It is normal for a woman to have a gynecologic ultrasound that shows an oval-shaped gestational sac. Although there is tension inside the gestational sac and theoretically it should be a round shape, the gestational sac is inside the woman’s uterine cavity, which is normally closed, mainly because there is pressure on the myometrium and the anterior and posterior walls of the uterus are closed in the absence of pregnancy. After pregnancy the gestational sac is squeezed by the myometrium within a narrow space, so it does not become round, but oval. If the gestational sac is not well developed and has bad tension, it will be irregularly shaped under the compression of the myometrium and will not be oval. Therefore, if the ultrasound indicates that the gestational sac is oval, it means that the embryo is still developing OK, however, the blood progesterone and HCG need to be checked to observe the activity of the gestational sac.