Background –Pregnancy loss in first trimester is due to multiple known and some unknown factors. Yolk sac also plays a major role in early pregnancy by providing nutrition to the early pregnancy developing embryo. Sometimes abnormal yolk sac morphology leads to poor pregnancy outcome. So in this study we tried to find out the correlation of yolk sac morphology as the size ,shape, ecogenesity with respect to pregnancy outcome uptill 20 week pregnancy.