One month pregnant physiological reasons caused by the gestational sac is too small, can be dynamic observation review, due to the embryonic development caused by poor, to follow the doctor’s instructions medication to preserve the fetus treatment. 1. Physiological reasons: when a woman’s menstrual cycle is long, it will lead to late ovulation, which makes the fertilized egg late. Due to the short duration of pregnancy and the first ultrasound in early pregnancy suggests that the gestational sac is too small, this is a normal physiological phenomenon, according to the size of the gestational sac to re-check the gestational week, and comply with the doctor’s instructions for dynamic observation, 7-10 days to re-examination. 2. Embryonic dysplasia: early pregnancy ultrasound suggests that the gestational sac or buds are too small, check the gestational week in line with the possibility of embryonic dysplasia, can also be combined with progesterone, estradiol and blood HCG (human chorionic gonadotropin) levels to assist in the diagnosis of the need to comply with the doctor’s advice to give dextroprogesterone, low molecular heparin and other drugs to protect the fetus treatment, and in about 7 days to review. When the first month of pregnancy is too small, it is necessary to find out the cause under the guidance of the doctor and actively manage it. In addition, the use of specific drugs need to be under the guidance of the doctor, do not take on their own.