If there is bleeding during intercourse in the first month of pregnancy, it is mainly because the stimulation during intercourse will cause uterine contractions. The main reason why you should not have intercourse in the first trimester is that the embryo is not stable at this time, so once you have intercourse, you will also reach orgasm during intercourse, which will cause sexual excitement and will lead to contraction of the uterus and symptoms of preterm abortion. Once the bleeding occurs during intercourse, it is recommended to go to the hospital for a timely examination to find out if the embryo is still developing normally at this time. If it is still normal, it is recommended to take blood test for HCG and progesterone, and according to the result, treatment should be given to calm the fetus and rest in bed.