The slow growth of fetal buds may be caused by maternal factors or the embryo itself. It is recommended that pregnant women should eat on time, eat more fresh vegetables and fruits, take folic acid supplements in time, observe the growth and development of the embryo, and consult a doctor promptly if there are abnormalities such as bleeding and abdominal pain. Maternal factors: 1. irregular menstruation: some women have irregular menstruation, delayed ovulation, late fertilization of the egg, and the fetal buds may not match the gestational week; however, the growth rate of the fetal buds should be normal; 2. insufficient maternal hormone secretion: human chorionic gonadotropin and progesterone can help embryo growth and development in early pregnancy, if the ovarian corpus luteum secretion of these two hormones decreases, the fetal buds will grow. If the female ovarian corpus luteum secretes these two hormones, the growth of the fetal bud will slow down; 3, the mother suffers from diseases that affect the development of the embryo: such as autoimmune diseases, antiphospholipid syndrome, abnormal thyroid function, etc., which may cause miscarriage, embryonic abortion, and the fetal bud may grow slowly; 4, other: such as pregnant women have smoking, alcohol, drug abuse, etc., these unfavorable factors will directly affect the growth and development of the embryo, resulting in the slow growth of the fetal bud. Second, embryonic factors: after the sperm and egg meet, during the process of gradual development, if they encounter the stimulation of certain physical and chemical factors, it may cause chromosomal abnormalities, thus causing embryonic abortion.