Doing vaginal ultrasound after intercourse will not affect the fertilization of the egg, because after intercourse the sperm and the egg are fertilized inside the fallopian tube, and then return to the uterine cavity for fertilization. Generally regular hospitals do vaginal ultrasound is the vaginal probe into the vagina, the top will be on top of the cervix will not be put into the uterine cavity, and vaginal ultrasound belongs to the ultrasound is not radiation, also does not affect the fertilization of eggs. Ultrasound examination time is usually about 15 minutes, so ultrasound is almost no harm to the fertilized egg or fetus, will not affect the formation of fertilized eggs and implantation. It is possible to do vaginal ultrasound during the preparation for pregnancy to understand the ovulation situation or early pregnancy to rule out ectopic pregnancy, timely ultrasound is meaningful for determining the normal development of the fetus or whether there is advantageous ovulation, so women or pregnant women should not be afraid of vaginal ultrasound.