have intercourse. Only after 2 months can gradually resume married life, and to do a good job of contraception can not get pregnant too early, if it is a cesarean section to 1 ½ years before being able to get pregnant again.