The purpose of an ultrasound in pregnancy is to observe the location of the gestational sac in the bed and the development of the fetal bud. An ultrasound can be done in early pregnancy, around 40 days, when the echogenicity of the gestational sac can be seen in the uterine cavity, and the size of the sac is measured to see if it matches the number of days of pregnancy. If the gestational sac is in the uterine cavity, it is also important to observe whether it is located in the middle of the uterine cavity or near the horn of the uterus. If it is at the horn of the uterus it is a horn pregnancy and very dangerous. If the gestational sac is not visible in the uterine cavity, it is important to focus on exploring the adnexal areas bilaterally to see if there is an echo of the gestational sac and to rule out ectopic pregnancy so as not to delay treatment. During the ultrasound after 45 days of pregnancy, it is important to observe the development of the fetal buds, measure the size of the buds, observe the regularity of the fetal cardiovascular pulsations, and also observe whether there are any masses in the bilateral adnexal areas. In the second trimester, the main purpose of the ultrasound is to observe the position of the placenta and to exclude placenta praevia.