At 18 weeks the fetus is usually in the lower part of the navel about 2 fingers, but every pregnant woman and fetus in the uterus are not quite the same, so you can’t generalize. Generally after 12 weeks of pregnancy, the fetus can almost enter the abdominal cavity, because in the middle of pregnancy, the fetus will further increase in size, at the same time the amniotic fluid will gradually increase, the fetus in the uterine cavity will gradually become active, so the general position is also floating. At 18 weeks of pregnancy, midterm Down’s syndrome screening is needed to rule out the possibility of Down’s syndrome, and to observe the fetus in the uterus through ultrasound, etc. If there is any abnormality in the 18th week of pregnancy, then it is recommended to consult a doctor in time and choose the appropriate way of treatment.