How the gestational sac goes up in the uterine cavity can only depend on the development of the embryo itself. The endometrium in the middle and upper part of the uterine cavity is relatively hypertrophic and rich in nutrients. Under normal circumstances, most embryos are planted in the middle and upper part of the uterine cavity, and the trophoblast cells of the embryo can draw enough nutrients from the mother to promote growth. Pregnancy sacs planted in the lower part of the uterine cavity, mostly seen in the uterus with a history of multiple surgeries pregnant women, the normal position of the uterine lining is traumatized, the embryo in order to obtain sufficient nutrition and moved down to the lower part of the middle, compared to the upper part of the uterine cavity, planted in the middle and lower part of the uterine cavity of the embryo is prone to vaginal bleeding, abdominal pain, and other symptoms of miscarriage or even miscarriage. Clinically, for those embryos implanted in the middle and lower uterine cavity, close ultrasound follow-up observation is needed. Whether the embryo can grow upward depends on itself, and human intervention is impossible, so consult the doctor promptly if there is any abnormality.