If the gestational sac is 31×9, it is normal if there is a yolk sac, embryo buds or heart tube pulsation during development, and there is no bleeding or abdominal pain. A gestational sac of 31×9 is consistent with a 7-week intrauterine pregnancy, and there are yolk sacs and embryonic buds or heart tube pulsations in the gestational sac through ultrasound, and as the gestational sac gradually develops, it takes on a human shape in the 8th week of pregnancy. The gestational sac of 31 × 9 is belonging to the early stage of pregnancy, in the unstable period of pregnancy, due to the role of chorionic gonadotropin, most women will occur to varying degrees of dizziness, vomiting, fatigue, loss of appetite, and other early pregnancy reaction, in the pregnancy of 12 weeks or so, the early pregnancy reaction gradually weakened or even completely disappeared. During this period, pregnant women must pay attention to rest, prohibit sexual intercourse, and take oral folic acid until the 12th week of pregnancy. If there is any discomfort during early pregnancy, you need to go to the hospital in time.