A mere bumpy ride in a car in the early stages of pregnancy does not cause significant adverse effects on the development of the fetus. However, the sensitivity to stimulation by various harmful factors and the stability of the gestational sac in the early stages of pregnancy differ from one pregnant woman to another, and the resulting reactions are not exactly the same. In pregnant women who have never experienced abdominal pain or abnormal bleeding in the vagina during pregnancy, a slight bump in the car will not cause abnormalities in pregnant women. However, in the early stage of pregnancy, frequent abnormal vaginal bleeding or repeated lower abdominal pain indicates that the baby is not very stable in the uterine cavity and the bumpy car ride may induce uterine contractions and cause miscarriage, which should be avoided.