Fetal small three weeks may be the result of wrong accounting of gestational weeks, malnutrition, abnormal fetal development, high blood pressure in pregnancy, etc., through the re-accounting of gestational weeks, nutritional supplements, termination of pregnancy, control of blood pressure to deal with. 1. Incorrect accounting of gestational weeks: the fetus may be small three weeks may be the result of the wrong accounting of gestational weeks, to further verify the early pregnancy ultrasound and gestational weeks are consistent with the early pregnancy ultrasound and gestational weeks do not match the fetus is small three weeks may be normal, temporary observation, usually do a good job of pregnancy and obstetric examination. 2. Malnutrition: Fetal small three weeks may be caused by malnutrition during pregnancy, pregnant women usually need to regulate the dietary habits, eat three meals regularly, eat food rich in protein, vitamins, trace elements, such as chicken, fish, milk, eggs and so on. 3. Fetal development abnormalities: the fetus is small three weeks is caused by fetal development abnormalities, such as serious digestive malformations, fetal chromosomal abnormalities, to do amniocentesis to determine the more serious anomalies in time to terminate the pregnancy. 4. Hypertension in pregnancy: Hypertension in pregnancy will affect the nutrition of the fetus in the uterus and hypoxia, resulting in the fetus small three weeks, to go to the hospital to measure blood pressure, high blood pressure in the doctor’s guidance to lower the pressure, such as nifedipine, nimodipine and other drugs. In the clinic, the fetus is small three weeks to find the cause, and then go to the targeted treatment.