What causes the fetus to stop developing during pregnancy? Pregnancy is something that every woman looks forward to, but the fetus stops developing is a very worrying thing. Fetal arrest refers to the natural cessation of growth of the embryo or fetus, which causes great distress to pregnant women and their families. So, what is the cause of fetal arrest? How should we prevent it? Reason 1: Chromosomal Abnormalities The most common cause of fetal arrest is chromosomal abnormalities, which is due to certain errors occurring during the development of the embryo.